[armanm]

The lease maturity date on my 2012 328i is coming up and I am taking it for a pre-inspection today at a local dealer.

Both rear tires, 18" Pirrelli P7 cinturato, seem to have weird wear patterns.
One half side of each tire has extreme wear while the other half has normal wear.
Is that normal, or would I be able to plead my case to the dealership?

Thank You!

[keylime503]

How old are the tires and how often did you get them rotateD?

[WilliCO]

Originally Posted by armanm

One half side of each tire has extreme wear while the other half has normal wear.

It's the inside half of each tire that has the extreme wear, right?

This happens because of the aggressive camber settings BMW uses in their alignments - the wheels are actually positioned such that they angle outward at the bottom a little. Somewhere I have a picture of my old E60 taken from behind, and you can actually see a slight slant on the rear wheels with the naked eye. It helps the cars handle as well as they do, but the inside edges do wear more quickly that way.

The camber adjustment, and possibly some need for an alignment, are likely your culprit. Keeping the wheels aligned is definitely on you, and I imagine BMW will consider the camber-related wear to be normal wear on a wear item and also your responsibility, but see what the inspector says.

You can definitely have the alignment done on a future BMW with a somewhat less aggressive camber setting, and that will help the longevity of your rear tires a bit. The car will feel a little different, may or may not bother you.

[armanm]

Originally Posted by keylime503

How old are the tires and how often did you get them rotateD?

AS far as I know the car was built April 2012, its been in my possession for 2 years and 8 months.

Do the rotate them when they get serviced? Because I have never specifically asked them to rotate it.

Also do you know if they swap front and rear tires when in service?

[armanm]

Originally Posted by WilliCO

It's the inside half of each tire that has the extreme wear, right?

This happens because of the aggressive camber settings BMW uses in their alignments - the wheels are actually positioned such that they angle outward at the bottom a little. Somewhere I have a picture of my old E60 taken from behind, and you can actually see a slight slant on the rear wheels with the naked eye. It helps the cars handle as well as they do, but the inside edges do wear more quickly that way.

The camber adjustment, and possibly some need for an alignment, are likely your culprit. Keeping the wheels aligned is definitely on you, and I imagine BMW will consider the camber-related wear to be normal wear on a wear item and also your responsibility, but see what the inspector says.

You can definitely have the alignment done on a future BMW with a somewhat less aggressive camber setting, and that will help the longevity of your rear tires a bit. The car will feel a little different, may or may not bother you.

Yes, it is the inside half of each tire.

Really? I find that BMW's have positive camber.

[WilliCO]

Definitely negative camber in my experience, and if you have a rear set worn on the insides, yours probably are too.

[HighlandPete]

It may not just be camber, toe settings can also add to the inner wear pattern. Add in compromised tire pressures and run-flat wear can be very weird.

HighlandPete

[Billfitz]

Originally Posted by HighlandPete

It may not just be camber, toe settings can also add to the inner wear pattern. Add in compromised tire pressures and run-flat wear can be very weird.

+1. Too much toe in will wear the outside of the tires, too little will wear the inside. If it's really off cupping will occur.

[Thumper333]

Originally Posted by armanm

Really? I find that BMW's have positive camber.

Nope, negative.




In addition to the improved corner handling characteristics with negative camber (within reason), it also affects high speed stability.

When a car begins to gain speed the body begins to act like a wing, this lightens the vehicle on the suspension, which then changes the camber towards positive. By running negative camber at a certain rate the engineers can have the suspension reach 0 camber (and the most possible traction with full tire contact patch) at high speeds. If you start with 0 camber, at 100MPH you will be at positive camber and have less contact with the road.

Not ideal at 100MPH.

It has been speculated that this noticeable design in BMWs (and many MBs and Audis) is due to the Autobahn in Germany however the reality is likely just the better driving dynamics from such a design.

Positive camber is for cars with massive downforce, they no longer lift at high speeds, but rather are pushed down against the ground at higher speeds. Obviously tuning for cornering will change the dynamic a bit but overall the plan is to have the car reach 0 camber at whatever point it needs the most traction.


Agree with everyone here, lots of factors could cause this. Toe out is probably unlikely but improper inflation coupled with the aggressive camber would make short work of tires.

Now that they are worn improperly, fixing the issue will do nothing. They will continue to wear in an uneven fashion.

I would see if they take a penalty on them at the inspection and then see what the cost of new tires is versus the penalty before you turn it in.

[keylime503]

Originally Posted by armanm

AS far as I know the car was built April 2012, its been in my possession for 2 years and 8 months.

Do the rotate them when they get serviced? Because I have never specifically asked them to rotate it.

Also do you know if they swap front and rear tires when in service?

No and no. BMW doesn't do any sort of tire rotation as part of scheduled service. I just passed 6000 miles on my F32 and I dropped by the local America's Tire store on the way back from work the other day to get a free tire rotation (even though I didn't buy the tires from them).