I was checking over the "Cricket Car" and noticed that the inside of the rear tires are definitely wearing on the inside tread. I put the protractor on the wheel and it looks like I have about 4 degrees of -camber on the rear wheels after towing to Carlisle and all the driving there.
I understand that technically there is no camber adjustment but something is definitely worn somewhere.
Any thoughts?
Thanks, Michael
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Is your car swing axle or irs?
Sorry Al, the most important spec..IRS
You might check "Toe In" on that rear end..... I've seen tires killed in less than 5,00mi. because of this....
How low is your car? Irs doesn't go through the wild camber changes that the swing axle suspension does but I believe there is some change as the suspension compresses (or the spring plate is adjusted so the rear is lowered); I think it goes into a couple of degrees more of -camber, but don't know how much. I remember reading once (on the Samba, I think) that to lower an irs car properly you should swap the rear trailing arms from side to side, but this is fairly involved, as it requires you to remove and then weld the shock mounts back on. I have heard of the bushing in the front/pivot end of the trailing arm affecting alignment settings when it's worn, so maybe start there?
That and Leon's recommendation to check the toe-in; I don't know what else to tell you, other than to check that the trailing arms aren't bent. I have heard of them twisting under heavy off-road use, but never in a street car. Al
Is it true that Vintage Speedsters uses only swing axles? That's what I have and I use a camber compensator that seems to keep the camber straight up rather than
letting the rear wheels do their "own thing". I'm on year 3 and about 8,000 on my Verdesteins and they still look new with no discernable wear. I guess I lucked out.
I believe that's true, Jack. Don't they use a custom frame? The camber compensator really does a good job taming a swingaxle; the trade off is a little less suspension travel.
The IRS rear camber is going to change somewhere on the order of 1 degree per inch of suspension travel. So that can account for some of it depending on how much the car has been lowered.
The IRS trailing arm flip is typically only necessary for really low suspension heights (5+ inch drops). The arms have about 1.5 degrees of built-in negative camber so flipping them reduces the negative camber by about 3 degrees. Lots of work to do it, though.
There is some small adjustment of camber by changing the up and down angle of the spring plate vs the trailing arm mount. However, that's not going to have 4 degrees of adjustment.
The most likely cause of excessive negative camber, if it hasn't been lowered too much, is worn inner or outer bushings in the trailing arm mounts. This lets the arm twist in its mounts too much and causes excess camber.
Toe-in also increases as the suspension moves up and down, and if it's been lowered, there may not be enough adjustment left to get the toe back to stock. This will compound the tire wear due to the excess camber.
Assuming everything else checks out, then you can worry about the trailing arms themselves being bent and needing to be replaced.
IRS is an option on Vintage built cars. I have a had a lot of them and the red super widebody I'm selling right now has IRS.
Thanks for the heads up, Troy. I was under the impression that Vintage only built swingaxle cars, but didn't know definitively.
And thanks for the irs suspension info, Justin.
Al--well we got to the bottom of the Vintage axle deal thanks to Troy.
You mentioned that VS uses a custom frame and that is sorta true. They start out with a pan (like the original Speedsters used) and weld a 2x4 steel perimeter around the outer edge of the pan. You can see it inside the car along the edge of the floor. In the old days if you jacked up one side of a Speedster replica, the doors would jam because of the flex of the pan, With the improved pan/frame Vintage developed, that is no longer true. I don't if the CMCs and the original pan- based IMs had that steel perimeter or not.
Driving over railroad tracks I don't sense any flex at all in my car. The CSP beam braces also help a lot in the solidness of my car and made a pretty big improvement to the overall ride--especially when I go over bumps or rr tracks.
Thanks for the feedback guys. I did lower the rear a little but the camber had been alright as I put about 1000 miles on it before the Carlisle trip so I think I'll start with the bushings.
Any suggestions on bushing material/manufacture.
Thanks
If you can find them, OEM Volkswagen parts..... MHO....
