Bike fit analysis methodology

Evidence and limits behind an OpenBikeFit analysis

The analysis keeps three layers separate: measurements from the bike, published reference ranges and repeated 2D camera estimates.

Use the registry below to inspect every active claim, its evidence strength, where it changes the product and where the evidence stops. Population research never becomes a promise about one rider.

See a fictional analysis Start measuring Camera method

Evidence becomes useful only when the physical reference, measurement method and uncertainty stay visible together.

Mapped claims: 11
Referenced sources: 20
Evidence topics: 6

What the calculator assumes — and does not measure

Saddle height is an app-specific anthropometric estimate. The calculator has no measured knee-angle, femur or shank input. A research paper about a measured angle does not validate this numeric conversion.

Historical ratio: 0.883 × inseam in mm; This gives the raw LeMond reference. It does not measure knee motion, segment lengths or an installed bicycle.
App corrections: (175 − crank mm) − 4 mm; The 175 mm baseline and fixed −4 mm term are app conventions, not a measurement of your pedal/shoe assembly. The full tool may estimate the crank term when no current length was entered.
App angle-band approximation: (30 − band angle) × 0.0022 × inseam mm; The angle is a selected reference-band argument, not your measured knee angle. No cited paper was established as validating the app-specific coefficient or its inseam-to-height conversion.

The terms are added before the existing profile modifiers and display rounding. The main calculator assumes the fixed −4 mm term; the separate quick tool adds 4 mm back when its flat-pedal choice is selected. These are transparent software assumptions, not independently verified physical corrections.

Fictional arithmetic, not a rider measurement

For inseam 82 cm and a declared 172.5 mm crank: raw LeMond 724.06 mm; Hamley conversion 721.30 mm; app base at its nominal 30° argument 722.56 mm. Its 25° and 35° arguments give 731.58 and 713.54 mm before profile modifiers. They do not show that a person actually has any of those knee angles.

The dynamic band adds 5° to the selected static band as an app convention. It is not a universal conversion between instruments. A study-specific 2D/3D correction, a projected phone angle and a static goniometer result cannot be silently substituted for each other. Tracking confidence and repeated agreement do not certify absolute accuracy.

A calculated reference is not an installed coordinate. An optional current setting is your declaration, not something the app inspected. Read the physical endpoint and repeatable-measurement guides separately. No number here approves compatibility, installation, health, comfort, performance or readiness to ride.

Source identity is a check, not product validation

This dated ledger covers all 22 central references. A source-type label describes the publication, not the certainty of an app result. Matching authors, title and identifier does not prove a claim or validate our formulas. Public abstracts were read where available; complete papers and book pages were not reviewed in this audit.

Eight previously mismatched PubMed links were corrected on 14 October 2026. The record below names exactly what was checked and leaves missing source access visible. It is not a clinical, legal or installation certificate, nor continuous monitoring of publisher updates.

