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Old 07-07-2021, 07:37 AM   #15 (permalink)
Autobahnschleicher
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Join Date: Apr 2021
Location: Germany
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Aerospyder - '00 Toyota MR2 Spyder
Team Toyota
90 day: 41.98 mpg (US)

Simme - '83 IFA Simson Suhl S51
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Quote:
Originally Posted by AeroMcAeroFace View Post
This is probably not best suited to the aerodynamics section, but it is here now.

But it obviously doesn't cancel out, because if it did then removing the spare wheel would make no difference. The inertia is reduced, there is less grip, both proportionally by the same amount because the tyre grip can be assumed to be linear.

I suppose the question is really, why does a small change in weight/downforce have a big effect on some cars, yet a negligible change in others?
And why doesn't the grip loss balance, less weight at the front, less grip at the front. The only explanation I can think of is weight transfer, cg height, moment of inertia, or maybe tyre pressures too high for the new weight.

To be clear, I don't believe that the sole cause of increased stability in Julian's case was a few kg of downforce, I believe that it is mostly to do with the centres of pressure moving further back, but I think he would disagree.
The ballance issues are due to the spring rates and stabilizer beeing wrong for that and my center of gravity moving even further behind the center of pressure.
Small changes are more noticeable if the change the ballance and the car is lightweight.
Tire grip is not perfectly linear indeed, I used it as an approximation.
The coefficient of friction drops a little with ground pressure.

Anyways, I'm not going into details of suspension setups because that's too much.
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