Cause of alignment change.

[Hoyt Clagwell]

A couplethree years ago, I did my own front end toe alignment using string.* Afterwards, the car tracked perfectly and there was no excessive wear issues. There was a slight amount of extra wear on the innermost inch of each tire but not enough to effect their useful life. That is, when they got down to the wear indicators, the innermost edge of each tire was nearly bald but that didn't affect in any way, the total service life.

Since then, I have replaced the original style 18s (7X16 ET46) with style 68s (7.5X16 ET41) Since my original alignment was working very well for me, I neglected to take a really good look at the wear on the new tires. (used tires came with the rims) I assumed everything would be fine and I only looked at the tread that was easily visible from a walk around. By that standard, I had plenty of tread left for another season of driving.

While under the car working on my transmission, I noticed to my horror that the innermost inch of each front tire was worn pretty much to the chords! The wear was not tapered or feathered across the whole tire, just at the innermost inch. I assume this means that I now have way too much toe in.

Can changing rims/offset cause this alignment issue?

(I originally set the toe-in so that the front edge of the rim was 2mm in from the rear edge of the rim)

*Here's a great video from FCPEuro on how to do your own alignment using string. This is pretty much what I did to get the great results I had with the original wheels.

[zellamay]

First of course, is to re-measure it now. You don't mention camber at all. What is it now? I don't think that rim difference would matter much. Are the tire sizes the same?

[rf900rkw]

Wheels and tires will not change the alignment as long as there is no play in the suspension. Another point is cars will track "perfectly fine" with a fair amount of toe, in or out. You need to have a fairly extreme misalignment before the car will get nervous in a straight line. And toe will not ever cause a pull, no matter how many times you read that in the interwebs.

Measure it. Then roll the car out and back in, and measure it again. I have never found the string-on-stands method to be accurate.

[pine1000]

I've done the string method before, but on these cars (since the rear is not adjustable) it is far easier to use toe plates. They will set you back $100, but even if you do 1 alignment you will make that money back.

[Hoyt Clagwell]

The car is up on blocks right now and will be for a few weeks so I can't remeasure at this time. What I find perplexing is that my previous set of wheels/tires wore very evenly except for some slight extra wear at the very inside edges and I got the full life out of them. When I switched tires/rims, I got severe tire wear on those inside edges.
Nothing has changed since installing the new wheels. The suspension is a stock set up aside from poly bushings. Tie rods and control arms are new (Meyele HD, 3 years ago)
I don't think that it's a camber issue as it is stock and while I can't measure it, visually there looks to be very little camber in the front and the wear on the tires is not feathered at all. The wear is very localized and extreme.
Anyway, my plan is to get new tires and remeasure and re-align the front end. Then this time, I will keep a very close watch on the tire wear and if I see any unevenness, I'll take it to a shop. One reason I am avoiding shops is that the ones I know an trust don't want to work on a 24 year old BMW so I would have to take a chance on an unfamiliar shop.

[dbarton62]

The car is up on blocks right now and will be for a few weeks so I can't remeasure at this time. What I find perplexing is that my previous set of wheels/tires wore very evenly except for some slight extra wear at the very inside edges and I got the full life out of them. When I switched tires/rims, I got severe tire wear on those inside edges.
Nothing has changed since installing the new wheels. The suspension is a stock set up aside from poly bushings. Tie rods and control arms are new (Meyele HD, 3 years ago)
I don't think that it's a camber issue as it is stock and while I can't measure it, visually there looks to be very little camber in the front and the wear on the tires is not feathered at all. The wear is very localized and extreme.
Anyway, my plan is to get new tires and remeasure and re-align the front end. Then this time, I will keep a very close watch on the tire wear and if I see any unevenness, I'll take it to a shop. One reason I am avoiding shops is that the ones I know an trust don't want to work on a 24 year old BMW so I would have to take a chance on an unfamiliar shop.

If you are anywhere near Freelton Ont. I can point you to a good alignment guy.

[IndianaRoadster]

Maybe the tire treadwear rating on your latest tires were more high performance, thus wear faster than your old tires.

[Hoyt Clagwell]

If you are anywhere near Freelton Ont. I can point you to a good alignment guy.

Thanks. That's close to 2 hours SW of me although, if he can do it while I wait, it's not entirely out of the question. There is a shop not too far from me that a lot of my neighbors use and speak highly of. They do alignments but I haven't asked them if they would work on my 23 year old BMW.

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Maybe the tire treadwear rating on your latest tires were more high performance, thus wear faster than your old tires.

That wouldn't explain the drastic wear seen only on the innermost edge of the tire. It's very dramatic. From normal wear on 95% of the tire to down to the chords on the inner 1 inch.

[dbarton62]

Thanks. That's close to 2 hours SW of me although, if he can do it while I wait, it's not entirely out of the question. There is a shop not too far from me that a lot of my neighbors use and speak highly of. They do alignments but I haven't asked them if they would work on my 23 year old BMW.

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That wouldn't explain the drastic wear seen only on the innermost edge of the tire. It's very dramatic. From normal wear on 95% of the tire to down to the chords on the inner 1 inch.

He setup my E85 to my specs. Good guy.
Worth looking into.

http://canalignment.com/

[Hoyt Clagwell]

He setup my E85 to my specs. Good guy.
Worth looking into.

http://canalignment.com/

Thanks. I'll look him up if I can't resolve the issue myself. I'm willing to do the 4 hour round trip if he will set an appointment and do the alignment while I wait.

[MartyBtoo]

It's possible that the tire construction caused them to deflect differently under the same sideload. They could also require a different installed pressure due to the difference in rim width or tire profile. There's no easy way to be sure. I will say that I have always used Continental tires on the stock rims, and I could definitely feel the difference when they upgraded the sidewall construction (perhaps to more closely resemble the Michelin Pilots).

