I have Falken Azenis RT 615 tires as my track tires. Don't ask. 235 40 18 front; 315 30 18 rear. They came with the wheels I bought. That said, my rears are shot but the fronts have a lot of life left in them. I think these tires are just OK on the track.

I don't feel like buying all new tires so was going to put Nitto NT01's on the rear and just run the Falkens on the front. I know this will cause some understeer but trying to determine if this will be a huge problem or just a small one. I have run different tires front/rear on other cars for the track but that was usually to cure understeer/oversteer.

 

I ran MPS2 front and Falken rear on track and street before, with PSM off, no problem. Had this combination on one set of tires (have two sets) for over two years. Your PSM may come in more often if you have it on.

 

I don't use the PASM on track and I don't use these tires on the street. I kind of figure I will encounter more understeer but the Falkens have a lot of life left in them and I just can't toss them out because the rears are shot. I figure I will burn through both sets at the same time and then can match. No biggie here.

 

Same for me... I couldn't toss the perfectly good tires so I mixed them. The RT615 felt somewhat bouncy at 44psi but they felt great after I lowered them to about 36. I did a lot of aggressive driving with them. Good luck.

 

If you're running AWD just make sure the diameter/circumference is very close so you don't trash your front diff. Any other issues are easily addressed with air pressure, driving style, etc.