I have ABS on my i30 and need new tires. I need 2 new tires now, 2 more in a few months, and money is tight. I have 225/50/16 tires now (24.8" diameter), and want to go to a 215/55/16 for my next set. Their diameter is 25.3"- which is a little larger.

Will doing 2 of the tires now mess up the ABS on the car?

I will be keeping tires of the same size on the same axle, of course.

 

if it helps at all, I've got 235/45/17 tires on my Q45 rims, which have a little bigger diameter than stock if I remember correctly. I also have a big brake kit, and the ABS still works fine.

 

I know that I can go bigger or smaller than stock, but I am worried abotu the different sizes on opposite ends- at the same time.

 

I believe the ABS system controls all four brakes independantly, so it should still be okay.

 

Sounds correct- there are 4 "out" and 4 "return" lines on the resevior.

Can anyone substantiate this assertion?

 

That small margin of error will not cause your ABS system to report a fault.