I have the exact same tire combo (in 20's) & my car can sit for a week at a time, it's fair weather only, and never feel shimmy or shake, I do keep the PSI at 33-35 all around.
And the 555r is way better traction than stock F1's to me. With only the mods in my sig, which are pretty mild for the gt500 community, the F1's I use for trackdays go up in smoke with any strong throttle, 1st, 2nd, 3rd, and I've had to be more gentle even going into 4th, as I smoked them & unsettled the car (and me) at 140 on a straight. The 555rs still will spin up on throttle alone in 1st & 2nd no matter how I heat them, but 3rd not on throttle alone but still need to be careful on how hard to shift into 3rd, and 4th is solid. So big improvement IMO, but anything less than a slick has difficulty harnessing the power these cars put out with even mild mods.
And the 555r is way better traction than stock F1's to me. With only the mods in my sig, which are pretty mild for the gt500 community, the F1's I use for trackdays go up in smoke with any strong throttle, 1st, 2nd, 3rd, and I've had to be more gentle even going into 4th, as I smoked them & unsettled the car (and me) at 140 on a straight. The 555rs still will spin up on throttle alone in 1st & 2nd no matter how I heat them, but 3rd not on throttle alone but still need to be careful on how hard to shift into 3rd, and 4th is solid. So big improvement IMO, but anything less than a slick has difficulty harnessing the power these cars put out with even mild mods.
