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Classic VWs used torsion bars front and rear. I wondered if they might be applicable to a midi.

As usual, "yes, but."

The VWs used solid round rear bars with splined ends, from 22 to 25 inches long depending on the model. The aftermarket supplies bars of various rates suitable for single-seat sandrails up to loaded buses.

Downside: the bars are splined on the ends, and each end is different. The outer ends are the trailing arm pivots, and can be purchased, but I didn't find a source for the inners. Of course you could weld bracketry directly to the bars.


The VW has four torsion bars in front, two on each side, one for each trailing arm. They're stacks of flat strips arranged into square bundles. You'd have to make up square sockets for them to fit into, not a big deal. Unfortunately, while I found umpty-dozen suppliers for rear bars, I couldn't find any front bars, not even used ones on eBay. VW bits haven't been junkyardable around here for a long time.

I'm keeping them in mind, though. I still have the stick of 4140 steel I bought to make the bars for the first car, but even though various people claimed they used the stuff without need for heat treating, I've had niggling doubts.

The classis VW's used 2 front torsion bar "stacks" that are both constrained in the center of the tube. Take a look at some Formua Vee sites or dune buggy sites. These parts are still commonly available. http://dansperformanceparts.com/buggy/susp/buggysusp%20front.htmFor the front suspension, due to the reduced weight, FV's typically use only one of the stacks for springs. The center retension devise is redesigned to allow for adjustable ride wieght. The 2nd tube deletes the center retention device completely and instead of a stack, uses a steel rod with square blocks welded or brazed on the ends to fit the trailing arms. This 2nd "spring" is now reconfigured as the anti-sway bar.

Aha! The picture I found made it look like there were two short bars joined at the adjuster.

The link you posted shows the "front end adjusters" with the requisite square holes for $13 each and narrowed leaf sets for $100, stock width for $128.

You may have been looking at a front end setup for an off-road car. Many of them widen the front end by making longer torsion tubes with two anchor points in the center of each tube (four anchor points total), and each tube containing two half length leaf stacks.

In my view, torsion bars have a few negatives, the main one being there is no simple way to change the spring rate once you have built it.

As you will need to have shock absorbers anyway, far easier to just wrap a coil spring around the shock.

Coils are light, compact, easy to change, and readily available in a variety of lengths ands stiffness.
Why do things the hard way ?

Ahhhh but the VW torsion bars are diffferent. They are not made of a single bar/tube. They are composed of a stack of about 5-7 steel strips. The width and thicknesses can be changed or swapped out making an easily adjustable spring rate. If I want ~20% less spring weight, remove a strip. They do need to be individually greased up so that the individual strips can move against each other. The housing tube keeps the strip elements away from water and grime.

You are right about the simplicity of the coilovers. The problem is that the coilovers are expensive. Tradeoffs - tradeoffs - tradeoffs.

Coilovers have many packaging advantages. Unfortunately, the cost is higher than I like, unless I go for motorcycle take-off shocks from eBay.

That should work fine on a featherweight car, but my project will be a bit larger and a bit heavier than what most of you guys here are aiming for.
I am still at the initial mock up stage, but am using some old factory coil overs that originally came from Lotus and Jaguar to figure out my chassis pick up points, clearances, and geometry.
At a much later stage I will buy something really decent.
Shocks and tires are things where you mostly get what you pay for, and doing it really cheap may be false economy in the long run.

Does anyone want to save me a bunch of googling and put a image close up of this on this thread as a reference? This was all news to me and I thought I was pretty well informed.

The spline collars for the rear are on page 85.
http://www.denunzioracing.com/pdf/rearsusp.pdf

Oct 9, 6:31 PM Post:
viewtopic.php?f=36&t=11384&start=45

King pin spindle beams have square receivers. Ball joint beams have an extra leaf centered on top and bottom. It takes some creativity to reduce the stack without welding. One could grind the leafs narrower between the ends and the center to reduce the rate and keep the full stack tight in the receivers. I'm going to try keeping the full rate and adjusting the center position to set the ride height at mid-travel.

Easy with VW flat springs, just slide your fixing fixture up and down the length of them as well as adding/subtracting leaves. Allows you quite a substantial range of fast adjustments and ride heights.




http://lmgtfy.com/?q=Languid

Yo, Cheapracer-
I fell for it, clicked the link...

Good one!!!

Of course, if you could find an old Porsche 914 for a front-end donor, they have a very cool torsion bar design, with a pretty good front suspension already set up....

Sprint Cars and Midgets use Torsion Bars, based on the same principles, but are adjustable and changed out easily ...... http://www.world-sprintcar-guide.com/sp ... -bars.html
The bars can be bought @ differing spring rates for cheap ..... http://www.hoseheadsclassifieds.com/Cla ... ~57168.htm
and as far as coilovers go ..... http://www.hoseheadsclassifieds.com/Cla ... ~57771.htm
http://www.hoseheadsclassifieds.com/Cla ... ~58325.htm