KOAN

I don't, but mine is a '96.

SwissCarrera

Thanks for all your comments chaps ! I will try out some of the advice given and let you know if i experience any success.

SwissCarrera

Ok - so here is the final explanation. I spoke to Gert at Carnewal, who said that a strut brace wouldnt make any difference, he advised that maybe my car was lowered to far - below RS ride height and bump steer and tramlining is more pronounced. So whilst on vacation my mechanic, raised the ride height by 10 mm and also checked the suspension gemetry , tracking etc. when i picked up the car, he said" its better, but not totally resolved, it your tyres, they are ****". Tyres are P - Zero's. Hmmm i thought and drove home. Sure enough tramlining and bump steer were still there, but not as bad as before. This weekend just passed i swoped my summer rims for my winter rims which have Michelin Snow tyres and what d'ya know, tramlining and bumpsteer completly gone. i understand that the p Zero's are designed to "run flat" and therefore have stiffer sidewalls and therefore "give" less. Needless to say when they are worn out i wont be replacing them with the same brand. Anyway thanks to Gert and to Angelo Pallavicini cars in Zurich.

Monique

I have plenty of tramlining but I know why. Rears are worn and fronts still 50%.

I always use Nitrogen for tires... minimizes the hot/cold differences. Get it from any aviation tire shop.

Monique

I have plenty of tramlining but I know why. Rears are worn and fronts still 50%.

I always use Nitrogen for tires... minimizes the hot/cold pressure differences. Get it from any aviation tire shop.

Leland Pate

Man o' man am I in this boat now.

I just installed a set of 18" twists on the 993 last week. As soon as I left the driveway it was real obvious. I'm glad I remembered this thread.

At first I thought it was due to the rear tires being completely shot (wire belts exposed) but today I had a new set of BFG TA/KD's put on the rear and it hasn't changed the tramlining. The fronts are ok. Maybe 65% left. The only real problem with the front tires is that they are showing signs of uneven camber wear on the insides.

I have sort of a complicated problem. I don't know if the tramilining is caused by the uneven tire wear on the fronts, differences in air pressure, or because of my low ride height (H&R springs).
My bet is it's a bit of all three.

I'm going to play with the air pressures and see if that helps. The roads here are no better than the town itself (sh!tty) and that makes it all the worse. This can't do because when I hit a change in the asphalt or slight bump/rut, the car goes veering off to either side. I can't let go of the wheel for fear of the thing flying into another lane.

By the way, it did not do this with my 17" cup II's. So, perhaps the problem lies more with the tire pressure/uneven tire wear than anything else.

Pete Lech

I know it is a different model, but on my '85 coupe, I put new rears on with 50% worn fronts and drove from LA to the Portland Parade. The trip was hell. The car would change 1/3 of a lane all on its own, especially as the gas level went down. I put on a new set of fronts up there, and the tramlining went completely away. Moral of the story is that the front tires are more important that you might think. One way to test this would be to add significant weight to the front trunk and see if it reduces the tramlining. If it does, changing the front tires could help solve the problem.

Father of 3

what pressure settings are you using?

seege

Leland your problem sounds pretty serious, you arent mixing tire models are you? If your fronts show uneven wear then you should do them now too. I'm assuming the uneven wear came that way and your car has a current alignment. Personally I would put the 17s back on until the 18s are all in order.
Good luck

STLPCA

OT: Chris
Target hot temps for MPSC are 32/36 F/R per Michelin. I set pressures using a pyrometer & invariably when I get the temps right across the tread, my hot pressures are in the low-mid 30s. I think your's are too high. IMO, the MPSC tend to get a bit slippery at higher pressures. Try dropping a few lbs (from your tires) - you might like it.

Brad '95 C4

Leland- I have previously run BFG KD's and they have a very stiff sidewall which contributes to the excellent cornering power. It does however also add to the tramline effect. That said, my issue was also compounded by aggressive -2.5 camber frt & rear.

CEBoyd- Gotta love the cornering you get with aggressive camber settings!

Cheers, Brad