[flukey]

I have a 2007 E90 335xi and under acceleration my car pulls to the right (passenger side) and the higher the speed the more "loose" or "unstable" the steering feels while accelerating.

This feeling became noticeable after I got my summer wheels mounted several weeks ago. I haven't driven much but I figured maybe I needed to wear in the tires a bit, but that hasn't helped.

During the winter I was running this setup:

18x8.5 +35 with 5mm spacers on all four corners
225/40R-18 Dunlop SP Winter Sport 3D

I am now running:

19x8.5 +30 with 5mm spacers only on the rear
235/35ZR -19 Hankook Ventus V12 evo K110 XL

Here are the facts...

1) My car does not pull left or right if I let it coast or if I use the throttle just enough to maintain speed
2) I have no problems with DSC or DTC
3) My wheels are balanced
4) My air pressure is 33-34 lbs on front and 38-39 lbs on rear
5) I have been running KW V3 with H&R Rear Sway Bar since the the end of last summer and have had no problems
6) At the shop that mounted my wheels they did not raise my car using the four point lift. They used the lift that you drive onto and has hydraulic lifts in the middle.
7) I do not hear any unexpected noises nor do I feel any shaking or shuttering. The car actually rides smooth, but it simply pulls to the right under acceleration.
8) Lastly, when braking, the car will maintain a straight line

I'm looking for any advice/comments and help is greatly appreciated. I assume I'll probably have to take into the dealership or a mechanic, but I'd like to know what things to ask the mechanic to look for or what I should be aware of.

Thanks!

[bradford]

More traction resulting in more torque steer up front? Generally not a problem with AWD cars, at least with my extensive experience with Audi Quattros, but I don't really know anything about the BMW AWD system. Does it use unequal length driveshafts up front?

Otherwise I'd say replace the rear suspension bushings with M3 ones. The OEM ones are crap and the rear wiggles all over the place under acceleration.

[huebert_jdn]

I've experienced the same thing in both RWD and AWD cars with low profile tires. It could just be that the grooves in the road are pulling it one way or another. My car does it all the time, the back end wants to jump out to the right, even on the highway sometimes. Try moderate pressure braking from about 35mph but take your hands of the wheel completely (keep them close of course!! and do it on an empty road). Also check to see if all your spacers are there and your staggered wheels were not miss matched when installed, a missing spacer or front wheel on the back will crank your car hard!!

P.S. I just had an alignment done, and it STILL pulls when I floor it...

[flukey]

bump. any other suggestions?

[The HACK]

When is the last time alignment is done?

[flukey]

Originally Posted by The HACK

When is the last time alignment is done?

Four wheel alignment was done when my winter wheels were mounted and the H&R Rear Sway Bar was installed (KW V3 had already been installed for a year). This was end of summer/early fall 2009.

[The HACK]

How many miles on the car?

EDIT: Before we go on a further wild goose chase with me asking one question at a time, I'm going to stop right here and give you MY best guess.

There are only a couple of reasons why the car would pull to one side consistently under acceleration on a BMW RWD or AWD. One would be alignment. But since you've had the car aligned last summer I'm going to have to rule that out. Two is a loose suspension bolt somewhere. But if you do not experience any pull with the winter tires that sort of rules it out, although not entirely...There can still be a loose suspension component allowing excess movement of the toe or camber, but with winter tires on the soft, pliable sidewalls disguised most of that.

Which leads me to believe it's possible that your front control arm bushing on the passenger side is shot. The only reason I ask about the mileage, is typically these bushings are good for anywhere between 30,000-50,000 miles. By 60,000 miles you'd be lucky if they still retain enough functionality that the car's front suspension hasn't completely just fallen off (exaggeration). If you have a higher mileage car, or a car closer to the end of the warranty, I wouldn't be surprised that a broken control arm bushing is allowing the control arm to move around enough to alter some alignment settings while the car is moving to result in the car pulling in one direction or another.

The other usual suspect on a BMW, the rear trailing arm bushing, is no longer deployed on the E9X platform.

[e90pilot]

Rear subframe bushings. You'll notice it under hard accel and during hard cornering. Get the M3 bushings. A lot of 335 guys notice this when they have stiffer suspension.

[flukey]

I only have 16000 miles on the car. I am lowered on KW V3 since about 7000 miles. Ive read on other forums, not necessarily an E90, that lowering can cause bushings to fail and can result in this type of issue. I've also read that I should try swapping the front and rear wheels on the drivers side and see if that helps things.

[flukey]

PROBLEM SOLVED:

Ends up like most of the research said.... if there are no other symptoms than WOT acceleration inducing pull its almost positively the tires.

After closely looking at my tires I realized the driver's side front tire was a Hankook Ventus V4 when I had ordered 4 Hankook Ventus V12. TireRack more than happily sent me the correct tire and pickup of the incorrect tire at no charge.

No more pull for me! Thank you TireRack!

Check your tire pressure and tire brand/model/size/etc if you experience my symptoms!