Solid axle camber wearing out tires

[Dorsey]

I have a tubular axle on my '29 and it's wearing out tires at the outer edges after 5,000 miles or so. I've confirmed that the camber is within the 1/2 to 1 1/2 degrees range for bias ply tires. Speedway Motors told me that all of their tubular axles are built to those specs, so replacement doesn't seem like an option. Caster is 6 degrees and toe-in is 1/8 inch.

The literature and at least one teaching mechanic confirmed that that camber spec is for bias-ply tires, while 0 degrees camber is recommended for radials. I know that people run tubular axles with radials and my question is: how do they / you do it? Is it a magical combination of wheel diameter and width and tire size? Or, do you have the axle bent to get the correct camber?

After 20 seasons on the road, I've decided to garage the car until I sort this out. It needs yet another set of front tires and I'm tired of paying for tires that only last two or three seasons. If the right answer is to replace all four tires with bias-ply, I'll go that route, but I'd like to be as sure as I can that it will solve the problem.

Thanks, everyone.

[dlotraf33]

Is your ackerman off? When wheels are turned sharp the outer tire should not be turned as sharply as the inside tire. I had this problem on a 66 pu when spindles were changed to disc. brakes. It would wear the outside edges of the tires more than the rest. With a solid axle vehicle an imaginary line should go from center of kingpin thru center of steering arm ( where tie rod ends connect ) and intersect at the center of rear end. If incorrect differnt lenth steering arms or bending of arms (typically out toward tire) would be required.

[HWORRELL]

dlotraf33 has a valid post and heres a good article on it.
NTBA

Unless extreme, camber is not a tire wear issue. Toe is usually the biggest tire wear culprit.

[jerry clayton]

are you using spindles that have been reversed ???front steer vs rear steer???one the steering arms need to be close to tire (front) the other away from tire(rear)

Also maybe rotating /reversing your tires will get you more tread life--


typeing at same time but slower!!!!!!

nice artical, explains with drawings what I was trying to say---

[cffisher]

Jerry that was my thought but he'd have to dismount them then remount but still cheaper than new tires.

[rspears]

Jerry that was my thought but he'd have to dismount them then remount but still cheaper than new tires.

Why do you say that, Charlie? I recall long ago people saying that you cannot change the rotation direction on a radial (move a DS tire to PS), but I think that was proven wrong years back, or else I'm in a dream world. My tire shop does the backs to fronts, fronts crossed to backs at every rotation. And on my Jeep with the big meats we throw in the spare going to RR, LF going to spare to further confuse things.

[jerry clayton]

Roger--not to answer for Charlie but---car probably has bigs/littles so tires don't rotate to rear--got to reverse tire on wheel to change the wear outside to inside.

[dlotraf33]

Why do you say that, Charlie? I recall long ago people saying that you cannot change the rotation direction on a radial (move a DS tire to PS), but I think that was proven wrong years back, or else I'm in a dream world. My tire shop does the backs to fronts, fronts crossed to backs at every rotation. And on my Jeep with the big meats we throw in the spare going to RR, LF going to spare to further confuse things.

You wouldn't reverse rotation. You move left front across to right front. Out side wall is now inside, same roatation. Thats why you have to unmount and remount. It might be hard to visualize but if you think about just sliding the tire straight across from one rim to the other.............

[dlotraf33]

and to add to the to the toe, too much toe in will wear outsides, too much toe out will wear insides out faster.

[Dorsey]

The Ackerman was correct when I located the front and rear axles a few years ago following some rear suspension work, but I'll confirm that. The steering is a side-mounted Mustang box connected via drag link to normally-mounted spindles. I did find that the toe had drifted out (by a lot) two summers ago - so bad that it caused shimmy. That could have caused the wear problem, but that doesn't explain wear on the first few sets of tires when I know that the toe was correct. Of course, I'm only "really sure" that the toe was correct back then, but maybe not.

From your replies, it sounds like the problem is toe and not camber. The guy at Speedway also suggested toe-in, but I wanted to hear from the folks here.

[The Bat]

Just 2 more cents wroth,PSI too low also can ware tire outer tread,also a tire that is too wide,plus rims that are too wide and or wrong off set

[Dorsey]

I maintain the pressure at 32psi, but what is the "right" offset? At the front I have 15" rims, 5" wide, with 3.5" backspace using 195-70 R15 tires. Those were the narrowest and tallest tires I could find at the time.

[rspears]

Roger--not to answer for Charlie but---car probably has bigs/littles so tires don't rotate to rear--got to reverse tire on wheel to change the wear outside to inside.

OK, I see what you mean. I was thinking of one side wearing, not both evenly. Makes perfect sense to dismount/remount. Sorry I was being dense. You were waaaay ahead of me, Charlie!!