driving back from Vegas today I was showing my daughter how amazing the car is. I was doing 120 MPH on a two lane back road and with no hands on the wheel the car just tracked straight and smooth as could me. This is with 21 inch rims on. Your car should not be riding rough but just going smooth. Maybe the tires are getting worn down.

 

possibly a flat tire? if you have run flats hard to tell.

 

Run flats on an M5?
I dont thinks so........

 

The computer will let you know if your tire is getting low. A big warning comes up

 

Ya- I would check the tire pressure all the way around.

 

So what to do now? I can't imagine the service people did anything to the front end and on the invoice receipt I noticed something about the steering angle sensor.. That would be the only item related to the problem. Any thoughts? Any other problems coming from symptoms for a "rougher" ride coming from the front end?

Thanks in advance.

Sorry for the long post...

Can you please elaborate a bit more on "rougher" ride, so we will be able to understand it and reply acordanly.
Thanks

 

by "rougher" ride i mean it feels like you're on a cobblestone road almost @ higher speeds. i had a friend in the passenger seat on the drive up but didn't go over say 80 and it was less pronounced. my drive home was solo and cruising along above 80 you can almost noticeably see the dashboard vibrate and rumble and feel the engine kind of chugging like a diesel.

as for the tire pressures, i do have the 20in rac's and if the service guys did put too much air into (not sure if they did inspect that or not) that would be something to look into. however are these cars that sensitive to things like that? i used to be able to "cruise" @ 120+ and get completely speed-blind and now feels like i'm driving a horse-n-buggy down a backstreet of beirut... (ok maybe not that bad but compared to what i was used to it's definitely worse...)

 

By your discription, it sounds like you may have to get your wheel balance checked up, as soon as possible.

 

Funny you mention this, I recently had a M5 replacement car whilst mine was getting a scratch fixed, the car was 4 months newer than mine, but it felt smoother, it also sounded quieter, not sure if that was because this car had different software, or that it had extended leather and not full leather like mine, but my car certainly feels different, not as smooth. I actually prefer the sound of my car over the loan car. I also have a strange noise around 20Mph but the dealer think that is most likely to do with the tires, they checked it out and found nothing, I'm nearing the end of those tires so am taking it to a track at end of next week, so if something is wrong with my car, I'm expecting it to show its head then...

I like to think that my car is slightly more hardcore than the loaner, which only had 6K on the clock, mine has 13K miles.


Personally I wouldn't worry too much, ask the dealer to check it, but if something's goes wrong, I'm sure your car will let you know...

 

nothing really noticeable in engine sound at idle just more on cruising.

as for the wheel balance or bent wheel etc., the dealer had it for 2 days and only put on 2 miles for the roadtest. can they really have done any damage to make a difference before and after is the question...

 

got the wheels rebalanced and alignment done and still nothing... i even had it done at a reputable service shop that i normally go to as to avoid the dealer for now.

i know i'm not going crazy as i had a friend drive my car as i sat in the passenger seat and the "rough" ride or rumble is particularly noticeable above 65mph and 4500 rpms. you can literally see the headlights (obviously @ nite) flicker markedly up and down ahead of you and if you put your head back on the headrest it's as tho you were on one of those massage chairs at the sharper image. noticeable rumble coming from the floor to your feet as well. i can only imagine perhaps it's the engine? after 16k miles and having no problems it comes up after taking it to the dealer for one oil change and SMG recall??

any new thoughts?

 

got the wheels rebalanced and alignment done and still nothing... i even had it done at a reputable service shop that i normally go to as to avoid the dealer for now.

i know i'm not going crazy as i had a friend drive my car as i sat in the passenger seat and the "rough" ride or rumble is particularly noticeable above 65mph and 4500 rpms. you can literally see the headlights (obviously @ nite) flicker markedly up and down ahead of you and if you put your head back on the headrest it's as tho you were on one of those massage chairs at the sharper image. noticeable rumble coming from the floor to your feet as well. i can only imagine perhaps it's the engine? after 16k miles and having no problems it comes up after taking it to the dealer for one oil change and SMG recall??

any new thoughts?

This sounds like it might be a bent wheel.

 

Talk to your SA and get the Lead Technician to go on a ride with you at those highway speeds. If it is as pronounced as you say, and the Lead Tech is a reputable and knowledgeble man, he will know what is going on a fix your car. It sounds like a real problem that needs to be fixed.

 

i had another shop rebalance the wheels so don't think it could be a bent wheel otherwise it would not have balanced properly?

 

A road-force balancer might pick up on a problem with a bent wheel since it actually runs a pressure roller against the tire. If it was just a free-spinning balancer, they might be able to get a bent wheel to balance but it's never going to run correctly on the road.

Have you put the car sideways even one in a hard slide? Especially with the tires locked up at all? That could have created a flat-spot. You would normally be able to roll slowly and feel a flat spot on the tires, but if you ever locked up your tire(s) hard you could have created a flat spot...even a little one...and ruined the tire(s).

You asked about "are the cars really that sensitive." YES. It's not so much the car, which has a very tight suspension anyway, but 19" and 20" wheels with low-profile tires are simply more sensitive to tire balancing. Your RAC Monolites are probably not bent...Ralph & Chuck could probably comment on just how strong these wheels are. I remember Chuck telling me that I would probably break something in the car's suspension before I bent one of these wheels other than just curbing the outside of it.

 

You might need to rebalance your wheels...or it could be a flat spot on your front tires, or prehaps defective tire?

 

Thanks for all the replies.

Took it into the dealer again (this particular dealership has been notorious for complaints) and test drove it with a foreman/mechanic to recreate the problem. He noted it to be a "violent vibration" obviously noticeable. His first guess was perhaps a faulty tire or one about to go. As per James' aforementioned post about a flat spot putting the car sideways I surely have not done so. After the car was serviced they did put a few miles and that's my main gripe- the car was "almost" perfectly fine going in and getting it back for an oil change and smg recall should not have made this outcome.

in the future, any other recommendations of service/dealerships in LA preferably closer to the westside?

 

in the future, any other recommendations of service/dealerships in LA preferably closer to the westside?

I've tried most all of them when under warranty and I prefer Oscar Manso at Nick Alexander as a SA - really knows what is going on and is there to fix the problem - unlike my experiences at many other LA shops. True it is a further drive for me as well (think i could go to 5 others dealers that are closer to me) but I choose the service over the convenience factor anyday. Hope you get your problem worked out - I had a bent rim - ever so slight in the OEM inside front which gave me a rough ride until we figured it out and had it replaced. T.