Usually the wheel alighnment sorts this out. A few members have had theirs checked and they were a mile away from factory specification.

 

You're not by any chance running Pirelli P Zero RFT's are you, I am and they are absolutely crap IMO, they tramline dreadful and follow every little rut in the road surface giving that twitchy feel you describe, worst of all they aquaplane something rotten in heavy rain. Worst tyres I've had in the last 10 years without a shadow of doubt.

 

You're not by any chance running Pirelli P Zero RFT's are you, I am and they are absolutely crap IMO, they tramline dreadful and follow every little rut in the road surface giving that twitchy feel you describe, worst of all they aquaplane something rotten in heavy rain. Worst tyres I've had in the last 10 years without a shadow of doubt.

I have these tyres on also.. The car feels really twitchy over bumps. My traction control is constantly flashing and is cutting the power all the time over the bumpy bits!

 

Sounds like typical Pirelli tyres. I had them on my first 1er, for a week !

 

Thanks for the replies. Nope im running michelins PSS

235/35 front and 255/30 back.

I did go for wheel alignment and they did find that it was off from factory settings but it still twitches at the back. Dont think its dsc, wasnt going fast at all.

Could it be due to the adaptive suspension screwin up?

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Could it be the fact you're running too high tyre pressures... I remember I read you were using 41 psi on the rear?

 

Could it just be the fact that you are running 19" rims and only 30 profile rear tyres? There is not going to be much give in the tyre wall to take out any unevenness in the road.

 

My thoughts exactly.

 

Could it just be the fact that you are running 19" rims and only 30 profile rear tyres? There is not going to be much give in the tyre wall to take out any unevenness in the road.

^+1 add a high inflation pressure to that wheel and tyre combo and twitchiness over any sort of rough road is a given.

 

Ye probably its the low profile tires. Am running 39psi now instead of 41..

Thanks again for the pointers everyone!

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What's the difference in weight between new and old wheels?

I think 39PSI is still a little high, sounds like they're bouncing around a bit and the heavier? wheel weight is slightly changing the damping ability.

I had something similar going from 17-18s on an A3, the ride was dramatically worse, changed them back and the problem went.

 

What's the difference in weight between new and old wheels?

I think 39PSI is still a little high, sounds like they're bouncing around a bit and the heavier? wheel weight is slightly changing the damping ability.

I had something similar going from 17-18s on an A3, the ride was dramatically worse, changed them back and the problem went.

Hmm the new wheels are around 12kgs.

Will try a lower psi. Thanks

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I would go to 36 psi max, you might even have to drop to 34.

 

I have dropped to 33psi after slightly wareing the centre out more than the outers on my last set of tyres
Very marginal thou I'm monitoring the ware and very good so far
255/35/18s conti 5

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You're not by any chance running Pirelli P Zero RFT's are you, I am and they are absolutely crap IMO, they tramline dreadful and follow every little rut in the road surface giving that twitchy feel you describe, worst of all they aquaplane something rotten in heavy rain. Worst tyres I've had in the last 10 years without a shadow of doubt.

I have these tyres on also.. The car feels really twitchy over bumps. My traction control is constantly flashing and is cutting the power all the time over the bumpy bits!

Useful info - my lease company put an older gen Bridgestone RFT on the rear nearside, and a P Zero on the other (two separate punctures) and the composure at the rear has gone to pot. I fear damp weather is going to make the problem even worse.

 

Nasty I would want to mix different brands of run flats

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You're not by any chance running Pirelli P Zero RFT's are you, I am and they are absolutely crap IMO, they tramline dreadful and follow every little rut in the road surface giving that twitchy feel you describe, worst of all they aquaplane something rotten in heavy rain. Worst tyres I've had in the last 10 years without a shadow of doubt.

I have these tyres on also.. The car feels really twitchy over bumps. My traction control is constantly flashing and is cutting the power all the time over the bumpy bits!

Useful info - my lease company put an older gen Bridgestone RFT on the rear nearside, and a P Zero on the other (two separate punctures) and the composure at the rear has gone to pot. I fear damp weather is going to make the problem even worse.

