Right pull on Pilot Sport A/S

I just had the OEM ContiSportContacts on my 2003 330i SP replaced with same-size Michelin Pilot Sport A/S, on the same 68M wheels.

Alignment was checked shortly before this at a BMW specialty shop, and was OK.

With the Contis, the car tracked straight, except for the expected left/right pull based on road camber. On a flat road it tracked perfectly straight.

With the A/S, it pulls noticeably but not severely to the right, even on a flat, non-cambered road. Tire pressure is 32/38, per the door jamb placard.

I've heard of this before and seen it attributed to "radial pull". It's not severe, but I like it to track perfectly straight. Can the toe-in or other alighment be adjusted slightly to compensate for this and make it track straight? I wouldn't mind even if it shortened the tire life somewhat.

If the alignment is correct then I would give the tires a chance to break-in a little bit.

If you still have this issue as severely at 500 miles I would have it checked out but if it eases up a little bit then I would wait until you have 1000 miles to see if it gets better.

My best guess though is the tires are probably fine and your not used to the car tramlining *as much* and following the grooves as in comparison to the Conti's. The Conti's don't tramline nearly as much as any other tire I have had on my car (and I've had at least 4-5 different tires on my car).

Though it sounds like you are aware of these type of issues, unless you've actually experienced it first hand it might feel strange.

I am still surprised by how much my car tramlines when I switch tires . . .

The Pilot Sport A/S drives VERY differently for the Pilot Sport. If it were not for the exorbitant cost, I'd recommend it to the more comfort oriented performance driver.

Originally Posted by Nick325xiT 5spd

The Pilot Sport A/S drives VERY differently for the Pilot Sport. If it were not for the exorbitant cost, I'd recommend it to the more comfort oriented performance driver.

Yes for an ultra high perf tire, the A/S has a fairly soft and quiet ride. Wet traction is excellent. However turn-in and transient response is more sluggish than even the ContiSportContacts, a mid-grade summer tire.

But the only characteristic that really bugs me is the persistent mild right pull (not the road-groove tramlining). I'll give them another 1,000 mi. to break in.

The front wheels are currently in the middle of the toe-in tolerance band. I was just wondering if a little more left toe (but still within the band) would be compensate for the mild right pull.

Try upping the front air pressure. It will reduce under-steer and the tendency of the front end to push. Which is what I think you are experiencing.

Originally Posted by ObD

Try upping the front air pressure. It will reduce under-steer and the tendency of the front end to push. Which is what I think you are experiencing.

Thanks I'll try more presssure. However my main problem is a mild persistent right pull even on flat roads, not push (understeer).

However if more pressure improves turn-in and transient response without making the right pull worse, or unduly degrading ride quality, that would be good. I'll try it.

Originally Posted by joema

Thanks I'll try more presssure. However my main problem is a mild persistent right pull even on flat roads, not push (understeer).

However if more pressure improves turn-in and transient response without making the right pull worse, or unduly degrading ride quality, that would be good. I'll try it.

The right pull maybe the understeer is all I'm suggesting. The rear end torque could be plowing the front end. I know by upping the pressure I reduced tramlining during the tire break in. I find the SP suspension very sensitive to air pressure and I can actually feel the difference in a 1 or 2 lb change.