Big, Big Time Poster
First off, have you check the alignment? Have the car been in an accident before? I would think there is very good chance, there is nothing wrong with it. If there is too much toe-in, you will wear the "outside" of the tires, you have too much negative camber, not enough toe-in.
Is your car lowered , what 540 do you have? 540ia or 6-speed. or sport? Each has its own specs. M5 and 540i sport will have even worse tire wear problem, because they are running with more negative camber than regular, none lowered 540i. Of course you can buy an adjustable alignment kit for the rear from Bavauto or BMP or some other places, but Keep in mind that BMW has specify lots of negative camber for our cars, so it will be less chance for oversteer.
With the kit in place, it is possible to have zero toe and zero camber, but your handling will suffer, however, tire wear will be better. Now try to find a place to help you put the kit in is other question. The whole trailing arm have to come off and the old bushing press out and some other stuff need to be done. That's too much work for me and can't really think the $ will be for all the work. For me, I will just have the tires flipped whne it's time and save the headach of all the work, and safe handling.
Major Contributor
I agree with Lowell - This is just the way These cars wear tires. I have seen this discussed on many forums. It part of the price of admission for these sometimes lovely sometimes challenging cars. 20k is actually pretty good for a performance tire in any book. - JT
It is a 540i/6. I'm trying to get in touch with a BMW indy mech friend and have him look at it. I understand that BMW designed the car to have + or - camber (toe in ) but from the wear on my tires I think it was excessive wear. This car is my baby and I guess I will just have to spend to get it right. I was just hoping some one knew of a cheap easy fix. Thanks for all the replys.
http://community.webshots.com/user/rzfahamay
Last edited by mike540; 12-24-2005 at 08:36 AM.
Major Contributor
Originally Posted by jaylebo
Uhh, Jay-
The outside of the tire is the outside of the tire, no matter which side it's on........think about it.
Also, I personally would not hesitate to mount a tire in the "wrong" direction in order to even out the wear. What I mean is mounting the tire so "this side out" is on the inside. YMMV, please don't try this at home, I am a professional miser.
Bret.
Major Contributor
Mike,
we still need to get our terminology straight, or you will just confuse the hell out of your tech or any alignment shop you take the car to.
Toe in or out is pretty easy, the front of the tires point in towards each other (toe in) or out away from each other (toe out)- incorrect toe setting is what can really kill a tire in a short time. Camber is how the top of the tire leans in (negative camber) when compared with the bottom of the tire.
here is negative camber- looking from the front or rear of the car: / \
here is positive camber- looking from the front or rear of the car: \ /
Here is toe, looking from above the car: / \
(toe in if the front of the car is the top of the page, toe out if the front of the car is the bottom)
As others have mentioned, BMW's have a bit of negative camber built in, but a small amount of negative camber will not usually cause excessive tire wear. It's usually worn out parts (bushings, etc) or excessive toe that really wear tires fast.
A competent alignment shop should be able to tell you which setting is off, and by how much. Then you can determine what needs to be done to correct it. If your rear tires are both wearing out prematurely on the inside edge, I would try some tires that can be flipped on the rim and then keep an eye on tire wear, and flip them (inside to outside) on the rims to maximize and even out tire wear.
Bret.
Ok from looking at what you posted i have negative camber that causing ecessive wear
Big, Big Time Poster
When this sort of thing happened on my Porsche, I took it to Sears for a diagnostic check on their Hunter alignment machine. They put it on their rack and attached the alignment tools for correct and precise readings of camber, caster, and toe-in versus factory specs for the car. They gave me the results AT NO COST, but would have done the proper adjustments for ~$90. Given the free diagnosis and relatively modest cost, plus warranty on their work, this may be a good place for you to start.
FWIW, I've used a spool of thread and toothpicks to set toe-in, and a spirit level and toothpicks to set camber, and this method gets results as accurate as laser aligment machines. Using this technique while parked on a level and flat garage floor, the car will then track straight ahead, hands off, at 100 mph.
Major Contributor
Eccentric bushings are your friend.
-Trevor Ely
'88 535is
'95 M Sport 540i (1 of 200)
'91 M5
4 Grand Master
Yes these are definately a good idea with larger (and wider) rims exacerbating things. I'm interested in a camber adjusting kit, at 150k+ surely all rear bushes are pretty much DEAD anyway, so it cannot be a bad idea. Changing the wheel size and/or lowering the car and not adjusting the very neatly set (slightly) negative camber of the factory settings (that is now somewhat out) seems plain silly to me. I'll be doing it soon.
Either that and/or trying to find a tyre that is non-directional. My wheels are not enormous, but I like the idea of having the rear geometry right and not having too greatly a reduced tyre life.
I have 225/45x16s, does anyone know if non-directional versions are available? All mine say 'Rotation>' and it is always a royal PIA at the tyre shop. I am sure the performance/weight savings of directinal tyres is worth sacrificing. I can see why all the tyre companies are so keen on them tho
(535i now with a complete 540i/6 M-tech suspension, results soon to be posted about)Nick
Join the Aussie 540i LE yahoo forum
08/88 535i e34 M30+miller MAF, 'stiens, tints & teeth!
Big Time Poster
I can back that up with my story of lowering an 81 528i (e12 car) Because of the rear trailing arm geometry, lowering causes rear toe out as well as negative camber. And toe out wears the inside edge of the tire. Since the front runs toe in, it tends to wear the outside edge and rotating tires helps to even things up. But the inside of my rears still wore much faster than the outside of the fronts. I finally did a combination of offset trailing arm bushings and a little elongation of the inboard bolt holes to get the rear toe back where it belongs, and the tire wear is just fine--even with all that negative camber still in there.
Now for the e34 cars--the rear suspension has a little toe correction link, commonly known as a dogbone, that should keep the rear wheel toe where it needs to be during suspension travel. Dogbones wear out, so your toe gets out of spec and chews up tires. If your car is lowered, I suppose that would preload the dogbone and wear it out faster. Get the whole car alignment checked, as recommended earlier, and if the rear toe is out of spec, check those dogbones.
Lots of luck with it
Karl
Posting Permissions
Reply With Quote