Hamley E.J., Thomas V. (1967) · Physiological and postural factors in the calibration of the bicycle ergometer
Reported source type: peer-reviewed · Journal of Physiology, 191:55–56P
Bibliographic identity only · 14 October 2026
NLM bibliographic identity checked; no public abstract or original text inspected.
PMID 6050117
Historical bibliographic reference for the 109%-of-inseam convention. The indexed record has no abstract; the original communication was not inspected in this audit. The app's endpoint conversion is a separate model assumption.
Open this named source — new tab
LeMond G., Gordis K. (method: C. Guimard) (1987) · Greg LeMond's Complete Book of Bicycling
Reported source type: convention · Putnam, 1987 edition (ISBN 0399132295)
Catalog identity only · 14 October 2026
The 1987 Putnam edition is confirmed by a library catalog. Calculation pages, 175 mm assumptions and shoe corrections were not inspected.
Historical book reference associated with the 88.3%-of-inseam convention. A catalog confirms the 1987 Putnam edition, not the calculation pages. The app's 175 mm crank baseline and fixed -4 mm term are not verified findings from this book.
Holmes J.C., Pruitt A.L., Whalen N.J. (1994) · Lower extremity overuse in bicycling
Reported source type: peer-reviewed · Clinics in Sports Medicine, 13(1):187–205
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 8111852
Clinical review of overuse in cycling. Its public abstract discusses repetition and cyclist/bicycle factors; it does not expose a validated inseam-to-angle conversion or the app's coefficient. No clinical instruction is inferred here.
Open this named source — new tab
Peveler W.W. (2008) · Effects of saddle height on economy in cycling
Reported source type: peer-reviewed · Journal of Strength and Conditioning Research, 22(4):1355–1359
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 18545167 · DOI 10.1519/JSC.0b013e318173dac6
In 15 participants (5 cyclists and 10 noncyclists), oxygen uptake differed between the tested measured-angle and inseam-based conditions. This protocol does not validate an app-specific formula or an individual outcome.
Open this named source — new tab
Peveler W.W., Green J.M. (2011) · Effects of saddle height on economy and anaerobic power in well-trained cyclists
Reported source type: peer-reviewed · Journal of Strength and Conditioning Research, 25(3):629–633
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 20581695 · DOI 10.1519/JSC.0b013e3181d09e60
In 11 trained male cyclists, measured-angle conditions and 109%-of-inseam conditions differed; 73% of the latter were outside the study's 25–35° reference. This is one sample, not an app failure rate or a universal target.
Open this named source — new tab
Bini R., Hume P.A., Croft J.L. (2011) · Effects of bicycle saddle height on knee injury risk and cycling performance
Reported source type: systematic review · Sports Medicine, 41(6):463–476
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 21615188 · DOI 10.2165/11588740-000000000-00000
Review of 62 references with conflicting methods, small samples and limited injury evidence. It discusses a measured knee-angle approach; it does not validate OpenBikeFit's anthropometric conversion, coefficient or an individually safe position.
Open this named source — new tab
Ferrer-Roca V., Roig A., Galilea P., García-López J. (2012) · Influence of saddle height on lower limb kinematics in well-trained cyclists: static vs. dynamic evaluation in bike fitting
Reported source type: peer-reviewed · Journal of Strength and Conditioning Research, 26(11):3025–3029
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 22190163 · DOI 10.1519/JSC.0b013e318245c09d
The study compared anthropometric and 2D dynamic approaches and reported disagreement with its chosen references. Its regression and 30–40° context are protocol-specific, not OpenBikeFit calibration or a universal static-to-dynamic offset.
Open this named source — new tab
Fonda B., Sarabon N., Li F.-X. (2014) · Validity and reliability of different kinematics methods used for bike fitting
Reported source type: peer-reviewed · Journal of Sports Sciences, 32(10):940–946
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 24499342 · DOI 10.1080/02640414.2013.868919
Eleven cyclists were measured with 3D cameras, high-speed 2D video and an electrogoniometer. The reported 2.2° correction belongs to that 2D-versus-3D protocol; it is not a universal +5° rule or calibration of a MediaPipe phone estimate.
Open this named source — new tab
Martin J.C., Spirduso W.W. (2001) · Determinants of maximal cycling power: crank length, pedaling rate and pedal speed
Reported source type: peer-reviewed · European Journal of Applied Physiology, 84(5):413–418
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 11417428 · DOI 10.1007/s004210100400
Sixteen trained cyclists tested 120–220 mm cranks. Maximum power ranged from 1149 to 1194 W, with significant differences between some lengths. Cadence and pedal speed mattered; these results do not establish one length or guarantee equal power for every rider.
Open this named source — new tab
Barratt P.R., Korff T., Elmer S.J., Martin J.C. (2011) · Effect of crank length on joint-specific power during maximal cycling
Reported source type: peer-reviewed · Medicine & Science in Sports & Exercise, 43(9):1689–1697
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 21311357 · DOI 10.1249/MSS.0b013e3182125e96
Fifteen trained cyclists tested 150–190 mm cranks. Relative joint powers did not significantly differ at optimized cadence, but some differences appeared at fixed 120 rpm. The finding is conditional, not a universal no-effect claim.
Open this named source — new tab
Ferrer-Roca V. et al. (2017) · Acute effects of small changes in crank length on gross efficiency and pedalling technique during submaximal cycling
Reported source type: peer-reviewed · Journal of Sports Sciences, 35(14):1328–1335
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 27484153 · DOI 10.1080/02640414.2016.1215490
Twelve amateur road cyclists tested their preferred length and +/-5 mm at fixed cadence and three workloads. Gross efficiency and heart rate did not significantly differ, while some joint-motion measures did. This acute protocol is not a personal crank-length prescription.
Open this named source — new tab
Ménard M., Domalain M., Decatoire A., Lacouture P. (2020) · Influence of saddle setback on knee joint forces in cycling
Reported source type: peer-reviewed · Sports Biomechanics, 19(2):245–257 · PubMed 29920153
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 29920153 · DOI 10.1080/14763141.2018.1466906
In ten cyclists across three large setback conditions, model-estimated tibiofemoral compression differed between forward and backward positions. The study did not establish a pain-specific adjustment direction or universal setback.
Open this named source — new tab
Bontrager K. (1998) · The Myth of K.O.P.S.
Reported source type: convention · Bicycle Guide (reprint: sheldonbrown.com)
Named webpage checked · 14 October 2026
Named practitioner reprint read, including dated author notes; not a controlled study or app calibration.
A practitioner critique of treating a gravity-based knee/pedal alignment as a universal biomechanical law. The reprint is an argument and explanation, not a controlled trial or validation of the app's setback bands.
Open this named source — new tab
UCI (2024) · UCI Technical Regulations, art. 1.3.013
Reported source type: convention · Union Cycliste Internationale
Original rules not reviewed · 14 October 2026
Historical registry entry. Complete currently applicable competition rules were not reviewed; this is not event eligibility or current legal approval.
Historical 2024 regulatory entry, not current event eligibility or fit evidence. This source audit did not inspect the complete currently applicable rulebook; use the exact event, category and date rather than this entry as permission.
Gnehm P., Reichenbach S., Altpeter E., Widmer H., Hoppeler H. (1997) · Influence of different racing positions on metabolic cost in elite cyclists
Reported source type: peer-reviewed · Medicine & Science in Sports & Exercise, 29(6):818–823
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 9219211 · DOI 10.1097/00005768-199706000-00013
Fourteen elite male racers were tested in three positions without outdoor wind resistance. The paper compared an estimated metabolic power cost with expected aerodynamic savings; it did not measure a guaranteed 100 W saving for a rider.
Open this named source — new tab
Fintelman D.M., Sterling M., Hemida H., Li F.-X. (2015) · The effect of time trial cycling position on physiological and aerodynamic variables
Reported source type: peer-reviewed · Journal of Sports Sciences, 33(16):1730–1737
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 25658151 · DOI 10.1080/02640414.2015.1009936
Nineteen trained male cyclists tested five torso-angle conditions; physiological variables and frontal area were measured. Frontal area estimated drag rather than directly measuring every outdoor aerodynamic outcome. No universal handlebar-drop value follows.
Open this named source — new tab
Van Sickle J.R., Hull M.L. (2007) · Is economy of competitive cyclists affected by the anterior-posterior foot position on the pedal?
Reported source type: peer-reviewed · Journal of Biomechanics, 40(6):1262–1267
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 16901493 · DOI 10.1016/j.jbiomech.2006.05.026
Eleven competitive cyclists tested three foot-attachment positions at a fixed cadence and workload near 90% of ventilatory threshold. Oxygen uptake did not significantly differ in that protocol; injury prevention and a universal cleat target were not established.
Open this named source — new tab
Salai M., Brosh T., Blankstein A., Oran A., Chechik A. (1999) · Effect of changing the saddle angle on the incidence of low back pain in recreational bicyclists
Reported source type: peer-reviewed · British Journal of Sports Medicine, 33(6):398–400
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 10597848 · DOI 10.1136/bjsm.33.6.398
The public abstract reports improvement after a saddle-angle intervention in a symptomatic cycling-club group. It does not validate OpenBikeFit or a universal tilt. Specific full-text percentages or angle recipes are not adopted from this abstract.
Open this named source — new tab
Akuthota V., Plastaras C., Lindberg K., Tobey J., Press J., Garvan C. (2005) · The effect of long-distance bicycling on ulnar and median nerves: an electrophysiologic evaluation of cyclist palsy
Reported source type: peer-reviewed · American Journal of Sports Medicine, 33(8):1224–1230
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 16000656 · DOI 10.1177/0363546505275131
Fourteen participants were assessed before and after a six-day tour. Some measured nerve-conduction outcomes changed; this observational protocol does not identify one cause or establish a drop/reach/grip adjustment to treat an individual symptom.
Open this named source — new tab
Silberman M.R., Webner D., Collina S., Shiple B.J. (2005) · Road bicycle fit
Reported source type: peer-reviewed · Clinical Journal of Sport Medicine, 15(4):271–276
Bibliographic identity only · 14 October 2026
NLM bibliographic identity checked; no public abstract or original text inspected.
PMID 16003043 · DOI 10.1097/01.jsm.0000171255.70156.da
Bibliographic identity of this clinical review was checked. PubMed exposes no abstract and the original text was not inspected in this audit; specific fitting landmarks or outcome claims are not asserted from that record alone.
Open this named source — new tab
Husband S.P., Wainwright B., Wilson F. et al. (2024) · Cycling position optimisation - a systematic review of the impact of positional changes on biomechanical and physiological factors in cycling
Reported source type: systematic review · Journal of Sports Sciences, 42(15):1477–1490
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 39285616 · DOI 10.1080/02640414.2024.2394752
The review screened 16,578 records and analysed 47 studies, with substantial quality and representation limits. It found no clear recommendations for crank length, handlebar height, Q factor or cleat position. This does not validate the app's particular formulas or every saddle-width rule.
Open this named source — new tab
Castilla Pikaza A., Iriberri J. (2025) · Injuries caused by poor biomechanical fit in cycling: a narrative review
Reported source type: conference abstract · Journal of Science and Cycling, Science and Cycling Conference 2025 abstract
Named webpage checked · 14 October 2026
Publisher identity and conference abstract read. No complete review text or individual clinical/causal outcome validated.
The publisher presents a conference abstract describing a review of biomechanical injury literature. It is not a full clinical validation report, a causal map for a rider, or evidence that this app should personalize from symptoms.
Open this named source — new tab

Explore by topic

Each link lands on a server-rendered section. Individual claims also have permanent anchors that can be cited or shared directly.