What Rob says. I'd be on the phone to the lease company asking that one is changed & soon as!

 

Agree - madness to mix tyres at all, let alone across an axle.

 

Couldnt agree more but its a company car, and the policy is widespread. My colleague has 4 different patterns on her A4.

Basically Lex ring up KwikFit who then, at their leisure, ring the customer to arrange the replacement.

The first time they argued black and blue over the phone that there was no such tyre size as those fitted to the rear of the M Sport, even though I requested the exact tyre model that was currently fitted.

They eventually turned up unannounced 5 days later (in which time i'd done 400 miles @ 50mph max) and fitted the older Bridgestone. Second time around they just shrugged their shoulders and told me Lex do the same thing all the time, so I was getting a P Zero.

My only recourse would be to claim the mis-match is dangerous but then proving that is the case is the hard bit.

Alternatively of course, I could sabotage one or both of the tyres myself but that is obviously risky in itself. I'll just try and wear them out quickly I guess!

 

It helps if you know the kwik fit fitters. Never had that problem when I ran company cars.

They changed the tyres as & when required & sorted the lease company paperwork while doing so.

Get your car into BMW as ask them to check if they consider the vehicle safe? Then create merry hell with your HR & the lease company.

*******. The lot of them.

 

Ok, tried the car with various PSI, but car still feels weird. Been on 34 front 36 back, 36 front 38 back, and even 35/35s..

All this was done over 400 miles of driving (took the weekend off to a long distance trip).

What i noticed:
1. Car feels super floaty, as if a slight undulation will cause the car to move/tramline to the left.
2. If I lift my hands off the steering wheel, car pulls to the left 9 out of 10 times so I am crossing off that the road may be un even.
3. The car feels very unstable at only 120-140-kmh, even in Sports mode.

All this happens even after a wheel alignment is done. will post up the alignment figures up later for all to see.

This sucks, I've driven my stock mk6 GTi on that same road (and also many times with it on coilovers), it is must more stable and brings confidence. The M-lite that i have seems to give me the sweats when driving sporty in the highway

Question:
Can this be due to bad rack/adaptive suspension? Since it knocks, and groans over bumps and you can hear a loud "GRUuuuuuuuuukkk" sound when you turn the steering wheel left to right, right to left. (The same issue most adaptive suspension owners are facing). Will be going over to the dealer again tomorrow..

Really tempted to order a set of KW if it really solves this crap

 

Have you still got your original wheels/tyres?

Perhaps put them back on with recommended pressures and see if your over sized wheels perhaps are causing some abnormalities?

Worth a try before investing in suspension changes

Could be you also may have a faulty damaper perhaps?

 

Doesn't sound normal at all. Have the suspension components throroughly inspected before you change to KW (that would be insane a solution to a problem that shouldn't be there).

Cars always pull left a little because of the natural road camber so the test may not be such a godd indicator, but then again it may well be!

 

Nope, dont have the original wheels/tyres anymore. I dont remember the car feeling so floaty when i swap to the new set of 19" rims. It's just that this started to be noticeable past 2-3 weeks and i thought i was being paranoid.

I do suspect its a faulty suspension.. when i was reaching home after the 200mile drive, saw a bump ahead and tried going over it abit faster than usual and the knock (driver side, right hand drive) was so loud that it sounds as it it is falling apart ! :x

oh well, another trip to the dealer. why cant the car be fun to drive and own

 

Doesn't sound normal at all. Have the suspension components throroughly inspected before you change to KW (that would be insane a solution to a problem that shouldn't be there).

Cars always pull left a little because of the natural road camber so the test may not be such a godd indicator, but then again it may well be!

haha yes, will definitely get them to check again but i have a feeling that they willcome back saying 'its normal and BMW has no fix for this knocking thingy yet" response.

And yes i do agree that car may pull left a little but this is way too much. I let go my hands for 3 seconds and i am almost in the next lane already. The wheel doesnt turn though, just the car floats to the left as if im being blown from the side. hehe