I recently had new tires installed along with 2 rear ball joints and front thrust arm bushings, tie rod, etc. Of course I had a 4 wheel alignment done afterwards, and all alignments were within specs accordiing to the computer readout. When I look at the rear tires, they seem to have excess camber (the outside edge is not touching pavement, see picture). The fronts are touching the ground fine. Anyone have similar experience? This is stock size 275/35/18 Bridgestone Potenza 960s.
Rear tire excess camber, is it normal?
1 - 19 of 19 Posts
Joined
·
6,531 Posts
If I had a nickel...
The BMW procedure for alignment calls for significant weighting in the seats. These weights lead to a significantly different contact patch than what you will see when the car has no load in it.
In addition, our cars have a significant amount of rear camber to begin with, much more than a normal car, simply because of the sport sedans that they are.
My advice, which you are certainly welcome to ignore, is to have your vehicle aligned with the normal weighting as you would drive it. In my case, this means that I have it aligned with no one in it except the driver. Further, if you do not track the vehicle, consider having them apply less camber. In the interest of saving tires, and since mine is used solely on the streets, I have it aligned with 0 rear camber (or as close as they can get).
d-
The BMW procedure for alignment calls for significant weighting in the seats. These weights lead to a significantly different contact patch than what you will see when the car has no load in it.
In addition, our cars have a significant amount of rear camber to begin with, much more than a normal car, simply because of the sport sedans that they are.
My advice, which you are certainly welcome to ignore, is to have your vehicle aligned with the normal weighting as you would drive it. In my case, this means that I have it aligned with no one in it except the driver. Further, if you do not track the vehicle, consider having them apply less camber. In the interest of saving tires, and since mine is used solely on the streets, I have it aligned with 0 rear camber (or as close as they can get).
d-
Same here but the tech told me NOT to do a 0 camber and I think mine was adjusted to 1.3. Before measurements were 1.9 on one side and 2.1 on the other side and my tires were chewed up in 15k miles. The tech was confident the new 1.3 will give me much more tire life.
Joined
·
3,553 Posts
Holy Cr-- Douglas, where ya been? Good to read yer back.
+1 on everything being said here. I am @ .6/.7 on the rear and have 20,000+ on my rear tires and am showing even wear.
Joined
·
6,531 Posts
Lots of work, and frankly, not a lot of new questions being asked. With limited time to devote I can only rehash the same answers just so many times
I'm pushing close to 20K as well with even wear...
Joined
·
3,553 Posts
Yup....The BMW specs are aggressive. From a factory perspective, your car is good. From a tire perspective, as has been stated, 5-10,000 miles...maybe.
Tire wear
Yes, you can make the tires last longer,
Just get a prius, they will last 80K miles!
Seriously, after 7-10k miles, my back tires are DONE. (and yes, worse on the inner edge). The first couple of years I took them off the rims and swapped them to the opposite side to wear more evenly. They did wear evenly, but were still toast before 15K miles.
What grinds me is that the fronts often have some decent wear left, but I usually change to a different brand, so they are not fully used....
oh well, another expensive part for the beast,
ssomed
Yes, you can make the tires last longer,
Just get a prius, they will last 80K miles!
Seriously, after 7-10k miles, my back tires are DONE. (and yes, worse on the inner edge). The first couple of years I took them off the rims and swapped them to the opposite side to wear more evenly. They did wear evenly, but were still toast before 15K miles.
What grinds me is that the fronts often have some decent wear left, but I usually change to a different brand, so they are not fully used....
oh well, another expensive part for the beast,
ssomed
And what is the rear toe and cross toe????
People commonly look at inner edge wear, and the obvious visual camber, and say "Aha, it's that german car camber".
Even shops do this.
But unless you dial the rear toe to 0.01, 0.02.. you will simply grind off the inner edges. It is the combination of camber and toe that kills tires.
BMW allows 0.00 to 0.08 for toe....WAY to big a spec,
I run minimum toe-0.01 each side, and -1.8 camber, and get 15-18k from PS2s, but high speed highway miles- not stoplight racing.
Someone will bring up the fact that for race alignment you want a bit of toe to help turn in. I agree. Don't use the above advice on your racecar:noSMG:
A
Yes.
Joined
·
6,531 Posts
Not to oversimplify this, but I'm going to anyway:
In order to have your tires wear evenly and achieve reasonable tire life, 2 things must be the case: the tires must be flat to the ground when the vehicle when the vehicle is driven and the tires must roll along the same line as the vehicle. Doing anything other than this and you will either a) wear the tires out on 1 edge first, and/or b) scrub the tread off the tire at an increased rate.
BMW sets aggressive specs for the vehicle because they expect it to be driven hard. If you are occasionally drag racing the kid down the street, but otherwise driving it to work, that doesn't count. If you live in the country with twisty road and occasionally you drive them at something faster than the speed limit, that doesn't count. If you are on a dedicated race track and are actively competing with other drivers for the fastest time, then THAT counts.
My point is this: For every mechanical device there are a certain set of use assumptions. Those assumptions drive the parts, design, and set-up after the fact. Deviate significantly enough from the use assumptions and the set-up parameters no longer hold. I run very little camber on the rears and get great tires life, but at the expense of being able to track my car. Since I don't track it, this is ok.
There is no one set of "right" specs for the car. There is a "Right" spec for YOUR car and YOUR driving, but not in general.
d-
In order to have your tires wear evenly and achieve reasonable tire life, 2 things must be the case: the tires must be flat to the ground when the vehicle when the vehicle is driven and the tires must roll along the same line as the vehicle. Doing anything other than this and you will either a) wear the tires out on 1 edge first, and/or b) scrub the tread off the tire at an increased rate.
BMW sets aggressive specs for the vehicle because they expect it to be driven hard. If you are occasionally drag racing the kid down the street, but otherwise driving it to work, that doesn't count. If you live in the country with twisty road and occasionally you drive them at something faster than the speed limit, that doesn't count. If you are on a dedicated race track and are actively competing with other drivers for the fastest time, then THAT counts.
My point is this: For every mechanical device there are a certain set of use assumptions. Those assumptions drive the parts, design, and set-up after the fact. Deviate significantly enough from the use assumptions and the set-up parameters no longer hold. I run very little camber on the rears and get great tires life, but at the expense of being able to track my car. Since I don't track it, this is ok.
There is no one set of "right" specs for the car. There is a "Right" spec for YOUR car and YOUR driving, but not in general.
d-
Doug,
what specs are you running front and rear on your car, both camber and toe? I dont track my car just recently replaced tires, went up a bit in size 285/35 rear 255/40 front and want to align it soon. any help is appreciated. thanks
Joined
·
6,531 Posts
Heck of a good question - I'll need to pull the documents from my last alignment. I won't be home again until Friday, so please shoot me a PM to remind me to get them to you.
d-
1 - 19 of 19 Posts
Join the discussion
