Caster Shim Dimensions

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Mar 28, 2002
Searched the archives, and could not find a post giving the dimensions of 2.5 and 4 deg shims.

Anyone have the depth of the edge at the thickest part, and the length?
I dont have it offhand but I have to ask why? Does it make a difference? NAPA sells the 2.5' shims is bronze. Real nice and cheap. WIll not crack. NAPA should be able to give you the details. The 2,5 and the 6 will be the exact same size except for the thickness difference
I have a 4" lift on my 40 and it does tend to wander on the road. I've checked my tre's so I figure I'll ad shims, what size should I get for a 4"?
It depends on the manufacturer and how much caster correction they built into the springs.

TPI sells their kits with 6 deg. shims. Some say you can get away with 2.5 or 4 deg.

The best way to find out is to take the 'Cruiser down to an alignment shop and find out how far it's off from stock.

Somebody correct me, but I think 1 deg. NEGATIVE caster is stock right? I could very well be wrong. But!!! The alignment guy should be able to look that up too.

Jody. -- with fading memory.
Cause I've a buddy who is a machinist, and can make them out of steel for nothing. Then I can play and see what shims I need, without buying a bunch. I can either have them welded to the perch, or have the perch moved and pass them on to someone esle who is in need. I did not realize NAPA has the bronze ones. Thanks!

I know some have used old spring stock (tapered), but I would still need the thick end measurements for 2.5 and 4, to have a starting point.
You should only need shims in the front if you changed your shackle length. I think it runs:
1 1/2 shackles - 2 degree shim
2 1/2 shackles - 4 degree shim
Could be wrong, also check your steering components for wear, worn parts show up more when geometry is changed. BTW shims are cheap, go buy some and you'll be sure of the correct thickness.
We're all having a really nice conversation here, cept the requested measurements have not materialized :D

Shims are cheap...steel shims are hard to find, and I do not want aluminum or bronze sandwiched between the sping pack and the axle.

Call me anal, and each to their own :cheers:
Just happened to be under the truck fixing a leaking fuel line, so I went ahead and measured mine which I believe are 2 degree shims. Thick part was about 1/4" thick by 5" long. Very hard to read the tape under there, but there's your answer.
not that it helps but most larger towns have a spring shop, which will make you any shims you wish.....and cheap AND out of metal not alum.

in Tacoma its RightWay Spring.

Seattle Benz Springs I think.
Thanks mucho!

I have bronze shims with zero issues.
For whoever it was that asked-I have 2.5 degree bronze shims from Napa on my 4" lift. Should be all you need unless you have the TPI lift. Tremendous improvement in tracking and general handling.
No offence intended, but if you have a machinist that doesn't know how to figure the dimensions for a shim, you should find a new machinist.
Thanks for the chuckle...however...

Let me put it this way. I will not waste his time, and will do all the legwork with dimensions, as he is working two jobs to keep a sick wife in medications. So you can call me the putz for looking to the LC community and the stats on line, instead of trying to figure it myself.


use trigonometry to figure out the dimensions. they are about 4.5" long so with your fancy calculator punch in tan/angle required x 4.5" to get the thickness at the end. :eek:

That's a distant memory from over 20 years ago. I was hoping to avoid bringing it back up and thought someone might have taken measurements at some point. :)

That, and memories of geometry from a drafting course for civil engineering a few decades ago will help.


I guess I will have to go there.


I'd do the math for you, I'm taking College Algebra/Trig right now...I'm not too dumb-got a 102% on my last trig test. :D
However, someone already posted the dimensions for their 2.5 degree shims, what more do you need?
Nutt'n man. I'm good to go from here.

Thanks though, and good luck in your studies!

Sure thing!
And thanks! (I need it in spanish by 10 pts my worse average-83) Anyone here bilingual? :D

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