[GregoryG]

I have a square setup with MPSS 245/35R18 and just blew 2 tires. The remaining 2 have around 5.5/32 of tread left. I figured the 'best' replacement would be new MPS4S because the 2 model tires are so similar. I've been wanting to move to a stickier tire for spirited street and occasional HPDE (it's my daily driver also), so can I safely move to a pair of new Federal 595 RS-RR now, and replace the remaining MPSS with another pair of Federals when it's time?

I figure the new Federals would go in the rear for now. Any advice/suggestions would be appreciated, thanks.

[overcoil]

there is the slim chance you could set up some harmonic weirdness from the different tread pattens at some particular speed.
and at speed the different tires could be a handling issue, but at legal road speeds it's doable.

[ralawren]

Originally Posted by ScottSinger

there is the slim chance you could set up some harmonic weirdness from the different tread pattens at some particular speed.
and at speed the different tires could be a handling issue, but at legal road speeds it's doable.

The adhesion should be close enough not to be an issue. I ran mixed tires front and back at a HPDE without any issues. Actually RE050 rfts on front and MPSS on back.

You could buy used tires so the tread depth is similar. EBAY has used MPSS some times. They normally have been patched but work fine.