axle shims

[Jbm1956]

Has anyone used the pinion angle shims from speedway motors before for there 55-59 dropped axle. My local napa wants $100 for shims they only sell them by the box of 6 which makes no sense lol. Im not to familiar with shims if they need to be a certain dimension or if these will work. There 2 1/2 inches wide and 4 degree for $20.00 thanks guys

[Jbm1956]

http://www.speedwaymotors.com/Leaf-S...hims,3354.html

[dwcsr]

use something lie this , they are solid not open in the center

http://www.summitracing.com/search/p...on-angle-shims

[Jbm1956]

Ok so the ones at my local 4 wheel parts will work. Just make sure there solid instead of open.

[dwcsr]

yes

[Jbm1956]

Are these shims required ive heard different opinions from different people. Do I even need to run shims

[vidman]

Use them if you need a pinion correction..

[Jbm1956]

Does running a 3 inch drop axle and 3 inch drop springs require a pinion correction. Thanks

[vidman]

You have to check it with a angle gauge. If your trans yoke is pointing down at lets say 3 degrees then your pinion must be pointing up at the same amount. The two angles must be as close to the same angle as possible. If they are the same they will cancel each other out so you end up with no vibrations in the drive line. sounds kinda high tech but if you keep both u-joints the same angle you will be OK..

[MARTINSR]

Originally Posted by Jbm1956

Does running a 3 inch drop axle and 3 inch drop springs require a pinion correction. Thanks

There is no pinion on the front axle. What that is referring to is the rear axle.



On the front axle what it is for is to correct "caster".







The more caster the less rolling resistance and the more high speed stability you have.

When you just bolt the axle on and lower the front more than the rear your axle ends up leaning forward loosing caster. So adding the shims brings the caster to where it needs to be.

To give you an idea about caster, your truck would typically have 2-3 degrees positive caster. Stock it was probably 1 at the most. And on the other end is a Bonniville land speed record cars will have something like 18 degrees positive caster!

A BMW 3 series will have something like 4 degrees while a 7 series designed for high speed Autobahn driving it runs up to 7 degrees.

The less caster the more the tires "bite" around tight corners while the higher degree is for high speed straight line driving.

Brian

[Jbm1956]

Well that just confused me even more lol. I know dubie used shims on his straight axle but im not sure who else. But I heard from another member on here he ran his with no shims with the same drop with no issues and it aligned properly. I appreciate the help guys keep it coming

[Jbm1956]

So would the best way be bolt it up without shims and take it down to the alignment shop and see if it needs shims or not?

[MARTINSR]

I never said you HAVE TO use shims, not by a long shot. Sorry if it sounds that way. All I am saying is that IF you do need to change the caster, shims is how you do it.

Brian

[Jbm1956]

Yea I got you. I guess I just need to bolt it up and take it down and see if I need shims instead of me eye balling it. Cuz the rear is just as low with the flip kit. So I might be fine

[MARTINSR]

Originally Posted by Jbm1956

So would the best way be bolt it up without shims and take it down to the alignment shop and see if it needs shims or not?

Maybe, the "alignment shop" scares me. If it's your typical tire place they don't have an F-ing clue about anything their computer doesn't tell them.

Basically, drive it, if you have having any problems like it's wandering, you quite possibly need more caster.

Brian

[dwcsr]

Originally Posted by Jbm1956

Well that just confused me even more lol. I know dubie used shims on his straight axle but im not sure who else. But I heard from another member on here he ran his with no shims with the same drop with no issues and it aligned properly. I appreciate the help guys keep it coming

These shims are used on to change pinion angle and/or caster angle. On the front they are for caster adjustments and on the rear for pinon angle. You may not need to change pinion angle just because you have a drop axle, but you probably need to do something with the caster angle because it is a drop axle. Shims are an alignment device sometimes not needed at all. So have your shop do an alignment and see. If you get a drive line vibration check the pinion angle.

[nvrdone]

Ok now I'm confused. Are we talking changing the rear axle pinion angle or the front axle caster after installing a dropped axle?
If we are talking changing the front caster, my stock axle had a 3deg shim. When I installed my 3" dropped axle I added an additional 3" deg shim and now have 7 deg caster. I know it doesn't add up but that's what it is. The truck tracks great at any speed. There is a trick to adding the additional shim. I will share later if you want the info

[Jbm1956]

Yea please do. Ill take all the info I can. I appreciate the help from everyone. Such a great forum.

[nvrdone]

Ok, I'm guessing you have / had a stock beam axle in the front. The stock shims sit between the spring pack and the axle, with the head of spring center pin going thru the shim and into the axle. This keeps the axle centered on the spring. Now if you add an additional shim below the original one, the pin head isn't long enough to go into the axle.
I got 2 new shims, welded the center hole & re drilled them so the center pin would fit thru. Then replaced the center pin with a new, longer one. The new shim is now installed as part of the spring pack, with the original shim mounted as it was.
Basically, the new shim is installed like a spring leaf.
Hope this is clean and you can follow the process.

[dubie]

I used a 6 degree caster shim to correct my caster once we dropped the truck 6 inches. It's necessary in order for your steering wheel to return to center once you have turned a corner.
They should look like this once installed

[agnes the dog]

Originally Posted by nvrdone

Ok, I'm guessing you have / had a stock beam axle in the front. The stock shims sit between the spring pack and the axle, with the head of spring center pin going thru the shim and into the axle. This keeps the axle centered on the spring. Now if you add an additional shim below the original one, the pin head isn't long enough to go into the axle.
I got 2 new shims, welded the center hole & re drilled them so the center pin would fit thru. Then replaced the center pin with a new, longer one. The new shim is now installed as part of the spring pack, with the original shim mounted as it was.
Basically, the new shim is installed like a spring leaf.
Hope this is clean and you can follow the process.

I had the same problem with the center pin being too short to act as the locating pin on the axle. I like your idea. I used a different approach which worked well too. I ground a grade 8 nut to match the diameter and shape of the original center bolt. I then bored the threads out and used it as a spacer, reassembling the spring pack with the spacer between the springs and head of the center pin. Worked perfectly and took about 10 minutes. Sorry, I don't have any pics of it.

[76er]

Does all this still apply if your using dropped springs instead of a dropped axle?

[MARTINSR]

It depends how the axle is "dropped". If it has a reverse eye at the back then you are raising the back of the spring more than the front so it would effect caster. If it is simply a de-arched spring than realistically I don't believe you need it. But it's a combination of a lot of stuff, the front of the truck coming down also makes a difference, the front of the spring is being lowered more than the back, thus you are loosing caster because it's tilting the axle forward.

Brian