Motorway speeds and steering
- Thread starter ChillZ4
- Start date
RFT's, i drove the car back 100 motorway miles when i picked mine up and just thought what is going on here. Its simply that our roads are rubbish, slow lane is the worse. Had the car nearly a month now and starting to ignore/learn to live with the tramlining. Is annoying when your braking and the cars pulling you all over the road.
ChillZ4
I'm experiencing exactly the same, or I think it is. On a good smooth surface such as the outside lane the car requires constant minor correction, not that it's steering off course just that the wheel pulls left/right requiring 1/4" movement from left to right. Tramlining is a lot worse, crossing ruts, crossing centre white lines you need to be awake.
I've changed tyres to non RFT's and had a top notch full geometry test done and it's all in tolerance. Lowering my tyres to 30 rear and 28 front has helped (don't do this on the RFT's) . Fitting a ftrut bar has if anything highlighted it.
I'm now comfortable it's just a trait of the wide tyres, poor roads, and suspension system.
I'm experiencing exactly the same, or I think it is. On a good smooth surface such as the outside lane the car requires constant minor correction, not that it's steering off course just that the wheel pulls left/right requiring 1/4" movement from left to right. Tramlining is a lot worse, crossing ruts, crossing centre white lines you need to be awake.
I've changed tyres to non RFT's and had a top notch full geometry test done and it's all in tolerance. Lowering my tyres to 30 rear and 28 front has helped (don't do this on the RFT's) . Fitting a ftrut bar has if anything highlighted it.
I'm now comfortable it's just a trait of the wide tyres, poor roads, and suspension system.
Just a bit to offer here. If you have not had an alignment since you picked it up from the dealer, they have a bunch of settings in the alignment. Right after I had my first alignment the car felt very twichy with all the settings removed. I like the way the car handles now and so do the tires.
melbs said:
melbs - can you explain that statement of 'sticky steering' please?
Whatever is wrong with mine has deteriorated so it's either mechanical in toe in, camber castor, etc. or related to the EPS giging continous unrequired minor input. I jus t need to find out which, why and fix it for good.
OK so read all the threads on 'sticky steering' and I do not think that's it. This appears to be where temperature causes the steering to be stiff, lock up, etc.
My steering issue is very different and it's as if the steering motor were continually adding minor left and right inputs in. Actual turning, cornering, lock to lock, etc are all perferct. Today 100 miles of 70 to 80 mph on the motorway was tiresome an dironically the smoother the tarmac I found the worst it was
My steering issue is very different and it's as if the steering motor were continually adding minor left and right inputs in. Actual turning, cornering, lock to lock, etc are all perferct. Today 100 miles of 70 to 80 mph on the motorway was tiresome an dironically the smoother the tarmac I found the worst it was
I'm certainly no expert on steering, nor am I on "tramlining," but the February issue of Bimmer had a nice Tech Q&A tidbit on this subject.
A gent wrote in to ask, essentially, if the tendency of his car, a 2008 Z4 3.0si, to track with road irregularities was due to his RFT-Bridgestone Potenza REO 50As. He was also concerned if this would lead to early wear of the steering components.
The tech answered:
"Nice car! What you have described is called "tramlining"... (and) ...is very common on modern high-performance sports cars in general, not just the Z4, and is caused by problems with the road, not the car. To the extent that tires are a factor, it is their larger size rather than their run-flat capability. While would not rule out the possibility that tramlining may be affected by a change from run-flat tires to normal tires, think you're probably just going to have to steer through it when it happens. don't think tramlining will have any affect on suspension component wear."
I have no doubt that switching from RFTs to non-RFTs will improve the ride comfort, simply by default of the less stiff construction of the latter. But I am doubtful that tramlining is the sole fault of RFTs in and of themselves (they probably don't help though).
Anyway, that's somebody else's 2-cents... I just thopught it was interesting and worth sharing (I love the Tech Q&A secion in Bimmer).
Cheers.
A gent wrote in to ask, essentially, if the tendency of his car, a 2008 Z4 3.0si, to track with road irregularities was due to his RFT-Bridgestone Potenza REO 50As. He was also concerned if this would lead to early wear of the steering components.
The tech answered:
"Nice car! What you have described is called "tramlining"... (and) ...is very common on modern high-performance sports cars in general, not just the Z4, and is caused by problems with the road, not the car. To the extent that tires are a factor, it is their larger size rather than their run-flat capability. While would not rule out the possibility that tramlining may be affected by a change from run-flat tires to normal tires, think you're probably just going to have to steer through it when it happens. don't think tramlining will have any affect on suspension component wear."
I have no doubt that switching from RFTs to non-RFTs will improve the ride comfort, simply by default of the less stiff construction of the latter. But I am doubtful that tramlining is the sole fault of RFTs in and of themselves (they probably don't help though).
Anyway, that's somebody else's 2-cents... I just thopught it was interesting and worth sharing (I love the Tech Q&A secion in Bimmer).
Cheers.