Unusual rear tire wear - even across, NOT inside

[twomanyprojects]

'97 318i - 25,000 miles on new tires, front tires have about 9/32 tread depth, while rear tires have worn down to between 5/32 and 6/32 tread depth, showing even wear across the tires (not worn on inside like an alignment problem.) We are very gentle on acceleration and braking, usually getting very good tire mileage (as the front ones show), and can't think what would be causing fast but even wear on the rears. Any ideas?

Thanks

Frank

[fun2drive]

Tire rotation is lacking is your main reason.
Rotate every 5K miles and you will get even wear front and back.
As long as the wear is even and you rotate on schedule you are going to get even 32's all around...

[twomanyprojects]

But why would the rear tires wear so much faster than the fronts? Not from too much acceleration in a 318i obviously, and there is more braking in the front, plus steering. It doesn't make a lot of sense that the rears would wear that fast.

[poohlikeshunny]

i always thought on e36's, the rear tires had slight negative camber...I know I do and I have e46 m3 reps...alight negative camber since I got the car...always wears a little more on the inside so I always thought I had to replace tires when they wore out because you could not rotate them?

[jijacob]

Originally Posted by poohlikeshunny

i always thought on e36's, the rear tires had slight negative camber...I know I do and I have e46 m3 reps...alight negative camber since I got the car...always wears a little more on the inside so I always thought I had to replace tires when they wore out because you could not rotate them?

Negative camber does not cause uneven tire wear. It is toe + negative camber that does this.

From what I have seen it seems like rear-wheel drive cars almost always wear the rears faster, and on top of that BMWs in particular wear the rear faster than a lot of non-sport-intended rear wheel drive cars.

Answer: stop taking the car out for late night burnouts

[twomanyprojects]

Yea right...... a 318i. He He He.

By the way, I have checked and tow-in is about even. Maybe I will just let them wear out, and try some larger diameter tires on the rear to see if I can increase the mpg (I average about 33-34 on trips, have got as high as 41 by really trying. - with an automatic tranny.)

[BMWMPow3r]

wouldn't excessive toe cause wear evenly across the tire.

[twomanyprojects]

I would think excessive toe-in would cause wear on the outside edge, toe-out (or excessive camber) would cause wear on the inside. This one is just about neutral to slightly toe-in.

[jijacob]

Originally Posted by BMWMPow3r

wouldn't excessive toe cause wear evenly across the tire.

It will wear evenly with 0 camber, however BMW's come with a slight camber. With that camber combined with the slight toe in they also come with, the inside edge wears faster.

[Auto Parts Guy]

Being RWD has a lot to do with it. Definitely rotate your tires.
and balance them. I use balancing beads in my vehicles so they balance themselves.

www.tirerack.com is the best tire site my opinion. All sorts of info & tires.. And 1 of their warehouses is like 20 miles from my house!!

[jmo69]

I use balancing beads in my vehicles so they balance themselves

I heard of these from a friend that planned on using them in his motorcycle tires. Do the really work? If they do, where can I buy some? Be better than weights if I polish the lip on my rims.

[dcwright]

Do you have a limited slip differential (LSD)? If so then your rear tires will wear faster than the fronts due to the drag in cornering.

[Crashj]

Originally Posted by Auto Parts Guy

<>I use balancing beads in my vehicles so they balance themselves.<>

The motorhome guys swear by them.

[ty20404]

I've had beads on my Jeep before, pretty cool.

As for the wear it's probably due to the toe... either that or camber or a combination of both. But if you said it's even I would assume your camber is fine and your toe is not. I had excessive toe in and wicked neg camber and my tires wore hardcore on the inside and hardly on the outside.

[Ckyo5]

Why don't you have tire charts for cars or SUV's?
We do not market to cars and SUV’s intentionally.
The main reason (among others) is due to the style of modern car tires.
For cars and SUV’s, traditional weight balancing is the best method.

[e36mikee]

the rear wheels not only have slight camber stock but also have slight toe in stock. and like said they are the driving wheels so there is a lot more force given to them even with normal driving.

[Auto Parts Guy]

I got my balancing beads from http://www.innovativebalancing.com/index.html
I swear by them. Thats my Jeep YJ in the "photos" section

They balance my swampers like no other. I had them on my last set of tires too. I've got 225/45ZR17 Pirelli tires on my bimmer and I put 4oz in each tire and they're super smooth at all speeds & tires wearing nicely at 46psi. I think they work GREAT on my car. Well worth it IMO.

[justaddwada]

AM I THE ONLY ONE WHO THINKS THE OP IS BEING RIDICULOUS?

25,000 miles and you still have 5/32? Thats a miracle from god!

[I Love My Car]

Did you check the rear trailing arm bushings? that made my brand new proxes gone in about 10000 maybe a little more. Id check those and do an alignment either way if you havent replaced them do it and be done with it.

[condorw]

Originally Posted by twomanyprojects

But why would the rear tires wear so much faster than the fronts? Not from too much acceleration in a 318i obviously, and there is more braking in the front, plus steering. It doesn't make a lot of sense that the rears would wear that fast.

it seems like normal wear (even), with possible factors like tire rotation as mentioned and type of tire. rear wheel drive will wear out rears faster than fronts just like front wheel drive will wear out the fronts faster than the rears...