Alignment Spec

[MaximusB]

Here is the story:

Not too long ago I got two new rear tires and while at it I had the shop fill my two fronts with nitrogen. Immediately afterward I noticed my car had a minor vibration on the highway. I took it back and they rebalanced all four wheels and said one of my front wheel was off. I found that odd because all they did was let the air out and refilled with nitrogen. Either way, they rebalanced the wheels but the vibration was still there but not as noticeable. I would only notice it if I go above 120km/hr on the highway and no vibration if I'm on new pavement.

I don't drive my car often and two weeks ago I decided to take my car to another tire shop to have the wheel balance checked. This shop said one front wheel was off by 0.25oz and one rear was off by 0.75oz. They rebalanced all four and said everything looks good, rims are true, road force is within spec, thread wear looks even.

Fast forward to last week. I finally had a chance to hit the highway and I THINK I still have a slight vibration and also out of no where I noticed my steering wheel isn't pointing straight. Odd since I don't recall hitting any potholes and no one else drives my car. But no big deal, I took my car in today to get an alignment done. Steering wheel is now pointing straight but my car would slowly drift to the right if I let go of the wheel. I called the shop back and they insisted the alignment spec is good and my car should track straight. It was near closing time so I couldn't drive back in time. They told me to bring it by first thing Monday and they'll swap my front tires around to see if it caused by my tires.

Here is the alignment print out:


Now my question is:
- Based on the current spec, should my car be drifting to the passenger side?
- If the vibration is still there, what else could cause that? My rear tires are brand new with a 2017 manufactured date. Fronts were made in 2012, so could it just be that my front tires are old and need new ones? I don't mind getting new front tires but I want to get to the bottom of it before I do. I'm doing a road trip next weekend and I need to make sure my car is safe.

[shimmy23]

Your specs could be dialed in a little better but you shouldn’t have vibrations on your current setup.

Take it to another shop? Is this shop familiar with the e9x chassis?

[MaximusB]

They should?? My bmw dealer recommended them.

I took the car on the highway tonight and I think all the vibrations are gone. Took the car up to 140km/hr. On certain stretch of the highway I was felt the steering wheel pulsating, not a shake/vibration. Could it just be feedback from the road surface?

[MaximusB]

Originally Posted by shimmy23

Your specs could be dialed in a little better but you shouldn’t have vibrations on your current setup.

Take it to another shop? Is this shop familiar with the e9x chassis?

Is it normal for the car to drift slowly towards the right side? On the highway it seems to drive straight, but around the city it tends to drift.

[deansbimmer]

It sounds like you have a worn front suspension component allowing some play.

[MaximusB]

Originally Posted by deansbimmer

It sounds like you have a worn front suspension component allowing some play.

Thanks! You're always a great help and I really appreciate your feed backs.

What should I check for if something is worn? Also I noticed that my right caster is set further back, which could explain for the slight pull to the right. If the caster is not adjustable what could I do about it?

I pulled out my previous alignment print out from 2016 and the caster were both at 7.15.

[deansbimmer]

I'd check the control arms and the steering rack for play and anything unusual.

It's normal for some shops or techs to set the caster to allow a slight right pull on roads. This is done for safety so a driver won't accidentally drift into oncoming traffic. However, since there is no provision to adjust caster on these cars you probably have either a worn upper strut mount or suspension arm(s).

Some shops will let you tell them what you want the specs to be. Not all shops can or will align an M3 because it requires loading the car with ballast to a specified weight and not all shops are equipped or willing. The big chains around here won't do them (NTB/Firestone/Goodyear/etc).

[MaximusB]

Originally Posted by deansbimmer

I'd check the control arms and the steering rack for play and anything unusual.

It's normal for some shops or techs to set the caster to allow a slight right pull on roads. This is done for safety so a driver won't accidentally drift into oncoming traffic. However, since there is no provision to adjust caster on these cars you probably have either a worn upper strut mount or suspension arm(s).

Some shops will let you tell them what you want the specs to be. Not all shops can or will align an M3 because it requires loading the car with ballast to a specified weight and not all shops are equipped or willing. The big chains around here won't do them (NTB/Firestone/Goodyear/etc).

Great! I'm taking my car back in tomorrow for them to recheck everything. I'll ask them to pay attention to those areas.

Another question, does the steering angle sensor need to be reset after an alignment?

[deansbimmer]

No need to reset SZL afterwards.

[MaximusB]

Originally Posted by deansbimmer

I'd check the control arms and the steering rack for play and anything unusual.

It's normal for some shops or techs to set the caster to allow a slight right pull on roads. This is done for safety so a driver won't accidentally drift into oncoming traffic. However, since there is no provision to adjust caster on these cars you probably have either a worn upper strut mount or suspension arm(s).

Some shops will let you tell them what you want the specs to be. Not all shops can or will align an M3 because it requires loading the car with ballast to a specified weight and not all shops are equipped or willing. The big chains around here won't do them (NTB/Firestone/Goodyear/etc).

Got everything corrected.

I took my car back to the shop and the Owner test drove the car. He agreed that I'm not crazy lol and my car does have a slight pull to the right. He put my car back on their rack and adjusted the front camber and toe. They didn't pay too much attention to the steering components but I'll make a note and will have that checked the next time I'm in for a service.

Looking at the new spec, it looks like he added he took out 0.1 degree camber on the right and added 0.3 degree on the left. The toe angle got changed by 0.01in on the right and 0.02in on the left. Everything is still within spec.

Took my hands off the wheel at 130km/hr on the highway and the car was going as straight as an arrow, and with no vibration except for road feedback I could feel on the steering wheel here and there. Even at low speed on a side street the car only drifts slightly if the road is uneven.