How to read the evidence grades

Source type and claim strength answer different questions. A source badge says what was published: a systematic review, a peer-reviewed paper, or a convention. The claim grade says how confidently that material supports the specific product statement on this page.

A systematic review can conclude that evidence is weak. A conference abstract is not the complete review it describes. Conversely, a repeatable fitter convention can be useful without becoming scientific consensus. OpenBikeFit keeps those categories separate so a prestigious source label cannot silently inflate a modest conclusion.

Supported reference: Relevant research supports the stated literature context. This grade does not validate the app's derived numbers, coefficients or an individual prescription.
Directional evidence: Research supports the direction of an effect, but not one universal target for every rider.
Evidence uncertain: The available evidence is too limited or indirect for a confident product rule, so the product exposes the uncertainty.
Fitter convention: An explicitly labelled app or practitioner convention, not a scientifically established individual target or permission to modify a bicycle.

Repeat the same declared reference before treating a difference as a real setup change.

Source quality and claim strength stay separate: several papers can still support only a cautious conclusion.

Evidence topic

Saddle position

Height, fore-aft position and tilt.

Back to topics

Claim 1 of 4 in this topic

Saddle height is the best-supported fit variable

Supported reference

Measured knee-angle protocols provide literature context for saddle height. A static reference, a dynamic 2D observation and an inseam-based app estimate are different quantities; none automatically validates the others.

Evidence, limits and sources

Why this grade

The 2011 review discusses a measured-angle approach alongside conflicting methods and small samples. The 2024 review reports broad evidence-quality limits. Fonda's instrument-specific experiment does not establish a universal static-to-dynamic offset or validate OpenBikeFit's coefficient.

Grade meaning: Relevant research supports the stated literature context. This grade does not validate the app's derived numbers, coefficients or an individual prescription.

Where OpenBikeFit uses it

Bike fit calculatorComputes an app-specific inseam approximation and exposes its fixed corrections and band argument. It has no measured knee-angle or segment-length input.
Saddle height calculatorExplains the measurement convention and gives a range that can be checked on the bike.
Live camera fitInterprets the knee angle as a dynamic measurement and keeps it separate from static goniometer targets.

Limitations

A population reference range does not determine one perfect angle for an individual rider.
Marker placement, camera perspective, ankle motion and pedalling load can change the measured angle.
This educational product does not assess a health concern or establish installation or riding safety.

Sources mapped to this claim

5 sources

Husband S.P., Wainwright B., Wilson F. et al. (2024). Cycling position optimisation - a systematic review of the impact of positional changes on biomechanical and physiological factors in cycling. Journal of Sports Sciences, 42(15):1477–1490.
systematic review
Registry finding: The review screened 16,578 records and analysed 47 studies, with substantial quality and representation limits. It found no clear recommendations for crank length, handlebar height, Q factor or cleat position. This does not validate the app's particular formulas or every saddle-width rule.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 39285616 · DOI 10.1080/02640414.2024.2394752
Open source
Holmes J.C., Pruitt A.L., Whalen N.J. (1994). Lower extremity overuse in bicycling. Clinics in Sports Medicine, 13(1):187–205.
peer-reviewed
Registry finding: Clinical review of overuse in cycling. Its public abstract discusses repetition and cyclist/bicycle factors; it does not expose a validated inseam-to-angle conversion or the app's coefficient. No clinical instruction is inferred here.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 8111852
Open source
Bini R., Hume P.A., Croft J.L. (2011). Effects of bicycle saddle height on knee injury risk and cycling performance. Sports Medicine, 41(6):463–476.
systematic review
Registry finding: Review of 62 references with conflicting methods, small samples and limited injury evidence. It discusses a measured knee-angle approach; it does not validate OpenBikeFit's anthropometric conversion, coefficient or an individually safe position.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 21615188 · DOI 10.2165/11588740-000000000-00000
Open source
Ferrer-Roca V., Roig A., Galilea P., García-López J. (2012). Influence of saddle height on lower limb kinematics in well-trained cyclists: static vs. dynamic evaluation in bike fitting. Journal of Strength and Conditioning Research, 26(11):3025–3029.
peer-reviewed
Registry finding: The study compared anthropometric and 2D dynamic approaches and reported disagreement with its chosen references. Its regression and 30–40° context are protocol-specific, not OpenBikeFit calibration or a universal static-to-dynamic offset.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 22190163 · DOI 10.1519/JSC.0b013e318245c09d
Open source
Fonda B., Sarabon N., Li F.-X. (2014). Validity and reliability of different kinematics methods used for bike fitting. Journal of Sports Sciences, 32(10):940–946.
peer-reviewed
Registry finding: Eleven cyclists were measured with 3D cameras, high-speed 2D video and an electrogoniometer. The reported 2.2° correction belongs to that 2D-versus-3D protocol; it is not a universal +5° rule or calibration of a MediaPipe phone estimate.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 24499342 · DOI 10.1080/02640414.2013.868919
Open source

Claim 2 of 4 in this topic

Inseam formulas are estimates, not validation

Directional evidence

The 88.3%-of-inseam and 109%-of-inseam methods are fast historical starting points. They should be checked against knee motion because a formula can place a rider outside the studied knee-angle range.

Evidence, limits and sources

Why this grade

The two historical ratios have different endpoints. Peveler and Green studied 11 trained male cyclists and reported the 73% result for their own protocol. Hamley's indexed entry has no abstract and LeMond's book pages were not inspected in this audit; app corrections stay separate from those sources.

Grade meaning: Research supports the direction of an effect, but not one universal target for every rider.

Where OpenBikeFit uses it

Bike fit calculatorShows historical ratio values beside an explicitly app-specific estimate; source identity does not establish individual measurement or validation.
Saddle height calculatorShows why two common formulas can disagree and why the result is a setup range rather than a verdict.

Limitations

The cited 73% result comes from one study population and is not a failure rate for every rider.
Inseam measurements themselves vary with stance, tool placement and the pressure used at the crotch.
Shoes, pedals, crank length and saddle shape affect how a calculated height translates to the bike.

Sources mapped to this claim

3 sources

Hamley E.J., Thomas V. (1967). Physiological and postural factors in the calibration of the bicycle ergometer. Journal of Physiology, 191:55–56P.
peer-reviewed
Registry finding: Historical bibliographic reference for the 109%-of-inseam convention. The indexed record has no abstract; the original communication was not inspected in this audit. The app's endpoint conversion is a separate model assumption.
Bibliographic identity only · 14 October 2026
NLM bibliographic identity checked; no public abstract or original text inspected.
PMID 6050117
Open source
LeMond G., Gordis K. (method: C. Guimard) (1987). Greg LeMond's Complete Book of Bicycling. Putnam, 1987 edition (ISBN 0399132295).
convention
Registry finding: Historical book reference associated with the 88.3%-of-inseam convention. A catalog confirms the 1987 Putnam edition, not the calculation pages. The app's 175 mm crank baseline and fixed -4 mm term are not verified findings from this book.
Catalog identity only · 14 October 2026
The 1987 Putnam edition is confirmed by a library catalog. Calculation pages, 175 mm assumptions and shoe corrections were not inspected.
Peveler W.W., Green J.M. (2011). Effects of saddle height on economy and anaerobic power in well-trained cyclists. Journal of Strength and Conditioning Research, 25(3):629–633.
peer-reviewed
Registry finding: In 11 trained male cyclists, measured-angle conditions and 109%-of-inseam conditions differed; 73% of the latter were outside the study's 25–35° reference. This is one sample, not an app failure rate or a universal target.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 20581695 · DOI 10.1519/JSC.0b013e3181d09e60
Open source

Claim 3 of 4 in this topic

KOPS is a reference line, not a biomechanical law

Fitter convention

Knee-over-pedal-spindle can be a repeatable setup reference, but the plumb line does not identify a universally optimal saddle setback. Fore-aft position still matters because it can change model-estimated knee forces and rider balance.

