Alignment

[ensteele]

I got my car back (Blue 94) yesterday from an alignment. The previous owner had it done twice before I bought the car. He said that he was not satisfied with either job. After picking up a screw in one of my front tires, I found that they had worn down to the belt on the inside of the tires and were worn out. I took the car in to my local dealership where they have a tech that works on SVXs. They called at the end of the day and said that the tie rods could not be broken loose. He said that it was way off and that it had not been aligned in the receint past if ever. They wanted me to authorize a couple more hours to work on it. After several hours of working on it - penatraiting oil over night, heat, and a vice and BFH, he got the job done. It was a little more expensive than normal, but at least he got it done. I have gained faith in this shop and am pleased that they did the complete job and didn't give up when they found something that was difficult.

I put on another set of stock wheels and tires that I already had, and will start saving for new 17" tires. The back ones are half worn which is too much difference for new ones on the car. All 4 new ones! Oh well!

I have 2 newer tires on the front and 2 older worn tires on the rear. Alot of people said that this wouldn't be good for the car but I've had it like this for over a year without any problems.

[CigarJohnny]

Originally posted by kvnobrien
I have 2 newer tires on the front and 2 older worn tires on the rear. Alot of people said that this wouldn't be good for the car but I've had it like this for over a year without any problems.

None that you know of at least. Don't be surprised when your transfer clutch pack goes south prematurely and your AWD no longer works.

We'll I see it this way, since the tires are always rotating at different speeds when making turns then why is it that tires that are a few mm difference make such a big deal?

[Beav]

The diffs allow different speeds at each wheel when turning, not the driveshafts. The driveshafts, front and rear, will turn at basically the same speed. Besides, the difference in circumference will not cause immediate disintegration, but will probably result in premature wear of the transfer clutch friction material.

[ensteele]

I have Toyo Proxes on the other wheels. I had the tire place check the rear tire wear and they were at 4/8 - 5/8. He also measured new tires and found that they were 10/8. That means that they are about half the tread.

My understanding is that, that is too much difference and will be bad in the long run. I think that by saving $300 now would cost me more in the long run.

[Chicane]

Originally posted by Beav
The diffs allow different speeds at each wheel when turning, not the driveshafts. The driveshafts, front and rear, will turn at basically the same speed. Besides, the difference in circumference will not cause immediate disintegration, but will probably result in premature wear of the transfer clutch friction material.

I disagree with that. More weight is on the front tires, so in all probability, they're at least 1mm lower than the back tires. Even if you have ALL new tires, and they're all at the reccamended PSI, I doubt they're exactly right on.

- Rob

[lee]

Rob,

Think about it....The belts don't shrink in circumference with changes in sidewall height.

[ensteele]

What does the tire pressure have to do with the circumference? The tire may be flat on the ground with less pressure, but that does not change the circumference or distance the tire goes each rotation.

[Earthworm]

So we know it's impossible to keep all the tires the exact same diameter unless you rotate daily. So would it be safer on the transfer clutches to have the larger diameter tires on the front or the back?

I would guess the back because if the front tires are rotating faster than the rears the TCU may interpret this as wheel spin and start trying to use the transfer clutches to compensate. I don't think the TCU can compensate if the rear tires are rotating faster than the fronts other than to give them less power at which point it's already at 10% or less.

Comments?

[Chicane]

Originally posted by ensteele93
What does the tire pressure have to do with the circumference? The tire may be flat on the ground with less pressure, but that does not change the circumference or distance the tire goes each rotation.

uh, yes it does. Think about it. A tire with a circumfrence of 100 inches will travel (duh) 100inches if rotated once. A tire with less PSI will have a smaller circumfrence than the one with 35psi and thus not travel as far.

Think about it.

- Rob

[Bwana]

Uhm...if a tire has a circumference of 100 inches...that doesnt change. The tire doesn't "blow up" and stretch like a balloon, it just squares off part of it (the part that touches the ground).

So...yeah...it's circumference would still be 100 inches no matter the pressure.

[Chicane]

You're wrong there. If a tire only has 15 lbs of air it sits LOWER, because hte part on the ground is compressed.

- Rob

[Beav]

I think y'all are trying too hard. There's too much chaos to create a hard-line value for x. You do what you can do to reduce the wear to a reasonable level, but you don't need to take it to the nth degree. By the time you get to that level the number of variables are too great.

We know that keeping the tires the same circumference, roughly, will enhance longevity. How much is academic. It's easy enough to accomplish with minimal maintenance. If tire rotations cost $50-$75, I'd be weighing the value of having them done every 5,000 miles. See: Point of No Return.

[Chicane]

Exactly my point Beav. I think it might matter if you have EXTREMELY worn out tires, and some kinda tall BRAND NEW tires... but honestly I don't think replacing 2 tires at at time is that bad of an idea, especially if you keep them the same brand.

- Rob