On AP2, will going to 255/40/17 Rears, and maintianing 215/45/17 Fronts, in any way affect the operation of the ABS system since the rears will ever so slightly be taller? Thanks

 

Probably wont affect ABS

That set up may promote understeer. You will be adding grip to the rear and not the front.

I would upsize both or leave it stock

 

Yes. And it depends on what tires he's talking about. If he's talking about RE050s, then yes. If he's talking about something else, then we should recommend that he not mix tires. The tread widths may not actually be 10mm wider...

 

all fours will be kumho SPTs

 

Check your tread widths and compare to the OEM tread width stagger. If it is less, you may get more oversteer. If it is more, you might get more understeer.

 

Looks like those tires don't have tread width data published. But based on section width, you still won't have as much stagger as OEM tires. So, if anything, you could go wider in the rear or narrower in front to maintain OEM handling balance.

 

yes, for the SPTs, no data available, even from kumho.usa

Since the OEM RE050's Fronts are particularly narrow tread, then they would be likely wider w/ the SPT front of the same size 215/45/17. So since their a bit wider in the front, I thought I'd go a bit wider in the rear w/ SPT 255/40/17.

That's my train of thought to go w/ SPT 215/45/17 Front and 255/40/17 Rear but want to clear up any issues that it may have affecting ABS.

thanks