Evidence, limits and sources

Why this grade

The KOPS critique explains why gravity-based alignment has no special relationship to force around the crank. Separate peer-reviewed modelling work found different knee-joint forces across setback conditions, supporting cautious measurement rather than obedience to one line or a pain-derived direction.

Grade meaning: An explicitly labelled app or practitioner convention, not a scientifically established individual target or permission to modify a bicycle.

Where OpenBikeFit uses it

Bike fit calculatorUses app setback conventions without a universal optimum or a symptom-selected direction; it does not measure knee-joint forces.
Bike fit learning hubSeparates setup conventions from stronger evidence so a familiar rule is not presented as settled science.

Limitations

The KOPS critique is a practitioner argument, not a controlled clinical trial.
The ten-cyclist modelling study shows that setback can matter; it does not provide one correct setback or a pain-specific direction for every body and bicycle.
Racing regulations can impose a legal saddle position that is separate from comfort or biomechanics.

Sources mapped to this claim

3 sources

Bontrager K. (1998). The Myth of K.O.P.S.. Bicycle Guide (reprint: sheldonbrown.com).
convention
Registry finding: A practitioner critique of treating a gravity-based knee/pedal alignment as a universal biomechanical law. The reprint is an argument and explanation, not a controlled trial or validation of the app's setback bands.
Named webpage checked · 14 October 2026
Named practitioner reprint read, including dated author notes; not a controlled study or app calibration.
Open source
Ménard M., Domalain M., Decatoire A., Lacouture P. (2020). Influence of saddle setback on knee joint forces in cycling. Sports Biomechanics, 19(2):245–257 · PubMed 29920153.
peer-reviewed
Registry finding: In ten cyclists across three large setback conditions, model-estimated tibiofemoral compression differed between forward and backward positions. The study did not establish a pain-specific adjustment direction or universal setback.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 29920153 · DOI 10.1080/14763141.2018.1466906
Open source
Silberman M.R., Webner D., Collina S., Shiple B.J. (2005). Road bicycle fit. Clinical Journal of Sport Medicine, 15(4):271–276.
peer-reviewed
Registry finding: Bibliographic identity of this clinical review was checked. PubMed exposes no abstract and the original text was not inspected in this audit; specific fitting landmarks or outcome claims are not asserted from that record alone.
Bibliographic identity only · 14 October 2026
NLM bibliographic identity checked; no public abstract or original text inspected.
PMID 16003043 · DOI 10.1097/01.jsm.0000171255.70156.da
Open source

Claim 4 of 4 in this topic

Saddle tilt should be tested, not prescribed aggressively

Directional evidence

The cited saddle-angle paper concerns a symptomatic cohort, not a universal angle or a validated rule in this application. Its clinical outcome is not a reason to personalize this educational workflow from health information.

Evidence, limits and sources

Why this grade

Salai's public abstract reports an intervention outcome. The complete intervention and population cannot be replaced with a generic tilt recipe. The source ledger states abstract-only access, and no health-directed instruction is adopted.

Grade meaning: Research supports the direction of an effect, but not one universal target for every rider.

Where OpenBikeFit uses it

Evidence and methodologyKeeps this study's context and reading limits visible. The nine-metric body calculator does not output a saddle-tilt recommendation.

Limitations

The study population and intervention do not represent every saddle, riding posture or cause of back pain.
The source does not approve an installation or a tilt for an unmeasured saddle, assembly or rider.
Back pain can have causes that a bicycle-position change cannot identify or treat.

Sources mapped to this claim

2 sources

Salai M., Brosh T., Blankstein A., Oran A., Chechik A. (1999). Effect of changing the saddle angle on the incidence of low back pain in recreational bicyclists. British Journal of Sports Medicine, 33(6):398–400.
peer-reviewed
Registry finding: The public abstract reports improvement after a saddle-angle intervention in a symptomatic cycling-club group. It does not validate OpenBikeFit or a universal tilt. Specific full-text percentages or angle recipes are not adopted from this abstract.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 10597848 · DOI 10.1136/bjsm.33.6.398
Open source
Husband S.P., Wainwright B., Wilson F. et al. (2024). Cycling position optimisation - a systematic review of the impact of positional changes on biomechanical and physiological factors in cycling. Journal of Sports Sciences, 42(15):1477–1490.
systematic review
Registry finding: The review screened 16,578 records and analysed 47 studies, with substantial quality and representation limits. It found no clear recommendations for crank length, handlebar height, Q factor or cleat position. This does not validate the app's particular formulas or every saddle-width rule.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 39285616 · DOI 10.1080/02640414.2024.2394752
Open source

Evidence topic

Cockpit and geometry

Reach, drop and the trade-off between aerodynamics and tolerance.

Back to topics

Claim 1 of 1 in this topic

Reach and drop are a tolerance–aerodynamics trade-off

Directional evidence

A lower, flatter position can reduce aerodynamic drag while increasing physiological cost and the mobility demand on the rider. There is no evidence-backed universal handlebar-drop target in millimetres.

Evidence, limits and sources

Why this grade

Gnehm compared a measured metabolic change with expected aerodynamic savings in 14 elite male racers. Fintelman measured physiology and frontal area in 19 trained male cyclists. Neither protocol establishes a guaranteed watt saving or a universal millimetre target.

Grade meaning: Research supports the direction of an effect, but not one universal target for every rider.

Where OpenBikeFit uses it

Bike fit calculatorProduces a cockpit range from riding intent and rider inputs, then labels it as a starting hypothesis to validate under load.
Bike fit learning hubExplains why a race-oriented position and an all-day position can rationally prioritize different outcomes.
Bike geometry comparatorKeeps frame stack/reach as raw signed coordinates and explicitly refuses to turn them into a rider-fit score.
Cockpit reach and drop calculatorCalculates component geometry as signed coordinates while refusing to convert the result into a universal rider-fit target.

Limitations

Wind-tunnel or laboratory positions do not capture every outdoor speed, surface, duration or handling demand.
Aero benefit depends on whether the rider can sustain the position and continue to produce useful power.
A frame's stack and reach describe the bicycle, not the rider's mobility, control or symptom response.

