Crimson Racing Wiki

Bump Stop

Subteam: SuspensionSubsystem: DampersAssembly: Shock AssemblyCars: CR25, CR26I, CR26E

Purpose

Set the minimum ride height so the aerodynamic devices cannot contact the track.

Function

An elastomer stop on the damper shaft that engages near the end of compression travel. Because it engages progressively rather than as a hard stop, it also acts as a very stiff spring in the last part of travel, which changes lateral load transfer distribution significantly.

Design Process

No part-specific design process is documented. The Dampers subsystem design process applies: 1. Kinematics sets wheel rates; spring rate follows from wheel rate and motion ratio. 2. Dyno the available dampers and select matched units by axle. 3. Set bump stop height from the aerodynamic minimum ride height and the worst-case heave and roll. 4. Tune on track using damper position data from the bellcrank rotary hall-effect sensors. 5. Read the traces for asymmetry between bump and rebound travel time, which is the practical indicator of over- or under-damping.

Analysis

LLTD across bump stop states: CR26I 39.55% front with no bump stops, 41.22% partial, 48.20% on bump stops only. CR25 42.87 / 43.88 / 48.04%. CR22 47.33 / 47.45 / 47.66%. Bump stop resolution is calculated from the damper position sensor resolution and error multiplied by the bump stop spring rate.

Full Material List

Elastomer.

Reoccuring issues

None recorded. This part has no entry in Knowledge_Transfer/Issue Logging/Fault Vault.xlsx, in either Issue Log.xlsx, in CR22/Issue Tracking/Shakedown 7-15-23.xlsx, or in any design review issue list found in CrimsonStorage or Box.

Still to document

Nothing in CrimsonStorage covers these yet.