The bonded aluminium insert at each end of the rear tie rod tube.
Transfers axial load from the rod end thread into the composite tube through the adhesive bond. Minimum insert length is 2 x diameter to maintain the ideal slenderness ratio.
No part-specific design process is documented. The Rods subsystem design process applies: 1. Take the axial load in each rod from the HyperWorks load path study. CR26I front tie rod 390 lb over 13.67 in, rear tie rod 95 lb over 10.72 in, rear pushrod 1208 lb over 8.1875 in. 2. Run the carbon component calculator for every available Rockwest part number: it returns tensile, compressive and buckling factors of safety, estimated weight and price against inputs of load, length and target buckling FoS. 3. Size the insert: the calculator returns insert diameter, required length and adhesive factor of safety from tensile strength, load, required area and a minimum L/D ratio. Minimum insert length is 2 x diameter, which maintains the ideal slenderness ratio. 4. Select adhesive. DP420 at 4500 psi listed shear strength was chosen over ET5401 (2900 psi) and EA9460 (3500 psi) because it is already on hand and the required quantity is about 60 g. 5. Manufacture: cut to length with a diamond blade Dremel wheel, surface prep with IPA and sanding, bond at a 0.005 in gap using 0.0049 in silica bond gap controller with a 0.010 in clearance fit on insert diameters, cure 24 hours at room temperature under static pressure. 6. Proof test the manufactured parts: tensile to 1.5 FoS and compressive to 1.5 FoS, pass/fail.
Machined, then bonded or welded into the parent part.
Aluminium, bonded with 3M DP420.
Adhesive tear-out is the failure mode seen in validation testing. One test sample failed low because its insert was shorter than designed, which is a manufacturing control problem rather than a design problem.
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_RearTieRodInsert (mm): 5.1, 31.8, 10.8, 17.4 Source: Cost report drawings: CR26i/Suspension/Competition/Cost Report Drawings/Suspension and Shocks/Rear Tie Rod Assembly/CR25_SUS_RearTieRodInsert.pdf Quantity per car, as costed: 2
Nothing in CrimsonStorage covers these yet.