Sources mapped to this claim

3 sources

Gnehm P., Reichenbach S., Altpeter E., Widmer H., Hoppeler H. (1997). Influence of different racing positions on metabolic cost in elite cyclists. Medicine & Science in Sports & Exercise, 29(6):818–823.
peer-reviewed
Registry finding: Fourteen elite male racers were tested in three positions without outdoor wind resistance. The paper compared an estimated metabolic power cost with expected aerodynamic savings; it did not measure a guaranteed 100 W saving for a rider.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 9219211 · DOI 10.1097/00005768-199706000-00013
Open source
Fintelman D.M., Sterling M., Hemida H., Li F.-X. (2015). The effect of time trial cycling position on physiological and aerodynamic variables. Journal of Sports Sciences, 33(16):1730–1737.
peer-reviewed
Registry finding: Nineteen trained male cyclists tested five torso-angle conditions; physiological variables and frontal area were measured. Frontal area estimated drag rather than directly measuring every outdoor aerodynamic outcome. No universal handlebar-drop value follows.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 25658151 · DOI 10.1080/02640414.2015.1009936
Open source
Husband S.P., Wainwright B., Wilson F. et al. (2024). Cycling position optimisation - a systematic review of the impact of positional changes on biomechanical and physiological factors in cycling. Journal of Sports Sciences, 42(15):1477–1490.
systematic review
Registry finding: The review screened 16,578 records and analysed 47 studies, with substantial quality and representation limits. It found no clear recommendations for crank length, handlebar height, Q factor or cleat position. This does not validate the app's particular formulas or every saddle-width rule.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 39285616 · DOI 10.1080/02640414.2024.2394752
Open source

Evidence topic

Crank length

Power, joint motion and what changes when the crank gets shorter.

Back to topics

Claim 1 of 1 in this topic

Crank length changes joint motion more clearly than power

Directional evidence

Across the broad crank-length ranges studied, maximal power is comparatively robust when cadence is optimized. Shorter cranks can reduce peak hip and knee flexion, which may matter more to fit than a promised power gain.

Evidence, limits and sources

Why this grade

Power studies found small differences across very large crank-length changes and stable joint-specific power distribution when cadence was optimized. A smaller-change study found no efficiency or heart-rate benefit, but did find more hip and knee flexion with a longer crank.

Grade meaning: Research supports the direction of an effect, but not one universal target for every rider.

Where OpenBikeFit uses it

Bike fit calculatorFrames crank length as a clearance and joint-motion choice, not a deterministic wattage formula.
Bike fit learning hubConnects crank choice to cadence, hip closure and the rest of the position instead of isolating one component.
Crank length change assistantShows exact component and saddle geometry deltas while keeping joint-angle and performance effects directional, not promised.

Limitations

Results from maximal or acute laboratory tests do not answer every endurance, adaptation or terrain question.
The practical effect of a crank change depends on simultaneous saddle-height and fore-aft adjustments.
A shorter crank does not guarantee pain relief or improved power for a specific rider.

Sources mapped to this claim

3 sources

Martin J.C., Spirduso W.W. (2001). Determinants of maximal cycling power: crank length, pedaling rate and pedal speed. European Journal of Applied Physiology, 84(5):413–418.
peer-reviewed
Registry finding: Sixteen trained cyclists tested 120–220 mm cranks. Maximum power ranged from 1149 to 1194 W, with significant differences between some lengths. Cadence and pedal speed mattered; these results do not establish one length or guarantee equal power for every rider.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 11417428 · DOI 10.1007/s004210100400
Open source
Barratt P.R., Korff T., Elmer S.J., Martin J.C. (2011). Effect of crank length on joint-specific power during maximal cycling. Medicine & Science in Sports & Exercise, 43(9):1689–1697.
peer-reviewed
Registry finding: Fifteen trained cyclists tested 150–190 mm cranks. Relative joint powers did not significantly differ at optimized cadence, but some differences appeared at fixed 120 rpm. The finding is conditional, not a universal no-effect claim.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 21311357 · DOI 10.1249/MSS.0b013e3182125e96
Open source
Ferrer-Roca V. et al. (2017). Acute effects of small changes in crank length on gross efficiency and pedalling technique during submaximal cycling. Journal of Sports Sciences, 35(14):1328–1335.
peer-reviewed
Registry finding: Twelve amateur road cyclists tested their preferred length and +/-5 mm at fixed cadence and three workloads. Gross efficiency and heart rate did not significantly differ, while some joint-motion measures did. This acute protocol is not a personal crank-length prescription.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 27484153 · DOI 10.1080/02640414.2016.1215490
Open source

Evidence topic

Cleats and contact points

Foot position, saddle width and pressure at the hands and saddle.

Back to topics

Claim 1 of 2 in this topic

Cleat fore-aft should prioritize tolerance, not a power myth

Directional evidence

Anterior–posterior foot position did not significantly change oxygen uptake in the cited 11-cyclist fixed-cadence/workload protocol. That finding does not prescribe a personal cleat position, establish injury prevention or promise free power.

Evidence, limits and sources

Why this grade

The actual Van Sickle/Hull abstract describes a specific economy test, not all riding conditions. Silberman's publication identity was verified, but its full text and fitting landmarks were not read in this audit and are not used here as independent substantiation.

Grade meaning: Research supports the direction of an effect, but not one universal target for every rider.

Where OpenBikeFit uses it

Bike fit calculatorShows an app cleat-position convention separately from the study's limited economy observation; it does not assess symptoms or verify cleat installation.
Reversible cleat setup assistantRequires the rider to choose one axis, mark the baseline and compare one small trial without claiming a diagnostic or performance outcome.

Limitations

One economy outcome does not settle sprinting, injury risk, stability or every cleat system.
Fore-aft position is only one cleat variable; rotation, stance width and shoe support can also matter.
Numbness or focal pain should not be dismissed simply because an efficiency study found no difference.

Sources mapped to this claim

2 sources

Van Sickle J.R., Hull M.L. (2007). Is economy of competitive cyclists affected by the anterior-posterior foot position on the pedal?. Journal of Biomechanics, 40(6):1262–1267.
peer-reviewed
Registry finding: Eleven competitive cyclists tested three foot-attachment positions at a fixed cadence and workload near 90% of ventilatory threshold. Oxygen uptake did not significantly differ in that protocol; injury prevention and a universal cleat target were not established.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 16901493 · DOI 10.1016/j.jbiomech.2006.05.026
Open source
Silberman M.R., Webner D., Collina S., Shiple B.J. (2005). Road bicycle fit. Clinical Journal of Sport Medicine, 15(4):271–276.
peer-reviewed
Registry finding: Bibliographic identity of this clinical review was checked. PubMed exposes no abstract and the original text was not inspected in this audit; specific fitting landmarks or outcome claims are not asserted from that record alone.
Bibliographic identity only · 14 October 2026
NLM bibliographic identity checked; no public abstract or original text inspected.
PMID 16003043 · DOI 10.1097/01.jsm.0000171255.70156.da
Open source

Claim 2 of 2 in this topic

Saddle-width guidance stays provisional

Evidence uncertain

OpenBikeFit does not present an exact saddle width derived from height or inseam as evidence-backed. Contact-point guidance remains a starting hypothesis that needs a real measurement and an on-bike pressure check.

Evidence, limits and sources

Why this grade

Neither the identified broad position review nor the publisher's conference abstract establishes the app's body-dimension-to-width allowances. The conference abstract is not a full clinical validation report; missing evidence remains missing.

Grade meaning: The available evidence is too limited or indirect for a confident product rule, so the product exposes the uncertainty.

Where OpenBikeFit uses it

Bike fit calculatorLabels saddle-width output as provisional and directs the rider to measure and verify the contact point instead of trusting body height alone.
Sit-bone saddle width assistantRequires repeatable physical sit-bone impressions before showing a convention-labelled starting range.

