Bump Steer/Loose Steering

[GettinFishy]

Hello Guys,

I have a 2009 BMW 135i and latley the steering has acted funny. Its almost like the steering is super loose, and when I say that I dont mean play in the steering wheel. I mean when the roads dips the car with pull hard to that side, when I hit small bumps (even the reflectors on the road) the steering wheel pull hard. Every bump/dip in the road the steering will just pull to that side. The only things that have changed are I had my car coded, new rear tires, and downpipes put on. Any ideas?

[Chandon]

had this issue many times including today..
hit the reflector on the road when turning left at a traffic light and steering wheel pulled pretty hard..

[IEDEI]

get a good alignment first.

[GettinFishy]

My cars steers straight when going down the road.

[lowbudgethero]

alignment and what type and size tires are you running?

[dcaron9999]

Sounds like a case of tramlining, brought on by new tires, and perhaps exagerated by mismatched front and rear tires...

[rking117]

Originally Posted by dcaron9999

Sounds like a case of tramlining, brought on by new tires, and perhaps exagerated by mismatched front and rear tires...

+1

[Tomas]

Checked tire pressure?

[drcollie]

What's the mileage on your car? Control Arm Bushings go south on all BMW's at around 70K miles, and need to be replaced to restore the steering feel. I've had BMW's that needed replacement at 50K miles and as long as 90K, but they have all needed them at some point. If your mileage is low, say 30K, you may have one bad control arm, that's not unheard of.

[GettinFishy]

My car currently has 54K miles. Front tires are the same ones that it came with from dealer, I think there Bridgestone potenza rfts. Tire pressure is fine, but the steering wheel just seems to want to jerk at every little bump it dip in the road.

[IEDEI]

Originally Posted by GettinFishy

My car currently has 54K miles. Front tires are the same ones that it came with from dealer, I think there Bridgestone potenza rfts. Tire pressure is fine, but the steering wheel just seems to want to jerk at every little bump it dip in the road.

did you get an alignment? you really can't even begin to investigate this until you do and see if it fixes the problem. most steering issues are caused by bad alignment.

[drcollie]

Originally Posted by GettinFishy

My car currently has 54K miles. Front tires are the same ones that it came with from dealer, I think there Bridgestone potenza rfts. Tire pressure is fine, but the steering wheel just seems to want to jerk at every little bump it dip in the road.

You've got a little bump steer going on. At 54K check the Control Bushings, I suspect that's it. If you are not real handy, run it by the BMW Service Dept and they can tell you in short order if the bushing are bad. They're a pain to install, so unless you are handy and have an afternoon to kill - then see the dealer.

Good luck,
Duane

[bbbbmw]

Originally Posted by drcollie

What's the mileage on your car? Control Arm Bushings go south on all BMW's at around 70K miles, and need to be replaced to restore the steering feel. I've had BMW's that needed replacement at 50K miles and as long as 90K, but they have all needed them at some point. If your mileage is low, say 30K, you may have one bad control arm, that's not unheard of.

The lower control arms are also called thrust arms - and the bushings do wear out. Many people replace them with bushings from the M3, as they are a bit more durable. The dealerships are known to be fairly expensive for this replacement (if not covered by warranty), so you might want to check with an Indy shop.

[GettinFishy]

If it makes any difference I noticed the cars steering goes all over the place when applying brakes. It'll pull back and forth pretty good. I'll run it by the dealer and have them check the bushings. Thanks everyone.

[rlmeskimen]

I know this is old, but wondering if you found out what the problem was?

I have a 2011 135i with M Sport that I rcently bought used. 47k miles. I put new brakes all the way around, new tires (Oem RFT) and alignment all done by BMW. It is out of warranty so all maintenance is out of my pocket.

Here is my issue: It now drives straight with no pulls right or left. Steering wheel is centered. Under hard acceleration, car feels like it pulls to the left and immediately when letting off, car quickly goes right. Alignment was done Saturday by BMW and I specifically asked if alll suspension looked good. Said all looked fine. I see no play in tie rods and I can not physically move or see any play in control arm or thrust arm bushings front or rear. Tire pressure is even across rear at 39 PSi and across front at 36psi. I roadraced motorcycles for many years so I have solid mechanic abilities.

Going to take it back to them but hoping to have some idea of the cause so I can limit costs. I can do most any suspension work if I know where to start troubleshooting.

Thanks for any help or guidance.

Ryan

[MightyMouseTech]

Are you sure both front rims are on the front and both rear rims on the rear? Sounds like mismatched offsets left to right.

[rlmeskimen]

Originally Posted by MightyMouseTech

Are you sure both front rims are on the front and both rear rims on the rear? Sounds like mismatched offsets left to right.

I will check for sure, thanks.

For tires, I have 225/40 on the front and 255/35 on the rear. Tires were brand new Saturday.

[Solo_M_Tech]

ALIGNMENT!!!!!! Have your toe settings checked. Aggressive toe out or 0 toe will make this more apparent. I run -2* camber with 0 toe and my car does this, not extreme, but it does. The more camber/Toe you add the more extreme the effect. Get a new alignment.

[rlmeskimen]

Originally Posted by HooningB2G

ALIGNMENT!!!!!! Have your toe settings checked. Aggressive toe out or 0 toe will make this more apparent. I run -2* camber with 0 toe and my car does this, not extreme, but it does. The more camber/Toe you add the more extreme the effect. Get a new alignment.

Thanks Hooning.

[rlmeskimen]

Verified the front rims are the same width and the rear rims are the same width. Good there.

I have attached, maybe, my alignment specs.

Again, Thanks for any and all advice. It is much appreciated.