Front tire excessive wear
 

Man, my Fordor blows through front tires crazy fast. I've tried he following: I straightened the axle to remove a bow (someone must have towed it from the center of he axle in he past). While off, I checked the alignment and angles of the kingpin and spring perch holes, and they were fine. I've check and reset the toe-in to spec a number of times. I've tightened the tie rod and drag link ends to remove play. I've adjusted the 2 tooth steering box and there's very little play in the wheel. I've got new hubs and wheel bearings, with the pre-load set correctly. The kingpin bushings have no play. The tires are balanced. The radius rod ball is not worn and it's in the original type steel socket. The shocks have good resistance moving up and down. The spring is not sagging- there is good clearance between the spring eyes and the axle. The shackles and bushings are new. These are Firestone 19" whitewalls that are kept at 35 psi religiously. The wear pattern is even right across all the treads. They are not feathered or scalloped. They can't have more than 4,000 miles or so on them and they are close to having to be replaced. The rear tires look brand new almost! Any suggestions?

Re: Front tire excessive wear
 

I can't answer why your front tires are wearing faster than you expect but have ypu ever considered rotating you tires to get longer life out of the set?

Re: Front tire excessive wear
 

Don’t rotate your tires until you locate your problem. No sense wrecking 4 tires.

Re: Front tire excessive wear
 

Bought a set of Firestones several years ago at a swap meet. New in wrapper, but no
DOT numbers. Keep in dark dry environment till I got coupe on the road. Front tires were nearly slick after 2000 miles. Went with Coker radials. I think the Firestones may have been knockoffs. My vehicle is in great shape also. I am perplexed at the wear. Hope these radials are better, the ride sure is.

Re: Front tire excessive wear
 

On the first set of 4 tires I had, I rotated them and burned through all 4 after only a few thousand miles. It's cheaper to replace 2 tires at a time than all 4.


I wonder if the trunk I have hanging off the rear, full of heavy spare parts and tools, is somehow throwing off the weight bias. This would take some weight off the front axle and shift it to the rear, and I would suspect that would cause the rears to wear faster. I'm perplexed.

Re: Front tire excessive wear
 

Now I'm confused. It took 4000 to wear out just the front but just "only a few thousand miles" to rear out all four when you rotated them? I'm done.

Re: Front tire excessive wear
 

Need more information. Are the tires wearing more on the inside or outside.
If you move your fingers from the inside of the tire to the outside does one
way feel smooth and the other rough? Here is a like to Marco's site on
adjusting toe. https://web.archive.org/web/20140824...shop/align.htm

Re: Front tire excessive wear
 

I would check your Ackermann geometry. This could be causing wear during your turns. Jason

Re: Front tire excessive wear
 

? Time for a trip to an alignment shop ? Sound like you have covered all of the bases!

Re: Front tire excessive wear
 

Check distance from front axle to rear on each side. If the front axle is not parallel to rear this could cause wear. Some alignment is off to cause this.

John

Re: Front tire excessive wear
 

Hello Will N,
Looks like you covered every thing, page 283 in the service bulletins may have the answer, it explains why the steering arm angles were changed, I had the right tire only scuffing out regardless of the toe in set correctly, the left side was either bent or an early arm in its place, there was 1" of space between the tie rod end and back plate, the other side was about a 1/4".

I have always wondered if the vendors that re-ball these parts ever check them, someone ending up with worn tires.

Re: Front tire excessive wear
 

Have someone follow you down the road to see if your car is tracking straight,
or at a crab angle. If crabbing, you probably have a broken center bolt in either the front or rear spring, or the axle you straightened is not true, all of which
cause tire wear.

John

Re: Front tire excessive wear
 

You mention all the things you have checked. Are you aware that the front crossmember establishes the 5 degree tip back of the king pins. Unless you or an alignment shop puts the magnetic gauges on the spindles you may not have correct caster. The individual who recommended you visit an alignment shop should be your next step. Let THEM check your caster angle, camber angle, king pin inclination, toe in, toe out on turns, and spring height. You don't mention your length of ownership on this car or if any previous tires gave you better service in the past.

Re: Front tire excessive wear
 

Thanks guys for your suggestions. Brian T, I looked at the space between my backing plates and the tie rod ends, and it is equal on both sides. Jayvee34, I've been taking some measurements to see if I'm out of square. I used a framing square against the rear axle housing and front axle at the same spot on both right and left to draw a line on my garage floor, and I measured. The distance between the front and rear axles right and left is the same down to the 1/16". Then using the framing square against the leading edge of the hubcap I marked lines on the floor front and back, left and right. I made sure that the pitman arm was pointing straight down using the square too. The left side measured 7/16" longer than the right. I know that these measurements can be influenced by the steering being even a little off center, but if the pitman arm is perfectly vertical, shouldn't that mean that the steering is centered? If so, then with my steering centered, it seems my front tires are pointing off to the right somewhat which would create the longer wheelbase on the left side. My toe in is set correctly, so I guess that while I'm driving straight ahead my steering is actually a little to the left of center to keep both wheels pointing straight ahead. But would this contribute to the uneven wear? KR500, is it just the cross member that sets the camber, or is it the relationship between the cross member and the wishbone ball joint. What kind of alignment shop would be versed in a solid axle front suspension? A truck shop?

Re: Front tire excessive wear
 

Front crossmember establishes caster, which is the tip back at the top of the king pin leaning towards the rear much as a bicycle frame has fork leaning back. This is what causes the front end to want to move in a straight forward direction. Camber which is the spindles leaning in at bottom to place the weight of the car on the larger inner wheel bearing and king pin inclination is the inherent spindle and king pin positions to allow a line drawn thru the king pin to intersect the bottom center of the tire to the road so the tire pivots on a small point on the road rather than scuffing as the spindle spins the tire

Re: Front tire excessive wear
 

I will add some photos from the Ford alignment school booklet

Re: Front tire excessive wear
 

Thanks, does anyone know what the caster angle, camber angle, king pin inclination, toe out on turns, and spring height specifications are for a Model A?

Re: Front tire excessive wear
 

Caster max. 6 1/2º min. 3 1/2º Camber max. 2º min. 1/4º Camber plus side inclination max. 9º min. 8 1/4º Toe-in 3/32 Toe-out 15º turn 17, 20º turn 23 3/4 Tolerance 1/2º
These specs are for the Model A from the 1936 Ford Service Bulletins.

Re: Front tire excessive wear
 

Thanks! Now to find an alignment shop that can work on solid axle front ends.

Re: Front tire excessive wear
 

Unless the shop has to bend the axle to bring in caster angle or camber angle most shops can at least check what your angles are. They generally attach a magnetic gauge to front spindle while the car is on a rack resting on what are referred to as Ouji boards. The tire is turned 20 degrees in one direction and then 20 degrees in opposite directions and the magnetic gauge will give them caster angle, camber angle, and king pin inclination. A different gauge is used for checking toe in.