I have been running F1 GS-D3 tires 245/40/18 front and 245/45/18 rear on my '04 Coupe 6MT for the past ~25,000 miles. While the tires performance has been incredible, the 245 series front tire has caused the car to tramline (darting and following imperfections in the road, ruts, patches, depressions, etc.) very badly, only getting worse as they have worn, and especially bad in the cold. See the tirerack tech article on this http://www.tirerack.com/tires/tirete...jsp?techid=47&
The rear does not appear to be affected (however it is the OEM width and sidewall) and I have had the alignment checked multiple times by multiple shops and all have checked out correct.
I have multiple friends running these tires on various types of sports cars and no one has experienced this. So, I'm getting pretty desperate to figure it out because they are due to be replaced and I loved them otherwise.

So I'm trying to narrow down the reason. On OEM 18" wheels (or same width rim) has anyone run this EXACT tire and size and had this problem. If so, how did you fix it? Or, have you run this same width and sidewall tire but DIFFERENT type and had this problem?

I believe it either comes from
1) the extra grip causing compliance in the steering and suspension and possibly the bushings need to be replaced, or
2) the OEM alignment camber setting with this wider width causes the tire patch center of pressure to have moved causing a steering torque from scrub radius, etc. or,
3) the plus size fitment of this series tire on the OEM rim width causes it due to the tire construction characteristics, or
4) the V groove tread pattern actually catches imperfections in the road and deflects off of it causing a steering input (I doubt this one as it seems to be sensitive to camber changes and depressions in the road with no "imperfections") or,
5) did I just get a bum set?

Any help would be great as I would love to buy these tires again and hope that bushings or a camber change can fix it. Thanks in advance!

 

I think it's probably because you're not running a staggered width set-up, which is what the car had stock

 

I don't think that's it. The rear suspension doesn't know what the front suspension/steering geometry is and the rear is still as planted as it ever was. Many, many people have put all kinds of different setups on and usually stagger problems come from the VDC if you don't keep the rolling radius similar to that of the stock setup. The 40 series tire with 245 width keeps it very close and I've never had a VDC problem. Going away from the stagger makes a much more neutral G35 at the limit, which I don't plan to go away from. Instead I would like to dial in something else, maybe wider rims, maybe rims with a slightly different offset. Where are the autocross and road racers out there that have gone through all the setups?

 

i've got goodyear eagle f1 gs-d3's on my oem 18 inch rims. i've got 245/40 on the front just like you and i don't have this problem at all. but i've got 255/45 on the rears which is slightly wider and slightly taller than stock. but not enough to mess with the vdc, in fact the vdc comes on far less than it did before (on oem 17's with stock tires). it almost never comes on actually. i know 265/40 on the rear would have kept the diameter the same as stock but people didn't recommend going that wide on stock rims.... but others said it would have been fine...

mine are still fairly new but they drive perfectly straight. I don't squeal through corners or anything though, i'm not sure if you abused your tires but maybe your tires didn't wear evenly?

also, check to see where yours were made. all 4 of mine were made in germany. Most GS-D3's were made in USA or Germany, but I heard from certain people that they got some made in China and they were horrible compared to the normal ones.

my friend has GS-D3's (more worn than mine) on his 300ZX twin turbo, they are 245 on the fronts and they drive perfectly straight.

 

Nabil, thanks for your reply. I also had no trouble with mine at all when they were new, which was also while temps were warm. I'll be interested to see how yours end up over time as they wear, I only have maybe 3-4/32s left. Do you live where it gets cold? I know they don't recommend running these tires below 45 degrees but I have and it gets noticeably worse and according to that tirerack article both of these factors are expected to make it worse.
Also, I see you mentioned having 17" OEM rims at one point, did your car come with it, or more importantly, is there any difference in suspension geometry between the 6MT Brembo performance coupe and the standard 17" coupe? I kind of doubt it.

I beginning to think that others with this package that haven't reported a problem either, never drive on crappy roads, replace their tires before they wear out, don't drive them in the cold, or are just used to tramlining from grippy setups.

All my tires say they were made in Germany, and I don't "abuse" my tires but I do drive the car as it was intended often near the limits on empty two lane roads. I've experimented with numerous tire pressures but these tires have actually worn way more evenly than the stock 225/45/18 Pilot Sports, but they were comparatively narrow and were constantly being over worked.

As for the 300ZX, its all in the suspension geometry and component compliance that matters. Its very difficult to compare things like this between two different cars.

 

all G35 coupes that came with 17s and 18s have the same suspension. the 6MT's with the 19's (starting with 05) had upgraded suspensions.

I drive on a mix of nice and crappy roads... when I'm in the city the roads are pretty bad but in the suburbs they are smooth. the weather is variable here too, it gets hot but it can get to freezing temps during the winter.

 

Cool. When driving relatively slowly on crappy roads, like maybe around the city I never really notice and on great highways that are smooth with little crown to them there is no problem. Tramlining is a weird thing as to when and where it does it, and doesn't do it. I'm hoping someone out there has played with their wheel offsets to change their scrub radius and/or gone to a wider wheel while keeping a 245/40/18 tire, or gone to stiffer suspension bushings to fix it.