Limitations

Saddle shape, padding, riding posture and pelvic rotation change where pressure is carried.
A width recommendation cannot diagnose numbness, skin injury or perineal symptoms.
The absence of strong consensus is a reason for caution, not proof that width never matters.

Sources mapped to this claim

2 sources

Husband S.P., Wainwright B., Wilson F. et al. (2024). Cycling position optimisation - a systematic review of the impact of positional changes on biomechanical and physiological factors in cycling. Journal of Sports Sciences, 42(15):1477–1490.
systematic review
Registry finding: The review screened 16,578 records and analysed 47 studies, with substantial quality and representation limits. It found no clear recommendations for crank length, handlebar height, Q factor or cleat position. This does not validate the app's particular formulas or every saddle-width rule.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 39285616 · DOI 10.1080/02640414.2024.2394752
Open source
Castilla Pikaza A., Iriberri J. (2025). Injuries caused by poor biomechanical fit in cycling: a narrative review. Journal of Science and Cycling, Science and Cycling Conference 2025 abstract.
conference abstract
Registry finding: The publisher presents a conference abstract describing a review of biomechanical injury literature. It is not a full clinical validation report, a causal map for a rider, or evidence that this app should personalize from symptoms.
Named webpage checked · 14 October 2026
Publisher identity and conference abstract read. No complete review text or individual clinical/causal outcome validated.
Open source

Evidence topic

Camera measurement

How static and dynamic angles differ, and where 2D video stops.

Back to topics

Claim 1 of 2 in this topic

Dynamic video is not interchangeable with a static angle

Supported reference

Static goniometry, dynamic 2D and 3D observations are protocol-specific. The calculator's +5° band shift is an app convention, not a universal correction measured for this phone-based system.

Evidence, limits and sources

Why this grade

Ferrer-Roca compared anthropometric and 2D dynamic approaches. Fonda compared instruments in 11 cyclists and proposed a 2.2° correction for that 2D/3D protocol. The studies do not calibrate MediaPipe or establish a universal +5° mapping.

Grade meaning: Relevant research supports the stated literature context. This grade does not validate the app's derived numbers, coefficients or an individual prescription.

Where OpenBikeFit uses it

Live camera fitUses a dynamic reference and presents measurement confidence so the rider can repeat a poor capture instead of treating it as truth.
Camera fit demoMakes the measurement workflow inspectable before a rider relies on it for an adjustment.

Limitations

Two-dimensional video cannot fully represent rotation or movement outside the camera plane.
Occlusion, loose clothing, lens position and landmark placement can reduce measurement quality.
The camera result is a fit-screening input, not medical imaging or a clinical diagnosis.

Sources mapped to this claim

2 sources

Ferrer-Roca V., Roig A., Galilea P., García-López J. (2012). Influence of saddle height on lower limb kinematics in well-trained cyclists: static vs. dynamic evaluation in bike fitting. Journal of Strength and Conditioning Research, 26(11):3025–3029.
peer-reviewed
Registry finding: The study compared anthropometric and 2D dynamic approaches and reported disagreement with its chosen references. Its regression and 30–40° context are protocol-specific, not OpenBikeFit calibration or a universal static-to-dynamic offset.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 22190163 · DOI 10.1519/JSC.0b013e318245c09d
Open source
Fonda B., Sarabon N., Li F.-X. (2014). Validity and reliability of different kinematics methods used for bike fitting. Journal of Sports Sciences, 32(10):940–946.
peer-reviewed
Registry finding: Eleven cyclists were measured with 3D cameras, high-speed 2D video and an electrogoniometer. The reported 2.2° correction belongs to that 2D-versus-3D protocol; it is not a universal +5° rule or calibration of a MediaPipe phone estimate.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 24499342 · DOI 10.1080/02640414.2013.868919
Open source

Claim 2 of 2 in this topic

Repeatability matters more than one convenient frame

Directional evidence

A useful camera result should recur across pedal cycles and a controlled capture. A single favourable frame is too fragile to justify a confident fit change.

Evidence, limits and sources

Why this grade

Bike-fit method research explicitly evaluates validity and reliability, not just whether an angle can be drawn. OpenBikeFit translates that principle into repeated capture and visible confidence rather than hiding measurement quality.

Grade meaning: Research supports the direction of an effect, but not one universal target for every rider.

Where OpenBikeFit uses it

Recording agreement checkRequires independent takes of one unchanged setup to agree before concrete hardware advice is unlocked.

Limitations

Repeatability can reproduce a systematic setup error, so a stable result is not automatically an accurate one.
Confidence in landmark tracking is not the same as confidence that a position will be comfortable.
A controlled indoor capture may not reproduce posture under outdoor fatigue, climbing or high power.

Sources mapped to this claim

1 source

Fonda B., Sarabon N., Li F.-X. (2014). Validity and reliability of different kinematics methods used for bike fitting. Journal of Sports Sciences, 32(10):940–946.
peer-reviewed
Registry finding: Eleven cyclists were measured with 3D cameras, high-speed 2D video and an electrogoniometer. The reported 2.2° correction belongs to that 2D-versus-3D protocol; it is not a universal +5° rule or calibration of a MediaPipe phone estimate.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 24499342 · DOI 10.1080/02640414.2013.868919
Open source

Evidence topic

Symptoms and safety

Why health concerns and retired symptom inputs remain outside this educational scope.

Back to topics

Claim 1 of 1 in this topic

Health concerns are outside this product's decision scope

Fitter convention

OpenBikeFit does not collect symptom details or use them to select a bicycle-adjustment direction. Retired calculator flags are discarded; clinical publications do not make this educational product a health decision-maker.

Evidence, limits and sources

Why this grade

Akuthota studied nerve-conduction outcomes in 14 participants after a tour, not a drop/reach treatment rule. The conference abstract and unread clinical-review text do not establish individual causation. The product scope and actual input handling remain independent boundaries.

Grade meaning: An explicitly labelled app or practitioner convention, not a scientifically established individual target or permission to modify a bicycle.

Where OpenBikeFit uses it

Bike fit calculatorAccepts no symptom field and discards legacy symptom flags before calculating all nine metrics. Health details do not personalize results.
Bike fit learning hubExplains technical references and measurement limits, not symptom-based diagnosis or treatment.

Limitations

Associations between fit and symptoms do not prove that bicycle position is the only cause.
Sudden, severe, progressive or persistent symptoms require appropriate professional assessment.
Changing several variables at once makes it harder to identify what helped or made the problem worse.

