First time EVER......

kqw · 03-17-2006, 06:45 AM

I've had many, many tires on the 911 and ALWAYS the rear tires wore faster than the the fronts.

However, with the S03's guess what, the fronts have worn down faster than the rears (two years, 18K miles)....They wore even but now I am looking at replacing fronts BEFORE the rears!!!!!

Anyone else experienced this?

livi · 03-17-2006, 06:53 AM

Unusual for sure.

You certain your alignment is set up alright ?

Could your set up be creating more under steer tendency ?

kqw · 03-17-2006, 07:02 AM

Alignment seems fine and and you may be correct...

The funny thing is that the tires wore very even...Ran tire pressue at 34lbs F and 37lbs R....and since 1986, I can't remember how many sets of tires I have put on the car but, ALWAYS the rears wore out before the fronts....Weird...

Going to put another set on and have another alignment at the same time.

billroth · billroth's Garage

What size tires are they? The pressure seems high or is it just my ignorance?

Lawrence

Wil Ferch · 03-17-2006, 07:09 AM

Why are you running such ridiculously high tire pressures?.... might as well be running bicycle tires with the amount of contact patch you have.

Most "factory" labels are 29/36....and we find that for track use 32/34 works fine since after a "spirited" run we end up ( hot) 6 psi over these cold settings. If you're running approaching 37-40 lbs cold..this is going to end up way too much.

- Wil

kqw · 03-17-2006, 07:16 AM

I'm running 205-55-16's F and 225-50-16 R as I have for 20 years.

What's baffling me is that this pressue was run on Dunlop D40M2's, SP8000's, 9000's, Pirelli's etc..and the rears wore twice as fast as the fronts.

The only thing I can think of is that when I put the S03's on I also added a Brey Kraus strut tower brace...I wonder if this is causing the issue....

Wil Ferch · 03-17-2006, 07:41 AM

Well...consider this...

If you *always* wore out the rears compared to the fronts...at what point in the rear tires' remaining life did you mount these fronts...that you now say wore out first ??? Maybe that is a factor ???

- Wil

kqw · 03-17-2006, 07:48 AM

I hear ya Wil but, I put all four S03's at the same time. I've gotta believe that it's something to do with the tower brace....That's the only added factor....

Zeke · 03-17-2006, 08:42 AM

If your tires are wearing sqaure across the entire face of the tread, you can't get it any better than that, alignment, pressures or any other influnece. Expect maybe a big change in brake bias. You might just double check your rear brakes.

Yes, the pressures seem high to me, but I don't know what width wheel you run and the smaller the tire respective to the wider the rim, the higher the pressure needed to put max contact patch down.

Something doesn't seem right, but yet if the tread wear is dead even......

Wil Ferch · 03-17-2006, 10:37 AM

Zeke:

You note some pretty compelling points..... I agree that the apparent even tread wear at these high pressures is something that doesn't match well with either my experience...or with what I propose above.

Perhaps a closer look at the wear pattern will show that it * isn't * quite that even wear after-all ?? By that I mean the wear may seem that way for an "Almost gone" tire, but might not show that amount of "even" wear ...at drastically more or less miles ( with "more" or "less" remaining tread showing ) ?????

- Wil

steve911 · steve911's Garage

I'd go with the brace perhaps being A cause, since it seems to be the only differential in the set up. It could be that the brace dialed in more of something (I won't pretend to understand camber/caster/toe, etc.).

I've always had a four-wheel alignment done when I replace the tires on mine, whether its two or four tires. Like you, my experience has been that the fronts last 2x compared to the rears. If you've gotten 18K on the rear SO3's, I'd say you're still way ahead of the game. I've only gotten around 10-12K on my Kumho rears.

I run 31 or 32F and 36R -- find that it reduces the amount of pushing I get in the front end compared to running 29F/36R that the factory calls for.

Just my .02 - YMMV

ianc · 03-17-2006, 01:11 PM

If you have 18K miles and they are not worn out yet, I wouldn't necessarily say there is an issue. The strut bar is probably the cause however.

ianc

bornrich · 03-17-2006, 02:26 PM

I have SO3s on my car (81 911SC) with 205-16 and 245-16 (F/R). I don;t know how manys miles they had as my odo has been acting up. I wore out the rears before the front and I have a strut brace. I do about 3-4 DEs a year and use the car ans a daily driver. My fronts are still only about hlf worn.

kqw · 03-17-2006, 08:22 PM

Thanks folks for the ideas...

Going to put on another set all around, alignment and watch the tread wear. I'll drop the pressure to about 31 F and 36 R to see if that make a difference.

Cheers