27mm torsion bar adjustment question

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75evo
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27mm torsion bar adjustment question

Post by 75evo »

Does anyone know for 27mm torsion bars, if I adjust it by 1 spline at the lower a-arm, how many mm it would go down by? Trying to avoid having to adjust both sides of the torsion bars. Too much work.

Thanks

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Maurizio
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Re: 27mm torsion bar adjustment question

Post by Maurizio »

Why would that be different to any other torsion bar diameter?

Explanation:
The diameter of the torsion bar only influences the angular deformation of the bar due to a load.
The total number of teeth on the torsion bar determines how much degree you rotate the lower control arm per changed tooth.

If you are not nitpicking: the given load (weight of the car) doesn't change, by lowering the car.
So .. just do the math :lol:


1) 360 [deg] * 1 tooth / total amount of teeth = changed angle
2) Tan (changed angle) * lower control arm length = vertical moved mm of the wheel.

If you are really picky: the distance between upright lower ball joint <-> torsion bar center in the horizontal plane (let's say the road) is also changing a bit due to the rotation of the torsion bar.
Which changes the stiffness of the suspension = determined by angular stiffness of the torsion bar & arm length in the horizontal plane.
Shorter arm = stiffer suspension.


Enough confusion?!? :wall: :mrgreen:
Banned.. ? ;-) Daily donky.. ==> BMW 325d Image
E36M3 (3.0) Ringtool :twisted: ==> definitely BANNED!

AR 75 TS Ringtool '90, AR Spider 2000 veloce '79

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75evo
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Re: 27mm torsion bar adjustment question

Post by 75evo »

Thanks Makes sense. But only the a-arm is coming off, I don’t want to deal with splines on both ends. What a nightmare it was the last time.

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