CR21 naming for the rear ARB bearing holder.
A machined part providing the interface between the component and the structure, positioning it accurately enough that the designed geometry is what the car actually has.
No part-specific design process is documented. The ARB subsystem design process applies: 1. Take the roll rate targets and the LLTD range from vehicle dynamics. 2. Size the torsion bar. CR26I: AISI 4130, 0.5 in OD, 0.33 in ID, 68.12 lb-in/deg torsional stiffness, contributing 1160 lb-in/deg (96.7 lb-ft/deg) to roll rate at nominal. 3. Design the blade and set the drop link positions. Five settings give blade lengths from 4.43 in to 5.57 in and roll rate contributions from 113.8 down to 72 lb-ft/deg. 4. FEA the blade at each setting to confirm deflection and the resulting change in roll rate contribution (1.24% to 1.34% across the range). 5. Design retention: a machined square boss and bore to minimise backlash, a threaded stud for blade retention, and a transition-fit needle bearing for bar mounting. 6. Confirm the resulting LLTD range on the car.
Milled on the CNC.
Aluminium. From the cost report drawings and CAD: From the cost report drawings: Al-6061T6 (CR25_SUS_RearARBTubeMount); AL-6061T6 (CR26I_RearARBBearingHolder).
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.
CAD mass, CR22 master assembly: 0.011 lb (0.005 kg), 2 instances, 0.023 lb total. CG at X 87.09 in, Y -0.00 in, Z 3.48 in in vehicle coordinates. (CAD component: Bearing Holder Rear) Dimensions called out on the cost report drawings. These are the figures printed on the drawing, not a labelled specification; open the drawing itself for what each one refers to. CR25_SUS_RearARBTubeMount (as drawn): 25.40, 2.54, 44.45, 4.45, 17.46, 1.75, 15.88, 1.59, 14.48, 1.45 CR26I_RearARBBearingHolder (mm): 44.5, 15.9, 17.5, 14.5, 25.4 Source: SolidWorks mass model exports: CR22 (5 May 2024), CR25 (4 Jul 2025), CR26I (30 Jul 2025), CR26E (22 Mar 2026) | Cost report drawings: CR25/Suspension/Management-Comp/Cost Report/Drawings/Sus Shocks - Rear ARB Assembly/CR25_SUS_RearARBTubeMount.pdf; CR26i/Suspension/Competition/Cost Report Drawings/Suspension and Shocks/Rear ARB Assembly/CR26I_RearARBBearingHolder.pdf Quantity per car, as costed: 2
Nothing in CrimsonStorage covers these yet.