Torsion bars?

[formula]

I was helping a friend work on his truck the other day...and got to thinking...what's preventing torsion bars from being used in a performance application?

[Nate K]

All dodge trans-am cars from the 60s used torsion bars.

[Mean 69]

what's preventing torsion bars from being used in a performance application?

Nothing. The main issue is that the overwhelming majority of performance applications, in other words RACE CARS, use coil springs in a couple of specific diamters, etc, so parts are very easy to swap between different vehicles and are readily available.

A torsion bar is a coil spring that happens to be un-wound.

Mark

[MrQuick]

weight, weight and packaging.

[Mean 69]

When we pulled th t-bars out of my 68, the guys at the shop wanted to save them. Why? They ground down one end, and turned them into HUGE pry bars!

M

[Norm Peterson]

Packaging is part of it.

And it has different requirements. A beefier load-carrying control arm is likely, since the cantilever bending at the T-bar that its control arm experiences is about double what would exist in a control arm with the spring located near its midpoint in the same car. Relatively small-diameter tubular designs need not apply.

In addition, local reinforcement of the chassis against torsional loads where the T-bar plugs in is necessary, and the transfer of those loads into the overall chassis structure differs from that of coil spring arrangements (translation: retrofitting a T-bar suspension into a coil spring chassis is likely to be more difficult to do well than vice-versa). Not that this couldn't be used to some advantage, but you'd have to work up the basic structural arrangement of your chassis with this in mind from the get-go.

A minor point is that since a T-bar isn't readily compatible with stick axle RWD limits the general applicability somewhat.


Norm

[Bjkadron]

After reading this thread I've been thinking(I know... that's bad. but bear with me for a second).

The cons to a torsion bar are Packaging, weight, and trouble changing wheelrates.

Let me address each of these problems.

1. Packaging. If your going to build a new chassis than the packaging isn't that much of a problem. I just saw some pictures of a car getting built for "le carrea panamerica"(I think that's how you spell it) and they were using torsion bars.They also had a cool way of mounting them for stick axle use. I can see if I can find the link if you want to see it.

2. Weight. Ok. A steel bar is pretty heavy... But I've found lighter ones that were gun drilled/Hollow so you apparently can get them lighter(like hollow swaybars). And I had an even better Idea! Carbon fiber torsion tubes! Now I'm Not entirely sure this will work but I have done some "small tests" that show promise! I took a small carbonfiber tube and attached levers to the ends(so I could twist it easier) and twisted it to see how far it would go before it failed(disintegrated). Well so far I've twisted it past 100degrees(isn't that farther than a torsion bar twists?) before the ends that I glued on broke off(wrong glue). But the tube showed no signs of failing and was pretty stiff! It(the tube) was also Feather light so I think that would solve the weight problems. Input?

3.trouble changing wheelrates. Actually torsion bars are very easy to change the wheel rates on if you use a lever. all you have to do is change the length of the lever.


The pros of torsion bar style include, being able to change ride height and wheel weights easily and ease of adjusting spring rates.(depending on the method of attachment that is)

So really I don't see any reason why you couldn't use them for High performance.

[High Plains Mopars]

Preference.

Sprint cars have been using them for years.