Sources mapped to this claim

3 sources

Castilla Pikaza A., Iriberri J. (2025). Injuries caused by poor biomechanical fit in cycling: a narrative review. Journal of Science and Cycling, Science and Cycling Conference 2025 abstract.
conference abstract
Registry finding: The publisher presents a conference abstract describing a review of biomechanical injury literature. It is not a full clinical validation report, a causal map for a rider, or evidence that this app should personalize from symptoms.
Named webpage checked · 14 October 2026
Publisher identity and conference abstract read. No complete review text or individual clinical/causal outcome validated.
Open source
Silberman M.R., Webner D., Collina S., Shiple B.J. (2005). Road bicycle fit. Clinical Journal of Sport Medicine, 15(4):271–276.
peer-reviewed
Registry finding: Bibliographic identity of this clinical review was checked. PubMed exposes no abstract and the original text was not inspected in this audit; specific fitting landmarks or outcome claims are not asserted from that record alone.
Bibliographic identity only · 14 October 2026
NLM bibliographic identity checked; no public abstract or original text inspected.
PMID 16003043 · DOI 10.1097/01.jsm.0000171255.70156.da
Open source
Akuthota V., Plastaras C., Lindberg K., Tobey J., Press J., Garvan C. (2005). The effect of long-distance bicycling on ulnar and median nerves: an electrophysiologic evaluation of cyclist palsy. American Journal of Sports Medicine, 33(8):1224–1230.
peer-reviewed
Registry finding: Fourteen participants were assessed before and after a six-day tour. Some measured nerve-conduction outcomes changed; this observational protocol does not identify one cause or establish a drop/reach/grip adjustment to treat an individual symptom.
Identity + abstract checked · 14 October 2026
NLM identity and public abstract checked; full text and app validation not established.
PMID 16000656 · DOI 10.1177/0363546505275131
Open source

Product decision rule

Range, confidence, reversible change

Research context, app assumptions and actual measurements remain separate. A stronger source does not validate a derived app coefficient or a personal adjustment. Conventions stay labelled, and missing evidence stays visible rather than becoming a more precise-looking number.

What this page does not claim

It does not certify that a calculator result is an individual optimum.
It does not collect symptoms or use output for a health assessment, safety-to-ride decision, care recommendation or health prediction.
It does not treat publication type as proof that every derived product rule is strong.

Put the method to work

Start with a transparent calculation, record the result on the bicycle and change one mechanical variable at a time. This workflow is only for adults without an active health or injury concern; it does not accept health details.

Open the calculator Try live camera fit Browse bike-fit guides

Evidence and limits behind an OpenBikeFit analysis

The analysis keeps three layers separate: measurements from the bike, published reference ranges and repeated 2D camera estimates.

Use the registry below to inspect every active claim, its evidence strength, where it changes the product and where the evidence stops. Population research never becomes a promise about one rider.

What the calculator assumes — and does not measure

Historical ratio

0.883 × inseam in mm

This gives the raw LeMond reference. It does not measure knee motion, segment lengths or an installed bicycle.

App corrections

(175 − crank mm) − 4 mm

The 175 mm baseline and fixed −4 mm term are app conventions, not a measurement of your pedal/shoe assembly. The full tool may estimate the crank term when no current length was entered.

App angle-band approximation

(30 − band angle) × 0.0022 × inseam mm

The angle is a selected reference-band argument, not your measured knee angle. No cited paper was established as validating the app-specific coefficient or its inseam-to-height conversion.

Fictional arithmetic, not a rider measurement

Source identity is a check, not product validation

Hamley E.J., Thomas V. (1967) · Physiological and postural factors in the calibration of the bicycle ergometer

Reported source type: peer-reviewed · Journal of Physiology, 191:55–56P

Bibliographic identity only · 14 October 2026

NLM bibliographic identity checked; no public abstract or original text inspected.

PMID 6050117

Historical bibliographic reference for the 109%-of-inseam convention. The indexed record has no abstract; the original communication was not inspected in this audit. The app's endpoint conversion is a separate model assumption.

Open this named source — new tab

LeMond G., Gordis K. (method: C. Guimard) (1987) · Greg LeMond's Complete Book of Bicycling

Reported source type: convention · Putnam, 1987 edition (ISBN 0399132295)

Catalog identity only · 14 October 2026

The 1987 Putnam edition is confirmed by a library catalog. Calculation pages, 175 mm assumptions and shoe corrections were not inspected.

Historical book reference associated with the 88.3%-of-inseam convention. A catalog confirms the 1987 Putnam edition, not the calculation pages. The app's 175 mm crank baseline and fixed -4 mm term are not verified findings from this book.

Holmes J.C., Pruitt A.L., Whalen N.J. (1994) · Lower extremity overuse in bicycling

Reported source type: peer-reviewed · Clinics in Sports Medicine, 13(1):187–205

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 8111852

Clinical review of overuse in cycling. Its public abstract discusses repetition and cyclist/bicycle factors; it does not expose a validated inseam-to-angle conversion or the app's coefficient. No clinical instruction is inferred here.

Open this named source — new tab

Peveler W.W. (2008) · Effects of saddle height on economy in cycling

Reported source type: peer-reviewed · Journal of Strength and Conditioning Research, 22(4):1355–1359

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 18545167 · DOI 10.1519/JSC.0b013e318173dac6

In 15 participants (5 cyclists and 10 noncyclists), oxygen uptake differed between the tested measured-angle and inseam-based conditions. This protocol does not validate an app-specific formula or an individual outcome.

Open this named source — new tab

Peveler W.W., Green J.M. (2011) · Effects of saddle height on economy and anaerobic power in well-trained cyclists

Reported source type: peer-reviewed · Journal of Strength and Conditioning Research, 25(3):629–633

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 20581695 · DOI 10.1519/JSC.0b013e3181d09e60

In 11 trained male cyclists, measured-angle conditions and 109%-of-inseam conditions differed; 73% of the latter were outside the study's 25–35° reference. This is one sample, not an app failure rate or a universal target.

Open this named source — new tab

Bini R., Hume P.A., Croft J.L. (2011) · Effects of bicycle saddle height on knee injury risk and cycling performance

Reported source type: systematic review · Sports Medicine, 41(6):463–476

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 21615188 · DOI 10.2165/11588740-000000000-00000

Review of 62 references with conflicting methods, small samples and limited injury evidence. It discusses a measured knee-angle approach; it does not validate OpenBikeFit's anthropometric conversion, coefficient or an individually safe position.

Open this named source — new tab

Ferrer-Roca V., Roig A., Galilea P., García-López J. (2012) · Influence of saddle height on lower limb kinematics in well-trained cyclists: static vs. dynamic evaluation in bike fitting

Reported source type: peer-reviewed · Journal of Strength and Conditioning Research, 26(11):3025–3029

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 22190163 · DOI 10.1519/JSC.0b013e318245c09d

The study compared anthropometric and 2D dynamic approaches and reported disagreement with its chosen references. Its regression and 30–40° context are protocol-specific, not OpenBikeFit calibration or a universal static-to-dynamic offset.

Open this named source — new tab

Fonda B., Sarabon N., Li F.-X. (2014) · Validity and reliability of different kinematics methods used for bike fitting

Reported source type: peer-reviewed · Journal of Sports Sciences, 32(10):940–946

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 24499342 · DOI 10.1080/02640414.2013.868919

Eleven cyclists were measured with 3D cameras, high-speed 2D video and an electrogoniometer. The reported 2.2° correction belongs to that 2D-versus-3D protocol; it is not a universal +5° rule or calibration of a MediaPipe phone estimate.

Open this named source — new tab

Martin J.C., Spirduso W.W. (2001) · Determinants of maximal cycling power: crank length, pedaling rate and pedal speed

Reported source type: peer-reviewed · European Journal of Applied Physiology, 84(5):413–418

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 11417428 · DOI 10.1007/s004210100400

Sixteen trained cyclists tested 120–220 mm cranks. Maximum power ranged from 1149 to 1194 W, with significant differences between some lengths. Cadence and pedal speed mattered; these results do not establish one length or guarantee equal power for every rider.

