Help!!! Uneven Tire Wear Problem.....

[Car Guy]

I have a 2001 Mazda Protege' with 29,000 miles and can't figure out for the life of me why the tires continue to wear unevenly.

Purchased the car brand spanking new in 01' with 9 miles on the clock. The factory tires were the Bridgestone Potneza RE92's size 195/55R15 V-rated tire. At about 10,000 miles the tires started making the 'moaning' noise similar to a tire that is not rotated, but here's the catch. I rotated them according to factory specs and had it aligned every year. At 25,000 miles (about 3 months ago) it got so bad I replaced them with BFG's Tractioin T/A's, same size and rating. The tires that came of the car had at least 6/32's left on them but it was to the point where you could bearly hear someone talking right next to you. The new tires with ONLY 3,000 miles on them are starting to do the same thing! I've been to the dealer for numerous re-balancings/alignments and it's still there and getting worse by the day! Personally I don't think this it's a tire, alignment, or balancing problem. I had talked to a person who had this same problem with a newer infinity SUV with just over 40,000 miles. He had the dealer replace almost everything and still had the same problem. The problem solver was the struts, all 4 were defective right from the factory. The problem has never come back and the truck now has 85,000 miles.

Has anyone come across something like this or has heard of someone that has. What can I do because the dealer has no clue and is no help at all! Any information would be much appreciated....

Thanks,
Car Guy

[Teknine9]

You know my friend hadthat problem and it was that his camper plates were bad. Not to sure if that will help but definatly something to take a look at.

[CapriRacer]

I was hoping that someone would reply who has some practical experience with this, but I guess I'll just reply from the theoretical point of view.

First, when the alignments were performed, was the vehicle "out of spec" and had to be adjusted? If that's the case, once irregular wear starts, it can be difficult to get rid of!

If the alignment was "in spec" how far off of nominal was it? IMHO, vehicle manufacturer's alignment tolerances are too wide. Not the nominal value, the allowable range. Modern radial tires are especially sensitive to toe in and don't like to be off the nominal value by more then 1/32" PER SIDE. (I think that's 0.06 degrees)

There is a vehicle setup parameter (basically nonadjustable) called "Ackerman" which is the amount the toe in changes when you turn the steering wheel. This is to compensate for the tire on the inside of the turn needing to turn in more than the tire on the outside. However, the amount varies with the speed of the vehicle and the radius of the turn, so there is one optimal combination of speed / turning radius. If you drive in such a way that you are far away from the optimum (outside the box), you are in essence dragging one of the tires through the turn and that causes irregular wear. Examples of what is NORMALLY driving "outside the box" are:

1) Frequent low speed turn ins when you turn the steering wheel as far as it will go, like when you pull into a parking space, especially if you only drive short distances between these - and of course the faster you 'whip in", the worse this condition is.

2) Freeway on ramp / off ramp cornering, like the 270 degrees loop arounds, especially if you drive short distances between these - and of course the faster you go, the worse the condition is.

3) Many turns compared to the miles put on. I like to use "Turns per Mile", meaning how many substantially 90 degree turns do you make divided by the miles you travel. I consider 1.0 per mile to be average. BTW, I don't count it if the road wanders a bit, only if I have to make a turn that is the equivalent of a turn at a city traffic light (However, I count freeway on / off ramps that loop 270 degrees as 3 turns.)

Also the inflation pressure has a major effect on the rate irregular wear appears.

Hope this helps.

[Car Guy]

The alignment was as perfect as possible with the new tires just because I wanted to remove that variable as a possible problem. One thing I forgot to mention is my father picked up a 02' Protégé' and had the same tires on as mine did when I got mine new. He bought it with 12,000 miles and you could tell they were never rotated because of the noticeable chopping/feathering of the tires. He replaced them Yoko's Avid 4 H-rated tire to get a little smoother ride. It did give him a smoother ride and has since put on 15,000 miles and the tires are wearing perfect with absolutely no road noise. He has rotated them on schedule according to factory specs. Does the 'H' rating have any thing to do with it? Both are cars are identical.

Thanks for the info, much appreciated! By the way, CapriRacer where did you learn all this?

Thanks,
Justin

[CapriRacer]

I don't think the H rating has anything to do with this. OE generally don't wear as well because the treadwear is sacrificed to get rolling resistance. This is more true with US cars and trucks, less so with Japanese and European.

I suspect there is another factor involved that hasn't been identified. The fact that you have another vehicle to compare to is good.

So besides the driver (and may be that's it) what else is different?

Where did I learn all this stuff? After 30+ years in the tire industry, you pick up a few things.

[Car Guy]

If it's not the driver do you have any ideas? The dealer is not helping one bit, heck, the info you gave me here is ten times what they've given me.

Thanks,
Justin