E46 tramlining
Discussion
I've had my 2002 E46 M3 since March '11, it has covered 85k and is in generally good condition. I had an oil service and suspension bush inspection in August. I put 2 new Conti ContactSports M3s on the rear wheels (18") in September, the fronts are still Bridgestone RE050A about half worn. Since then I have noticed 2 things that may or may not be related. Tramlining is quite bad on the motorway and can be excessive under hard acceleration when overtaking on A roads. Also, there is tightening right-hand slip road where at about 70-80mph the traction control activates whether on the throttle or not, wet or dry. When touching the brakes at this point the ABS was instantly activated. The mechanic deemed my bushes to be fine all round. I have checked tyre pressues and they seem fine. Does your car tramline under acceleration? Should this be investigated further?
rossbraithwaite said:
I've had my 2002 E46 M3 since March '11, it has covered 85k and is in generally good condition. I had an oil service and suspension bush inspection in August. I put 2 new Conti ContactSports M3s on the rear wheels (18") in September, the fronts are still Bridgestone RE050A about half worn. Since then I have noticed 2 things that may or may not be related. Tramlining is quite bad on the motorway and can be excessive under hard acceleration when overtaking on A roads. Also, there is tightening right-hand slip road where at about 70-80mph the traction control activates whether on the throttle or not, wet or dry. When touching the brakes at this point the ABS was instantly activated. The mechanic deemed my bushes to be fine all round. I have checked tyre pressues and they seem fine. Does your car tramline under acceleration? Should this be investigated further?
Mine does tramline with strong cambers and this is exagerated under hard acceleration. It does so more than most cars I've owned but I wouldn't say its excessive. IMO if it has moticibly got worse since you changed tyres then that's your answer, you will get a lot of people telling you don't mis-match tyres but if they're are paired on each axle I can't see how this would increase tramlining.TC and ABS coming on sounds odd though, in the dry you really need to provoke the M3 TC and I've never seen the ABS light come on!
Big E 118 said:
Mine does tramline with strong cambers and this is exagerated under hard acceleration. It does so more than most cars I've owned but I wouldn't say its excessive. IMO if it has moticibly got worse since you changed tyres then that's your answer, you will get a lot of people telling you don't mis-match tyres but if they're are paired on each axle I can't see how this would increase tramlining.
TC and ABS coming on sounds odd though, in the dry you really need to provoke the M3 TC and I've never seen the ABS light come on!
There is no ABS light TC and ABS coming on sounds odd though, in the dry you really need to provoke the M3 TC and I've never seen the ABS light come on!
Big E 118 said:
TC and ABS coming on sounds odd though, in the dry you really need to provoke the M3 TC and I've never seen the ABS light come on!
Totally agree about the M3 TC; you have to be quite rough with it on a dry road. That is why I was surprised to see the TC light flashing in 5th gear on half throttle! ABS light didn't come on but I felt it when I touched the brake pedal.
Yes. I have taken that bend plenty of times without issue before changing the tyres, it has only happened since then. DSC/TC must be detecting some difference in rotational speed between the 4 wheels. I was surprised that the ABS deployed as soon as I feather the brake pedal though. The DSC must have assumed that I was about to crash and decided braking wasn't clever (there was a slower vehicle in front).
Buzzmeister said:
Yes. I have taken that bend plenty of times without issue before changing the tyres, it has only happened since then. DSC/TC must be detecting some difference in rotational speed between the 4 wheels. I was surprised that the ABS deployed as soon as I feather the brake pedal though. The DSC must have assumed that I was about to crash and decided braking wasn't clever (there was a slower vehicle in front).
Has it only happened the once then? I'd say that braking on a long, decreasing radius bend would change the weight distribution enough to have to kick in the DSC at that speed. There may also have been a bit of diesel down that caused less traction than normal. Try it again, see what happens!Big E 118 said:
Has it only happened the once then? I'd say that braking on a long, decreasing radius bend would change the weight distribution enough to have to kick in the DSC at that speed. There may also have been a bit of diesel down that caused less traction than normal. Try it again, see what happens!
No, it has happened twice. Once in the wet, on the gas (I thought fair enough even though I was in fifth). Once in the dry, off the gas. DSC had already deployed when I douched the brake pedal. I agree that in normal circumstance braking in that situation would not be ideal but I had lifted off the gas long before.Thanks for your response, I'll give it a good crack tomorrow evening. Not sure what to do if it continues to happen though as the M3 should eat that bend.
ghibbett said:
E46's are *extremely* sensitive to tyres. Get matching tyres on the front and I would happily bet a fiver the problem disappears.
ExactlyMine did the same, it had Continental M3 on the back and worn Michelin on the front. I have just put Conti M3s on the front and am amazed at the difference.
I had exactly the same issue on my 330ci after changing the rear tyres. It had always tramlined to an extent but had the DSC light flashing during (steady) cornering, with the car "feeling" very strange.
The fronts were the same brand as the new rears and had plenty tread in the centre but the edges were well worn. I had new fronts fitted and it felt like a new car, the DSC issues disappeared immediately.
The previous owner had some new front bottom arms fitted, so I assume the front tyre edge wear occurred with the previous arms (or perhaps just under inflation) as the new front tyres wore evenly over the life of them...
The fronts were the same brand as the new rears and had plenty tread in the centre but the edges were well worn. I had new fronts fitted and it felt like a new car, the DSC issues disappeared immediately.
The previous owner had some new front bottom arms fitted, so I assume the front tyre edge wear occurred with the previous arms (or perhaps just under inflation) as the new front tyres wore evenly over the life of them...
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