Can I Cut Off Part of My Torsion Bar?

[adamrobbins2018]

I have a 70 VW bug that I am building in to a baja. I want to run bigger tires then 28's The rear torsion bar is sticking out and is keeping me from running a bigger tire. Can I cut off this part that is sticking out and cut a weld the cap back on? Will this hurt anything if I cut part of the torsion bar off?

[Bruce2]

No, it won't work.

[SCOTTRODS]

There are different Length Torsion bars, but I think you would have the short ones in a 70 model if the Frame/pan is the correct one. These cover pics should give you an idea of what's out there. Could be the enclosed ones are for Swing axle though... Just showing you there are different options out there... Who knows... maybe you can do it with the wrong stuff and make what you want work. People do it all the time. Swing axel torsion bars and plates and covers? Try Air-cooled.net... if you call and talk to John I bet he can give you some good advice.





These would probably do it with Coil over shocks -

[Ol'fogasaurus]

Assuming you are running IRS (If I remember correctly not everywhere in the world uses IRS for rear suspension) the limit in tire dia. is about 30" maybe, if you are lucky, 31". Its been a long time but as SCOTTRODS partially alluded to the shorter swing axle torsion bars may or may not work as I think the spring plates could be a problem for a couple of reasons. If you are still stock US '70 model, you should have double spring plates that were use up to sometime in mid-'71 ('69 and up was IRS). The difference in the bolt pattern to connect the spring plate to the matching trailing arm is different than the later IRS suspensions that use a slightly thicker but single spring plate per side.

Shortening torsion bars, especially welding them is a no! Remember that a torsion bar is one type of spring; they work similar to a coil spring by twisting to increase the ability to carry their loads. Heat alone can cause weakness in springs (heating the front coil springs used to lower cars this way... not a good idea!) much less disturbing the grain of the spring by cutting then welding which could take some of the working properties out of the torsion bar.

The spring plate SCOTTRODS posted is something I have seen used when going to coil-over shock absorbers. While they seem to hold up the spherical rod ends are not really designed for that kind of use especially if they are adjusted to be longer so that some of the threads end up in shear. I don't remember seeing one fail but I have seen them "disappear" in-lieu of a different but stronger setup. (for info) I think they might be helpful in a swing axle situation as they would help keep the spring place from twisting itself [IRS does the same thing but I don't thing it is as much].

(for what it is worth) There is a type of "overload" shock absorber that are used but not designed for what they are often used for; I don't recommend them. I don't use the commonly used term air-shocks here as there is another type of shock that is often used as an overload tool replacing the shocks that can have air added to them to make the suspension support more weight or to raise and lower the car. They can be very dangerous if their several weaknesses are not understood and used correctly; kind of like a air bag but so much worse. When I bought my blue buggy they came on the rear to keep the body away from the tires. I almost end-over-ended the buggy once when I got into some whoops at the bottom of a dune and the "air-shocks" got the buggy into a rhythm ending up with bouncing and I almost went head over; e.g., I did a wheelie but on my front tires. That is when I learned how to adjust the rear torsion bars.

Lee

My opinion is worth slightly less than you paid for it.

[Ol'fogasaurus]

I found the pix of the differences between the early and late IRS's. If you want I can post them.

Lee

[Ol'fogasaurus]

Pix of the two IRS training arm connection to the spring plate.

Difference between single and double spring plate 001.JPG

The two bottom holes seem to be the same, it is the upper holes that are different.

DSC03741.JPG

This shows the early spring plate ('69 to sometime in '71) that has two arms. The trailing arm connection mount is captured between the two spring plate arms where on the (sometime in) '71 and on is a single arm and just clamps to the spring plates with three bolt rather than the earlier 4 bolts connection.

Lee

[Bruce2]

The difference in the bolt pattern to connect the spring plate to the matching trailing arm is different than the later IRS suspensions that use a slightly thicker but single spring plate per side.

This comment piqued my interest. I just happen to have both types of spring plates in my garage now, so I measured them. The single plates are the same thickness as the double plates. Both 4mm.

[Ol'fogasaurus]

The difference in the bolt pattern to connect the spring plate to the matching trailing arm is different than the later IRS suspensions that use a slightly thicker but single spring plate per side.

This comment piqued my interest. I just happen to have both types of spring plates in my garage now, so I measured them. The single plates are the same thickness as the double plates. Both 4mm.

Thanks Bruce. I have been told severall times that they were different but never measured them even when I had both sets out. Like you I never every even thougth about it as I assumed those (more than one but less than 1000 ) who told me knew for sure.

Lee