|
As I understand it, tramlining is a two-fold problem caused by front suspension geometry (the two front wheels never point in exactly the same direction - usually by design) and *difference* in right and left tire adhesion. Basically, the car goes more in the direction of the tire with the most grip. High performance tires tend to exhibit more tramlining for a couple of reasons (not an all inclusive list):
1. The tires are capable of more grip - and are therefore likely to exhibit more difference between left and right tire grip over undulating road terrain
2. The tires' contact patches are bigger, again creating the likelihood of more difference in side-to-side grip over undulating terrain
3. The tires' lower sidewalls means less compliance (i.e. more mechanical coupling) between the tread and the wheel, which exacerbates the phenomenon
It doesn't help that in general there is a correlation between high performance tires and the cars they are mounted to - the tires are usually installed on cars with more aggressive steering/suspension geometries. In general some straight-line performance (and tramlining immunity) is given up to increase performance in the twisties.
If your car has a lot of tramlining there are some things that can be done to improve it (undoubtedly not all-inclusive):
1. Change tires
2. Change tire pressure
3. Change the geometry of the car, specially toe in and camber
4. Install stiffer bushings to minimize the amount of geometry change that occurs when the tires fight each other
5. Change wheel offsets (but I think this is mostly just changing camber indirectly)
I'd start with tire pressure first. My 540's Dunlops go from no tramlining at 35 PSI to agitating amounts of tramlining at 36 PSI
__________________
'03 E53 X5 4.4i Topaz/Sand
'06 E90 330Xi 6MT Sparkling Graphite/Terra
'08 E92 M3 6MT Jerez/Speed Cloth/Carbon Leather <-- Evil Twin
|