BMW M5 Forum and M6 Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
517 Posts
Discussion Starter · #1 ·
I had the Beast aligned at the dealership in summer 2009 after the installation of the Dinan Stage I suspension from the group buy. Around that time, I swapped out the front tires to some older but basically brand new Dunlop 8080's. Fast forward to summer 2010 and they were seeing some unusual wear, very heavy on the inside tread of both tires. I put on brand new Sumi HTRZIII's in Fall 2010 and now am observing again very strong wear just on the absolute inside of each tire, whereas the rest looks practically new (fronts usually wear far better than the rears, of course, and the wear rating of that tire is pretty decent).

I'm attaching the scan of my alignment as I suspect I may still have too much Toe in the front? Can the Total Toe being 0 degrees 14' cause this issue? Is total toe the same as cross-toe? I've seen the FAQ and all the good info posted here on OEM alignment specs, DINAN recommendations, etc. I actually gave that printout to the BMW service adviser and discussed the procedure with him. However, I didn't push to have the alignment done with only weight in the driver's seat, which is my usual mode of driving.

Anything else you guys see on this alignment spec sheet as being an issue? If I gotta go in again, I'll do it to save some wear on tires. Just did the rears in new matching Sumi III's also.

thanks!!

SP
 

Attachments

·
Super Moderator
Joined
·
4,850 Posts
Inner wear is a bad combination of toe and camber. Best to align it as you drive it w/r/t gas & passengers. Member bimmerule had a similar thread recently.
 

·
Registered
Joined
·
517 Posts
Discussion Starter · #4 ·
Inner wear is a bad combination of toe and camber. Best to align it as you drive it w/r/t gas & passengers. Member bimmerule had a similar thread recently.

Thanks for the heads-up on Bimmerule's thread, I missed it in my searching (probably because the title was for excess camber and I've seen that a million times). Much appreciated, I found it and it was helpful:

http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/170659-rear-tire-excess-camber-normal.html

thanks!

SP
 

·
Registered
Joined
·
517 Posts
Discussion Starter · #5 ·
Toe affects inner wear considerably more than camber. What troubles me is how much more negative camber is in the rear.
When you say "how much more", you mean how much more than the fronts? Or just the fact that it is a lot in general, -1 degree 45'?

BTW, does Caster ever matter on any of these tire wear concerns? I'm not really sure what Caster is, the angle off 90 degrees that the shocks make with the ground?

Looks like I thought my numbers after alignment in 2009 were "good", there is room for improvement here to lessen rear camber and front toe. I'll get in for another alignment and get it right this time, assuming the techs can get there with the adjustments on the suspension.

Thanks again,
SP
 

·
Registered
Joined
·
1,032 Posts
Those numbers look ok, especially the after numbers. I wonder if the front toe has changed since it was adjusted? Camber all looks ok, castor is the tendency for the front wheels to remain in the direction pointed, maxing out castor gives more stability and a more planted feel in front - racers tend to set max castor.
 

·
Super Moderator
Joined
·
4,850 Posts
I can only speak for stock suspension. On that you can only adjust front toe, rear toe, rear camber. Understanding caster is academic and if cross-caster is out, then you probably hit something and need new suspension components.

Assuming proper tire inflation maintenance (easier said than done), paying attention to the wear patterns on your existing tires (e.g. feathering, chewed up inner edges) tells you how to adjust your alignment for the next set. Note that at some point, optimizing for tire life may cost you some handling/stability.
 

·
Premium Member
Joined
·
13,589 Posts
When you say "how much more", you mean how much more than the fronts? Or just the fact that it is a lot in general, -1 degree 45'?

BTW, does Caster ever matter on any of these tire wear concerns? I'm not really sure what Caster is, the angle off 90 degrees that the shocks make with the ground?

Looks like I thought my numbers after alignment in 2009 were "good", there is room for improvement here to lessen rear camber and front toe. I'll get in for another alignment and get it right this time, assuming the techs can get there with the adjustments on the suspension.