Open this named source — new tab

Barratt P.R., Korff T., Elmer S.J., Martin J.C. (2011) · Effect of crank length on joint-specific power during maximal cycling

Reported source type: peer-reviewed · Medicine & Science in Sports & Exercise, 43(9):1689–1697

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 21311357 · DOI 10.1249/MSS.0b013e3182125e96

Fifteen trained cyclists tested 150–190 mm cranks. Relative joint powers did not significantly differ at optimized cadence, but some differences appeared at fixed 120 rpm. The finding is conditional, not a universal no-effect claim.

Open this named source — new tab

Ferrer-Roca V. et al. (2017) · Acute effects of small changes in crank length on gross efficiency and pedalling technique during submaximal cycling

Reported source type: peer-reviewed · Journal of Sports Sciences, 35(14):1328–1335

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 27484153 · DOI 10.1080/02640414.2016.1215490

Twelve amateur road cyclists tested their preferred length and +/-5 mm at fixed cadence and three workloads. Gross efficiency and heart rate did not significantly differ, while some joint-motion measures did. This acute protocol is not a personal crank-length prescription.

Open this named source — new tab

Ménard M., Domalain M., Decatoire A., Lacouture P. (2020) · Influence of saddle setback on knee joint forces in cycling

Reported source type: peer-reviewed · Sports Biomechanics, 19(2):245–257 · PubMed 29920153

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 29920153 · DOI 10.1080/14763141.2018.1466906

In ten cyclists across three large setback conditions, model-estimated tibiofemoral compression differed between forward and backward positions. The study did not establish a pain-specific adjustment direction or universal setback.

Open this named source — new tab

Bontrager K. (1998) · The Myth of K.O.P.S.

Reported source type: convention · Bicycle Guide (reprint: sheldonbrown.com)

Named webpage checked · 14 October 2026

Named practitioner reprint read, including dated author notes; not a controlled study or app calibration.

A practitioner critique of treating a gravity-based knee/pedal alignment as a universal biomechanical law. The reprint is an argument and explanation, not a controlled trial or validation of the app's setback bands.

Open this named source — new tab

UCI (2024) · UCI Technical Regulations, art. 1.3.013

Reported source type: convention · Union Cycliste Internationale

Original rules not reviewed · 14 October 2026

Historical registry entry. Complete currently applicable competition rules were not reviewed; this is not event eligibility or current legal approval.

Historical 2024 regulatory entry, not current event eligibility or fit evidence. This source audit did not inspect the complete currently applicable rulebook; use the exact event, category and date rather than this entry as permission.

Gnehm P., Reichenbach S., Altpeter E., Widmer H., Hoppeler H. (1997) · Influence of different racing positions on metabolic cost in elite cyclists

Reported source type: peer-reviewed · Medicine & Science in Sports & Exercise, 29(6):818–823

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 9219211 · DOI 10.1097/00005768-199706000-00013

Fourteen elite male racers were tested in three positions without outdoor wind resistance. The paper compared an estimated metabolic power cost with expected aerodynamic savings; it did not measure a guaranteed 100 W saving for a rider.

Open this named source — new tab

Fintelman D.M., Sterling M., Hemida H., Li F.-X. (2015) · The effect of time trial cycling position on physiological and aerodynamic variables

Reported source type: peer-reviewed · Journal of Sports Sciences, 33(16):1730–1737

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 25658151 · DOI 10.1080/02640414.2015.1009936

Nineteen trained male cyclists tested five torso-angle conditions; physiological variables and frontal area were measured. Frontal area estimated drag rather than directly measuring every outdoor aerodynamic outcome. No universal handlebar-drop value follows.

Open this named source — new tab

Van Sickle J.R., Hull M.L. (2007) · Is economy of competitive cyclists affected by the anterior-posterior foot position on the pedal?

Reported source type: peer-reviewed · Journal of Biomechanics, 40(6):1262–1267

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 16901493 · DOI 10.1016/j.jbiomech.2006.05.026

Eleven competitive cyclists tested three foot-attachment positions at a fixed cadence and workload near 90% of ventilatory threshold. Oxygen uptake did not significantly differ in that protocol; injury prevention and a universal cleat target were not established.

Open this named source — new tab

Salai M., Brosh T., Blankstein A., Oran A., Chechik A. (1999) · Effect of changing the saddle angle on the incidence of low back pain in recreational bicyclists

Reported source type: peer-reviewed · British Journal of Sports Medicine, 33(6):398–400

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 10597848 · DOI 10.1136/bjsm.33.6.398

The public abstract reports improvement after a saddle-angle intervention in a symptomatic cycling-club group. It does not validate OpenBikeFit or a universal tilt. Specific full-text percentages or angle recipes are not adopted from this abstract.

Open this named source — new tab

Akuthota V., Plastaras C., Lindberg K., Tobey J., Press J., Garvan C. (2005) · The effect of long-distance bicycling on ulnar and median nerves: an electrophysiologic evaluation of cyclist palsy

Reported source type: peer-reviewed · American Journal of Sports Medicine, 33(8):1224–1230

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 16000656 · DOI 10.1177/0363546505275131

Fourteen participants were assessed before and after a six-day tour. Some measured nerve-conduction outcomes changed; this observational protocol does not identify one cause or establish a drop/reach/grip adjustment to treat an individual symptom.

Open this named source — new tab

Silberman M.R., Webner D., Collina S., Shiple B.J. (2005) · Road bicycle fit

Reported source type: peer-reviewed · Clinical Journal of Sport Medicine, 15(4):271–276

Bibliographic identity only · 14 October 2026

NLM bibliographic identity checked; no public abstract or original text inspected.

PMID 16003043 · DOI 10.1097/01.jsm.0000171255.70156.da

Bibliographic identity of this clinical review was checked. PubMed exposes no abstract and the original text was not inspected in this audit; specific fitting landmarks or outcome claims are not asserted from that record alone.

Open this named source — new tab

Husband S.P., Wainwright B., Wilson F. et al. (2024) · Cycling position optimisation - a systematic review of the impact of positional changes on biomechanical and physiological factors in cycling

Reported source type: systematic review · Journal of Sports Sciences, 42(15):1477–1490

Identity + abstract checked · 14 October 2026

NLM identity and public abstract checked; full text and app validation not established.

PMID 39285616 · DOI 10.1080/02640414.2024.2394752

The review screened 16,578 records and analysed 47 studies, with substantial quality and representation limits. It found no clear recommendations for crank length, handlebar height, Q factor or cleat position. This does not validate the app's particular formulas or every saddle-width rule.

Open this named source — new tab

Castilla Pikaza A., Iriberri J. (2025) · Injuries caused by poor biomechanical fit in cycling: a narrative review

Reported source type: conference abstract · Journal of Science and Cycling, Science and Cycling Conference 2025 abstract

Named webpage checked · 14 October 2026

Publisher identity and conference abstract read. No complete review text or individual clinical/causal outcome validated.

The publisher presents a conference abstract describing a review of biomechanical injury literature. It is not a full clinical validation report, a causal map for a rider, or evidence that this app should personalize from symptoms.

Open this named source — new tab

How to read the evidence grades