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View Full Version : Front Tires wearing on the inside??


Evrgrnmtnman
03-18-2008, 08:17 PM
Curious what would be causing the inside of my front tires(35") to wear???
Alignment, Tire Pressure????
If alignment, where's the best place to go?

wesintl
03-18-2008, 08:55 PM
too much toe in... adjust you tie rod a couple turns out.

Evrgrnmtnman
03-18-2008, 10:50 PM
too much toe in... adjust you tie rod a couple turns out.
Never thought of that! I'll give that a try.....thanks!

SteveH
03-19-2008, 12:24 PM
I believe too much toe-in (front of tires closer together than the rear) would cause the outer edges to wear. You can measure your toe carefully with a tape measure or measuring stick - Google this topic and you'll see sites telling you how.

Camber rarely changes in 'cruisers (unless something is bent, or you shimmed the knuckles oddly), but the camber, caster, and toe (together) create the full alignment picture.

I don't know of good shops in Denver, but don't go to a chain joint (if you can help it). Find a Mom-and-Pop place with a good reputation and solid-axle experience.

Steve

Evrgrnmtnman
03-19-2008, 12:50 PM
FYI- 93 Pickup with SAS....Yea, like to find someone that knows what their doing....

nakman
03-19-2008, 12:58 PM
It'll take you 10 minutes to measure your toe in: Put the front axle up on jack stands, tires on, about 1/2" off the ground. Wrap a strip of duct tape around each tire tread. Spin the tire, then use a sharpie to mark a single skinny line all the way around your tire. Then measure your distance in front, compare to distance in rear... IIRC you're shooting for about 1/4" closer in front than in back.

Evrgrnmtnman
03-19-2008, 04:41 PM
It'll take you 10 minutes to measure your toe in: Put the front axle up on jack stands, tires on, about 1/2" off the ground. Wrap a strip of duct tape around each tire tread. Spin the tire, then use a sharpie to mark a single skinny line all the way around your tire. Then measure your distance in front, compare to distance in rear... IIRC you're shooting for about 1/4" closer in front than in back.
Thanks! But what do you mean by 1/4" closer in front? Shouldn't they be the same distance apart. How do you keep the Sharpie steady on the tire as it's spinning? Seems your hand would move a bit...........

SteveH
03-20-2008, 09:55 AM
You wnat a little toe-in to keep your tires fighting each other a little bit - this prevents shimmy and wander. More than 1/4" gives you too much tire wear. Also, when you drive down the highway, the dynamic forces on your tires pull them back a bit, so you see less than 1/4" of measured toe when actually driving at speed.

Some folks find a molded rib on the tire (one that is true around the tire) and use that as a measurement reference point. Depending on the tread pattern, you can hold a screwdriver against the tire and scribe a line in the tire (leaving a dark scratch mark). A sharpie would work on a clean tire, too - the duct tape is a novel approach, too, and gives you a smoother writing surface.

I think Harbor Freight and JC Whitney sell an 'alignment gauge' for $10 or so that does this - it's a glorified tape measure.

With a SAS, you might want a shop to check caster and camber, since you have a custom setup and may have significant changes from stock. I'd think you'd want to use a solid axle minitruck's alignment specs for your swapped truck.

Steve

nakman
03-20-2008, 11:19 AM
If you have a 1/2" copper coupler laying around in your plumbing box (or anything similar), you could use that as a sleeve to help keep the sharpie in line side to side. Otherwise just put your finger under the sharpie, then use your other hand to drive it into your duct tape. Kind of like a miniature pool cue? The motion is allow the pen to go "in and out" with your tire, without allowing it to go side to side. there's always more tape, if you need to practice.

leiniesred
03-20-2008, 12:47 PM
Rest the sharpie on a jackstand. There is usually a nice groove for a pen on the top of the cast ones.

I agree. I bet you are towed out too much.

Me? I have a stick that is a little shorter than the width between my front rims. I put a deck screw in the end of the stick to make the length of the stick adjustable. Adjust screw to match width between rims in FRONT of the axle. Move behind the axle to measure the width between the rims on the BACK. Back should be about 1/16th wider than the front adjusted stick. Adjust tie-rod on truck if required. Roll truck out of and back into the garage. re-test.

We're talking about a TRUCK here, not the space shuttle.

I've tried other ways too. Like "stringing" the car NASCAR style. I was more accurate with the adjustable stick on the inside of the rims. My rims are pretty straight. I guess if you had wobbly, bent, deformed rims it wouldn't work unless you rolled the truck forward so you can measure in the same places with the stick behind the axle.

