Rear wheel balance (toe in angle)

[mike540]

About a month ago one of my rear tires failed on my 95 540. When I removed the wheel I noticed my tires were coned < on the inside. I just brought my car to have a wheel balance and was told by the mechanic that there are no adjustments to balance out the rear wheels, but he could tell that the rear whell needed a balance.

My car is a 95 540 with 165,000 miles riding on 18in BBS wheels. I have had this car for the last 65,000 miles. This is the 3rd set of tires, and I never had this problem before. Is there a known problem that goes wrong on E34's, is my suspension shot? should I just bring it to a BMW shop and get raped on the price to get it fixed?

[Rigmaster]

Hmm. Sounds like we need to get your terminology straight. You mentioned "balance" a couple of times, with a couple of different meanings (I think).

Balancing a wheel/tire is just to make it ride smooth, and (hopefully) allow the tire to wear evenly. It cannot cure a bent wheel or damaged or misaligned suspension.

Your mechanic is correct that there is no adjustment that can be made for the rear wheel ALIGNMENT. Alignment is done by making sure the wheels/tires are not leaning in too much (camber) or pointing in or out too much (toe in or out) using adjustments in the suspension pieces (if available). Most BMW's have no provision for alignment on the rear, and only toe adjustment on the front- without replacing pieces (offset bushings or upper strut bearings, etc).

If you can clarify what exactly the mechanic told you- we can better try to help you.

EDIT- after re-reading the subject line- it looks like the TOE is out of whack in the rear. The only adjustment can be done by installing adjustable trailing arm bushings and having it set by an alignment shop.


Bret

[jjw]

Right, there is no adjustment provided for the rear. I have the same type of tire wear on mine. Although mine is lowered and runs on 18" tires. One way is to check tire wear more oftern and have the tire flipped inside out once a while, it may cost some $ for tire shop to do it, but still better than buy new tires when half of the tire still good.

[Jay 535i]

Right, there is no adjustment provided for the rear. I have the same type of tire wear on mine. Although mine is lowered and runs on 18" tires. One way is to check tire wear more oftern and have the tire flipped inside out once a while, it may cost some $ for tire shop to do it, but still better than buy new tires when half of the tire still good.

Huh? If the tire's non-directional, why not just rotate it rather than flip it on the rim?

If it is directional, then flipping it won't help cuz you'll have to mount it on the other side of the car and you'll have the same problem -- just in mirror image.

[jjw]

For me, rotate them doesn't help, since they all wear on the inside. As for none directional, you can just flip on hte same wheel and on the same side. But for directional, you have to flip and change to other side, so inside of left tire will become the outside of right tire. Only tire won't work is Asimetrico tires.

[mikell]

Have you checked your "dogbones"?

[Jay 535i]

But for directional, you have to flip and change to other side, so inside of left tire will become the outside of right tire.

No. If you flip and rotate, the outside of the right tire will become the outside of the left tire. So that won't solve your uneven wear problem if it's due to excessive camber.

[jjw]

Trust me, it work. I have been doing this for the last two sets of my tires. Just try to see, maybe draw a picture will help.
If you just flip the tires, will it be inside become outside? But for the directional tires, you can't put the same tire at the same spot, because rotational directions, backward. So you put it on the otherside of the car, and it will be the right direction rotation and inside become outside.

[mike540]

Yes the toe in angle is off. The rear wheels are angled in. I am getting more wear on the insides of the tires. I have been through 2 set of tires and never realised the wear before.

I thought the M5 (or 540msport) ran 18 in wheels. So I figured there has to be somthing to correct my problem. the wear would be like this > <

[Kalevera]

I don't know if I'm understanding this correctly, but..I mean, to be frank, with no rotation and (IMHO, too large) 18" wheels, 20k+ miles for one set of tires is very good.

The suspension has negative camber in it from the factory, and throwing larger wheels and low pro tires on it exacerbates things. Fronts wear on the outside, rears wear on the inside.

The car may have worn trailing arm bushings (where they meet the subframe), but an alignment would more than likely show one side with significantly more toe than the other. You could have two bent trailing arms...always a possibility if the car has been in an accident or has gone over stumps/hit curbs/the like. The car could have an extremely dead set of rear shocks, two broken rear springs, or blown out shock mounts that would cause the rear end to drop a few inches and put more weight on the inner edges of the wheels; but you'd know about it when driving the car. All of these situations are unlikely, though...I think it's just another negative aspect of running 18s.

EDIT: as previously mentioned, checking the dogbones is a good idea.

best, whit

[jjw]

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.

[Johntee540]

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

[mike540]

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

[Rigmaster]

No. If you flip and rotate, the outside of the right tire will become the outside of the left tire. So that won't solve your uneven wear problem if it's due to excessive camber.


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.

[Rigmaster]

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


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.

[mike540]

Ok from looking at what you posted i have negative camber that causing ecessive wear

[Dash01]

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.

[MTechnik540i]

About a month ago one of my rear tires failed on my 95 540. When I removed the wheel I noticed my tires were coned < on the inside. I just brought my car to have a wheel balance and was told by the mechanic that there are no adjustments to balance out the rear wheels, but he could tell that the rear whell needed a balance.

My car is a 95 540 with 165,000 miles riding on 18in BBS wheels. I have had this car for the last 65,000 miles. This is the 3rd set of tires, and I never had this problem before. Is there a known problem that goes wrong on E34's, is my suspension shot? should I just bring it to a BMW shop and get raped on the price to get it fixed?


Eccentric bushings are your friend.

[genphreak]

Eccentric bushings are your friend.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

[Karl]

Mike,

...
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.

...

Bret.
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

[632 Regal]

your car dont look too low in the rear, have him check the dogbones and bushings and arms. this is very common on our cars especially with bigger wheels.

just like everyone is saying.