Rear-shock mounts: standard eyelets, trunnion and independent hardware

Rear-shock compatibility begins at the frame and its receiving mounts, not with the most attractive size pair in a catalogue. Preserve the frame model, generation, size, linkage configuration and exact instructions. Identify the installed shock independently. A frame family name is not sufficient if different variants use different arrangements. An aftermarket product may offer several mount and stroke versions under one model title; its title alone does not select the correct one.

Keep each source attached to the statement it supports. A frame manual may describe the required assembly, while a shock drawing identifies a product interface. A retail listing may omit both. Absence of a warning in a short listing is not permission. If the receiving system is undocumented or the part identity is uncertain, write unknown and stop the substitution question there. The guide can organise missing evidence but cannot replace the authority of the exact frame and component documentation.

At an eyelet mounting assembly, distinguish the transverse hardware width from the mounting bolt diameter. The width describes a span across named receiving or hardware faces. The diameter describes a circular section of a named bolt or receiving interface. Neither value determines the other. A label such as a width-and-diameter pair must be read in the order defined by its source; reversing the numbers or guessing the endpoints can produce an entirely different statement.

For a fictional interface record, write W=30 mm across explicitly named hardware faces and D=8 mm for the stated bolt-shaft diameter. These are independent observations, not actual part recommendations. Thirty minus eight equals 22 mm, but that subtraction has no established meaning as spacer width, bushing thickness, tolerance or clearance. Do not use it to invent a missing component. The SR SUNTOUR hardware glossary names width and bolt diameter separately within its system; retain that separation without copying its fitment table.

A shock can match a nominal mounting length while its reservoir, body, controls or other features occupy a different envelope. Clearance concerns the complete supported assembly through its relevant movement, not just the distance between two centres in a single static photograph. Frame flex, tyre and other moving parts add separate questions. A stationary visual gap does not prove every required condition will remain clear or determine an acceptable minimum clearance.

The SRAM drawing includes full-motion fitment considerations. Here it is a source for the existence of those independent checks, not a request to remove a spring, vent air or force the linkage through travel. That work belongs to an appropriate controlled service process with the exact instructions. Do not mark a whole assembly compatible because the drawing’s length line matches a catalogue number. If the motion envelope is not established, retain it visibly as not checked.

A useful question to the manufacturer names the current frame configuration, exact current and proposed shock variants, both mount arrangements, their documents and the unresolved interface or clearance issue. It does not need rider contact or health details in a public tool. RockShox’s compatibility FAQ separates dimensions, hardware and tune and directs the frame requirements to the appropriate authority. Preserve that scope instead of asking a generic question about whether a brand fits.

The free blank worksheet offers reference and question spaces, not a dedicated assembly approval field. Use supplementary technical notes in your own controlled workflow and keep missing evidence explicit. Continue to the stroke-versus-wheel-travel guide before interpreting any proposed capacity change. A properly named mount record reduces ambiguity; it does not authorise a swap, suggest an adapter or certify that a bicycle is safe to ride. No pressure, torque or installation choice is supplied here.