Caster and camber are tough to change on a solid axle. Adjust camber with a torch on the housing. Heat up the top or bottom of the tube, let it cool, repeat. You'll shrink the tube on either the top or the bottom to "adjust" the camber. On my Dad's solid rear axle mustang, this is how you "bend" the housing to get static negative camber on a solid axle. Tough on bearings and axleshafts? Sure but who cares?

Setting caster on the SAS is done by changing the length of the shackles. But there are limits to how long/short you can make those. Raise or lower the front leaf spring mount. Not easy. You can shim the spring perches or rotate the perches. All these are great, but it messes up your pinion angle! the only option that doesn't mess up your pinion angle is to cut the kunckles and rotate them.

Basically, no one adjusts caster/camber on these rigs.


I've also done the duct tape line, (actually, I just chalked the tire) but that involves jacking up the truck. Extra work for me!

TIP : Push a tack into a block of the tread to hold the far end of the tape measure since you'll probably be working alone after all, that is why they put that hole in the end of your tape!

On the racecars, we simply used "toe plates" just two flat rectangles of steel. Lean them against the tire with the tops touching the front and back of the tire around the centerline of the wheel. The distance the bottom of the plates are from the tires doesn't matter. Just lean them up there. Measure on the bottom of the toe plates on the ground. Race tires are pretty well built and uniform so it is actually pretty accurate. Being able to slide the tape under a very low car and hook the edge of the plate made it easy and fast to check total toe even when working alone.

After awhile, you'll be able to SEE correct toe just with your eyeballs.

My Dad simply uses toe plates on his Mustang racecar too.
(but let's face it the 1970 Mustang chassis is so "loose" that precise chassis setup isn't really going to buy you much!) "hang it out!"

nakman
03-20-2008, 01:12 PM
Stephen, that stick & screw method is genious.. I'm going to do that one next time. I'm often amazed at the stuff you know... and here I was thinking I wouldn't learn something today. :)

Evrgrnmtnman
03-20-2008, 05:45 PM
Some great ideas people! I'll give it shot this weekend and hope that I don't screw anything up..........

Uncle Ben
03-20-2008, 06:06 PM
I've always used two long straight edges. Bungie cord them to the outside of the wheel parallel to the ground. They need to be longer than the diameter of the tire! Measure the distance between the rear and the front lines and adjust accordingly. At this distance of separation you want about 1/8" difference.

leiniesred
03-21-2008, 10:07 AM
Uncle Ben's bungee corded straight edges on the tires do the same thing as the toe plates (as long as you don't have bodywork in the way.)

Evrgrnmtnman
03-21-2008, 10:33 AM
When your talking about separation and distance. I'm assuming your meaning the distance apart from the front of the tires, from the distance between the back of tires?

nakman
03-21-2008, 10:53 AM
When your talking about separation and distance. I'm assuming your meaning the distance apart from the front of the tires, from the distance between the back of tires?

A-B= 1/4" or so..

Evrgrnmtnman
03-21-2008, 02:20 PM
Why not just measure from the same spot inside the front of the tire, and do the back side at the same location?

Uncle Ben
03-21-2008, 02:52 PM
Why not just measure from the same spot inside the front of the tire, and do the back side at the same location?


Radial tires often have wavy sidewalls so the best thing is off the bead seat of the rim (great tool Rude Boy!) of make sure you have a good average cross section (thus the straight edge).

beatdown83fj60
03-28-2008, 01:17 AM
Some great ideas people! I'll give it shot this weekend and hope that I don't screw anything up..........

If you don't get it figured out I know that Evergreen Automotive in Evergreen (duh) has a nice alignment rack and they work on more than the average vehicle. 303-674-0214. They will definitely be able to figure out a crossover setup ;) .

78landcruiser
03-28-2008, 08:33 AM
Here's how I drew my lines:

http://www.youtube.com/watch?v=zjoXHN2-PRM

Not perfectly accurate, but fairly so, and I was happy with the outcome.

Read more about my 78 FJ40 rebuild here:

http://78landcruiser.blogspot.com/

Evrgrnmtnman
03-28-2008, 09:00 AM
Ended up taken it to Lakewood Alignment on Allison St.......$75.00, but figured the cost of tires was worth it.......

SteveH
03-28-2008, 01:44 PM
What did the shop conclude - was it way out of whack? Were camber/caster ok?

Evrgrnmtnman
03-28-2008, 08:54 PM
The total toe was -0.98 degrees when I brougth it in(Specified Range -0.01 to 0.39 degrees). They were able to set it at 0.23 degrees. So, yes it was way out of wack causing the inside of the tires to wear. Cross Camber and Caster were within specs!