Wandering/Tramlining under braking, is this normal?
I am still fairly new to tracking. I just put on some RE71RS’ on my car.
Right away I noticed a nice step up in grip compared to the stock BMW spec PS4S’s. But under heavy braking I am now feeling a little unsteady behaviour like the car is moving a bit side to side, sometimes only in the front sometimes in the rear.
My M240 xdrive is mostly stock (just stainless steel brake lines and CastroL SRF race brake fluid). It is just over a year old (2025).
Stock tires were 245/35r19 front and 255/35r19 rear. My new track tires are 265/35r19 square.
For reference I drove both tires same track same day same overall weather, and the PS4S feel fine under braking but the RE71RS feels a little more jittery, though it has a lot more bite.
Currently on factory stock alignment that was measured roughly at -1 camber, 7.2 caster, 0.17 toe in left, and 0.21 toe in right. Rear is about -1.5 camber and 0.1 toe in each side.
Is this something that just comes with better rubber or likely something with my setup I can adjust? I was told by the alignment shop 0.38 total toe in at the front is a lot and if we went to something like 0.1 total toe in it would make the car much more alive, but I am concerned that would make the straight line braking even more jittery and unstable?