[dbarton62]

Thanks. I'll look him up if I can't resolve the issue myself. I'm willing to do the 4 hour round trip if he will set an appointment and do the alignment while I wait.

If you do decide to head this way, look me up, we can go for a tour of the escarpment roads while your car is being worked on.

[Hoyt Clagwell]

It's possible that the tire construction caused them to deflect differently under the same sideload. They could also require a different installed pressure due to the difference in rim width or tire profile. There's no easy way to be sure. I will say that I have always used Continental tires on the stock rims, and I could definitely feel the difference when they upgraded the sidewall construction (perhaps to more closely resemble the Michelin Pilots).

They're Toyo Proxys. 225/50 on a 17 X 7.5" rim. (They came with the rim.) My previous wheels that gave me no trouble in regards to wear, were Michelin Pilot Sports. 225/45 on a 16 X 7" rim.
I have no experience with this brand so anything is possible.

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If you do decide to head this way, look me up, we can go for a tour of the escarpment roads while your car is being worked on.

'sounds good.

[KeysCoupe]

You really need for an alignment specialist set up your car to stock (or close) specs. A string alignment gets you around the ballpark at best. As Randy stated, toe can be way off and the car can still drive nice. Have you lowered your car? If so, this requires a total alignment. Our cars rear toes changes with suspension travel.
-Donny

[Hoyt Clagwell]

You really need for an alignment specialist set up your car to stock (or close) specs. A string alignment gets you around the ballpark at best. As Randy stated, toe can be way off and the car can still drive nice. Have you lowered your car? If so, this requires a total alignment. Our cars rear toes changes with suspension travel.
-Donny

The suspension geometry is all stock except for the staggered wheels/rims. The front wheels are the same width as stock but different rim diameter and offset. The string set up I had with the old wheels worked beautifully with no meaningful unevenness in tire wear. If I can achieve that myself with the new wheels I will be quite happy. (although I've been doing a little research and I'm thinking that slight toe out may be preferable to slight toe in.)

[MartyBtoo]

Most road racers run a little front toe-out because it improves the turn-in performance by making the inside tire work more, but the downside for street use is that it makes the car very darty, as any one-wheel bump will cause the car to turn in that direction. This kind of behavior gets old real fast.

[Cyclone03]

I can only offer tire wear insight.

Tread wear on the inside can be toe OUT or negative camber.

If you have excessive wear on the inside of the tire you do have an alignment problem.

[Hoyt Clagwell]

Most road racers run a little front toe-out because it improves the turn-in performance by making the inside tire work more, but the downside for street use is that it makes the car very darty, as any one-wheel bump will cause the car to turn in that direction. This kind of behavior gets old real fast.

'sounds logical. I find that in most cases more maneuverability equals less stability, which means that in the case of the former, you have to work harder to keep it between the lines.

[Hoyt Clagwell]

I can only offer tire wear insight.

Tread wear on the inside can be toe OUT or negative camber.

If you have excessive wear on the inside of the tire you do have an alignment problem.

Thanks. When I get the car down off the blocks I plan to use the much maligned string method to determine what I have. I will actually be glad if I measure it to have excessive toe because then I will know what the issue is. I really don't think that it is excessive camber for a couple reasons. 1. It's all stock geometery and though I have no means to accurately measure camber, visually there is very little in front and a fairly small amount out back. The rear tires are fine. 2. The wear is not feathered or tapered at all. It is extremely localized to only the inside inch of the tires.

If my measurements indicate a problem with the toe, I will make the necessary adjustments and monitor the wear very closely. At the first sign of a problem, I'll take it to a good alignment shop. 'probably the one suggested above. That's the plan for now anyway.

[Cyclone03]

I would strait edge the front wheels and check toe. The string method helps insure the steering wheel is strait.

[Hoyt Clagwell]

Just to follow up on this thread, after getting new front tires, Bridgestone Potenza, I did an alignment using the string on stands method. I was very meticulous about getting the string set up perfectly square and with the height of the string very close to the height of the center of my wheels. That way, I could place a machinist's rule under the string until it just touched and pretty much eliminate any errors due to not looking straight down on the string.

I also kept notes and when looking at my last notes, I realized that I had actually set the fronts with a little bit of toe out. As mentioned in the first post, it was not enough to cause any undue tire wear on my original rims and tires but that change drastically when I installed different rims.

This time, I set the toe-in so that the leading edge of the rim was 2mm further in than the rear edge. (or 1mm in from center). So far, I have put about 5k miles on the new tires and cannot detect the slightest bit of uneven wear. It's still very early days so about once a week, I lay down on the garage floor in front of the tires and give them a good inspection. It tracks and handles really well also.

I'd prolly not attempt this if I had anything other than stock ride height as lowering will introduce other changes and complications in geometry but with the OE geometry, where front toe is the only adjustable element, I find doing it myself lends a certain satisfaction not mention a heftier wallet.

In the meantime, I'll keep monitoring the tire wear very closely and report if any issues crop up.

[sleeperz]

Thinking along the lines of camber being incorrect....
I am wondering if you have the strut hats reversed, left vs right side? It is a poor-man's autocrosser trick for E36's where it causes camber to be pretty extreme.
I tried it and wore the inner edges of my tires in no time flat. I went back to stock with a new set of tires.

[rf900rkw]

If you flip the hats without readjusting the toe, you will end up with pretty extreme toe-out and burn out the tires in short order.

[BimmerBreaker]

He has a non-M, he can swap top hats all he wants without affecting the geometry