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copcars 10-21-2009 09:49 PM

32 roadster shimmy and shakin
hello folks...maybe someone can give me some advice and help with a problem with my new 32 roadster.I am NEWBY TO 32'S.... so hope my question doesn't sound stupid...Roadster is a downs glass body.Quality build with chrome drop axel,chrome hair pins and chrome steering components,stainless ididit colomn etc...don't know brand of steering rack and pinion or power steering...basic cross steer geometry........problem I am experiencing is a shimmy and a shake between 40mph and 65mph...has new goodyear eagle tires up front... did note some movement or slack in steering shaft joints etc but minimal. Does anyone have advice here and help to diagnose and resolve...would appreciate any help...thanks for your valuable can reach me on my cell 715-574-2100 Lee in wisc..

NEW INTERIORS 10-21-2009 09:59 PM

You need to check and see what degrees your king pins are set at.. did you make sure you didn't lose a weight off one of the wheels ??? May need to get them rebalanced..

A friend had one do that, And he reset the degree on the king pins. And put some better tires on front, and fixed the problem.. :)

Centerline 10-21-2009 10:09 PM

I'm no expert but it sounds to me like you may have a little "death wobble" going on. Check to make sure you have between 5 and 9 degrees of positive caster and proper toe for the tires you're using.

Borrowed this from an article in Street Rodder:

One of the most common mistakes when setting caster is making the adjustment while the chassis is not at ride height front and rear. Caster is the relationship of the axle to the ground, not the chassis. That means if it's set at 5 degrees positive with the frame sitting level on a jig, then the car is put on the ground with a 3 degree nose-down rake, the caster will be 2 degrees positive-and you'll be wondering why the car wanders all over the road.

Another thing that might also be part of your problem is tow in. Again borrowed from a Street Rodder article:

Most straight axle street rods are sensitive to toe adjustment, and this is another one that will be influenced by the type of tires being used. Radials require less toe in, 1/16 to a 1/8-inch is typical, bias ply tires require a little more, 1/8 to 3/16-inch is usually required.

NEW INTERIORS 10-21-2009 10:14 PM

Centerline is right..When I build a frame, I build it level, But I set it at 7* so when it's on the ground at ride height. with the rake of the car you will end up around 3* to 5* degrees.. You want it between 3* and 7* degrees..

Deuce 10-22-2009 05:58 AM

Both of these guys are dead on. :D

I always run 7 degrees and about 1/8 of a inch toe in.
When I first got my 32 roadster back on the highway in the late 80's ... I had a similar issue. I reset the front end to 7 degrees king pin lay back and 1/8 inch toe in and the issue disappeared.

Also too wide a tire on the front can cause problems. A rim with a lot of offset can also aggravate the issue.

Now both of my 32's rim a fairly small front tire with almost zero offset on the rims. Not a problem with either one ... over 50 thousand miles on the roadster and one summer on the 3W.

NEW INTERIORS 10-22-2009 09:41 PM

Thanks for bring up the toe in.. That's is also very important.. :thumbup:

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