24/08/2026
MP4/6 front suspension design calculations..
Another page of old notes found buried in my garage from 1990/1991 from when I was designing the MP4/6 front suspension.
This sheet shows some initial rough hand calculations for when I was sizing the push-rod, itself a compression member that also had to withstand buckling. You'll see that this sheet only initially considers the vertical load (bump load) at the wheel. Cornering and braking loads would be considered independently, then everything added together.
The technique was to give the bump load a value of 1.0 unit then resolve the push-rod load, and other links' loads, in terms of this unit load.
Note that with spherical joints in the suspension members, all the vertical load at the wheel has to be resisted/carried by the push-rod. Furthermore, with the push-rod at an angle, it's the vertical component of the compression load in the push-rod that has to match the input vertical load at the wheel. The result of this single input also causes compression forces in the upper wishbone and tensile forces in the lower wishbone. When cornering and braking loads are analysed independently, the maximum and minimum loads in each suspension member can be determined and, with the material chosen (in this case SAE 4130 alloy steel) the cross section of each member calculated to ensure it will never break or buckle.
The MP4/6 saw us return to a push-rod layout for the front suspension, the first time since the MP4/3 in 1987. This was mainly due to the aero department wanting to narrow the chassis close to the driver's ankles meaning the spring/dampers hadcto go on the top of the monocoque.
For signed limited edition MP4/6 prints, email me at [email protected]
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