Building a 27 t on an A frame but want to add antiroll bars front and rear. What or how do you figure out arm length needed on torsion type roll bars. Will be transverse in front with coilovers in rear Thanks in advance
We need pictures and a bunch more information and details for what you are trying to accomplish. Arm length will be dictated by component clearances and motion ratios of the suspension geometry. The longer the torsion bar, the lower the spring rate per degree of rotation.
Don’t you get the arm length to fit the situation, and adjust the strength of the unit by changing the diameter of the bar?
Arm length changes the leverage, which changes the roll characteristics. So you can have more or less response from the bar depending on your arm length.
There is a lot of math involved to calculate roll stiffness. You need the roll centre, and CGH to calculate weight transfer at a particular lateral acceleration This becomes "overturning moment" which equals bodyroll angle. For the ARB there is motion ratios involved [eg: how far inboard/outboard the arms insert] and then the arm length , ARB length and diameter. If you are "semi" mathematically challenged you can fix one end of the ARB and jack the other using scales. Then try different pivot points on the arm. You can also do this with 4 x jack stands on the frame and a jack/scale under a front wheel Understand if the front ARB [or total front roll stiffness] is too stiff you will get understeer or pushing The stiffest end always slides out first. Now the big question ???? Is this for racing or street comfort? Because these handling characteristics only happen at the limit of tyre adhesion [one end will "let go" first] If it is for a street cruiser you can safely go soft in the suspension and stiff in the ARB to keep the car level But if you go too stiff you will convert the suspension to a giant "mono" [or swing arm] with no compliance. Or the frame will flex instead I know of many examples of cars having stiffer front suspension and the driver "feels" the improvement. But put it on the track and the lap times were a lot slower.
My first thought on the Model A frame. But the OP needs to clarify if he plans on using a true "torsion" bar.
A plethora of tech. Here: https://www.google.com/search?q=ste...VK3WMKHfv2C2kQ_AUICSgB&biw=1280&bih=752&udm=2
My self on the 32 sedan I need to add a Torsion bar or Sway bar on Rear , On my pass A's & 32s all built same way no issue , but this 32 sedan built same way , has alot of body roll in rear , I am thinking it is because so much heaver from B pilar rearward .. So with is a better One over the other For Body Roll , Normal driving . Torsion or Sway ,, car sit's low With 2 inch rake .. Triangler 4 bar I have changed coils , set up now with 200 .
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