I’m looking for technical help or recommendations on:
I picked up my '07 Icon a couple of months ago with the idea to run it as a track day car. It has Tein coilovers (not 100% sure which ones) and has, as the advert stated ‘fast road and track geo’.
When driving the car follows the ruts of the road, a lot, which I expect is down to the geo as my previous track focussed car did this. However, what’s odd is that under about a 50% throttle, when you lift off it feels as though the car twists. It’s really hard to explain, but it’s what I would typically describe as yaw.
I’ve never had this in a car before, but I think this is the first RWD car I’ve had with a diff, is this simply a result of the diff doing its thing, or is there something else that could be at play?
In terms of tyres, they are all matching Bridgestone, but they are 215/45, which isn’t standard from what I understand.
Not saying the Bridgestones are completely useless, Mazda fit them from new (not sure what goes on new cars now)
I guess they are ok when new but there are plenty of threads on here about tyres (other brands) and Bridgestones. Members favourites etc, Bridgestone doesn’t figure highly as a go to tyre, I’ll just leave it there.
I’d try out your other sets first, settle on what you think is right for the car and driving conditions (track/fast road) then seek advice for an alignment check for such use.
I think you’ll find the Bridgestones won’t be at the top of any of the members list that track their cars.
Btw I’ve had them on a car, couldn’t wait to get them changed.
first of check tyre pressures. I had a very weird handling behaviour in my NC and I couldn’t figure out why. But that went away when I checked and adjusted my tyre pressures to 29 psi.
Check that the rear pair are identical. Production date. tread depth and even country of manufacture matters. There was a case a while ago where an LSD was destroyed due to mismatched rears. This was on a new car. One tyre had obviously been damaged before it reached the dealer. They had replaced it with a matching Bridgestone but a UK produced tyre, the originals being Japanese manufacture. Very slight tread pattern differences and different compounds.
Quite frankly what you describe could be down to so many different things both in isolation and/or in combination. Within whatever budget you have you should work through from easy pickings (such as having matching tyres) to what the geo has actually been set (btw, fastroad/track settings means diddly squat). And you don’t get tramlining just because you have track geo setings!! And then there’s bushes and shockers, and maybe even a sticking brake caliper (ie causing the car to pull to one side).