Thanks again,
SP
Yep, rear to front. Caster is in regard to the steering self centering...dont worry about it.

too much Toe in = excessive Outer tire wear

too much toe out = excessive Inner tire wear


Increasing camber = more toe out

Decreasing camber = more toe in
 

·
Registered
Joined
·
381 Posts
BTW, does Caster ever matter on any of these tire wear concerns? I'm not really sure what Caster is, the angle off 90 degrees that the shocks make with the ground?
Not the shock. The upper outside suspension point and the lower outside point. In a side view the angle this make relative to the perpendicular to the ground.

With + caster, when you turn the wheels the inside tyre goes towards + camber and the outside tyre goes toward - camber. This is beneficial as the roll of the chassis does the opposite in a corner.

One gets the self centering effect as you are lifting the car on its tyres while the turning of the wheel. This also transfers weight.

This caster angle is low enough for radial tires that I do not see it causing the wear you are experiencing.
 

·
Registered
Joined
·
12,398 Posts
I tend to proselytize about toe.... you really want it set to the minimum of the BMW spec. BMW allows huge toe, which will give you 5k miles on a set of tires. Same tires set at the minimum will get you 20k...everything else equal!

Have it set to 0.02 on each, combined toe (ie cross toe) to 0.03 or so
 

·
Premium Member
Joined
·
13,589 Posts
I tend to proselytize about toe.... you really want it set to the minimum of the BMW spec. BMW allows huge toe, which will give you 5k miles on a set of tires. Same tires set at the minimum will get you 20k...everything else equal!

Have it set to 0.02 on each, combined toe (ie cross toe) to 0.03 or so
Just make sure you have toe in on the front and rear tires, and the insides will last tons longer.
 

·
Registered
Joined
·
131 Posts
You also have to make sure whoever is doing the alignment is not taking shortcuts. Most Beemers require 150lbs on the drivers seat , passenger seat & another 150lbs in the trunk when the alignment is carried out to get proper alignment. Most techs won't spend the time to add all the weight & it will compromise the the readings.
 

·
Registered
Joined
·
12,398 Posts
Just make sure you have toe in on the front and rear tires, and the insides will last tons longer.
Right. I should have been clearer....+0.01, 0.02 is positive toe or 'toe in'
 

·
Registered
Joined
·
483 Posts
Why? The rear toe is easily adjustable as it stands....

Well I guess I made that statement prematurely since I haven't looked into it yet. I'm assuming the M5 uses eccentric bolts? From previous experience those usually do not provide enough adjustment range once the car's start getting lowered.
 

·
Premium Member
Joined
·
13,589 Posts
Well I guess I made that statement prematurely since I haven't looked into it yet. I'm assuming the M5 uses eccentric bolts? From previous experience those usually do not provide enough adjustment range once the car's start getting lowered.

Yes. I have had up to 2.25 degrees negative camber and up to .35 toe in with room to spare. There's plenty of adjustment...one of the many benefits of not having that rotten semi-trailing arm suspension.
 

·
Registered
Joined
·
12,965 Posts
****************************
Dinan alignment specs, Stage 3:

"All Dinan suspension alignments are done with full fuel tanks and no weight inside the vehicle."

Front:

camber -1.5 +/- 0.5

caster 6.5 +/- 0.5

total toe 0.20 +/- 0.08

Rear:

camber -2.5 +/- 0.5

total toe 0.34 +/-0.15

Regards,
Jerry
 

·
Registered
Joined
·
35 Posts
Worn/soft front thrust arm bushings can cause the insides of the front tires to wear. I see this frequently on V8 E39s.

(indy BMW tech)
 

·
Registered
Joined
·
517 Posts
Discussion Starter · #20 ·
Worn/soft front thrust arm bushings can cause the insides of the front tires to wear. I see this frequently on V8 E39s.

(indy BMW tech)
Good info - thanks! In my case, I think that is not the issue since I installed new thrust bushings, arms, etc. when the Dinan Stage 1 suspension went in. May be worth just taking a look anyways.

thx
SP
 
1 - 20 of 20 Posts
Top