Retracting my prior "it shouldn't matter" comments. I have not had it happen to me, but obviously people here have. YMMV, but I'd listen to the people that had it happen than theory from someone who didn't...like me

 

Uh, just to be clear and to gather a bit more info:

The issue being discussed would only be an issue when the car is equipped with DSC. With no DSC (or it turned off) you could run any sized tire with absolutely no issue. The tire width is not the issue per se, insofar as the tire width is a parameter in the formula that determines circumference via the aspect ratio and rim diameter.

In saying all that, there must be some threshold (that I earlier dismissed; my apologies) where the difference in tire circumference becomes a problem for the computer. Where that threshold is is unknown.

Kane, do you have DSC?

 

maybe the rx8's ecu isn't as sensitive about wheel diameter as i may have thought.

ben is it possible for you to go in to a snowy empty parking lot and play around a little lock up the brakes spin the rear tires a little bit and see if any warning lights appear. if it goes in to limp mode it could be quite dangerous if you where in traffic and had to slam on the brakes then try to accelerate immediately afterwards

i recall my old miata abs light coming on when i had incorrect tires on it. but dont recall how much they where off.

 

Carbon yeah - I have a GT.... so I gots DSC.

The variance we are talking about is too small I think.... if you were running 305's and 195's you might have an issue.

 

Hey Nate, I actually took some hard turns in the snow and my DSC came on and off as usual....I didn't notice anything weird. I've driven it pretty hard to test the tires, but I haven't noticed any difference....not even in ride comfort....so thank God, so far so good!

 

As I've said, I think you'll be fine.

You'll only be seeing issues if the tire diameter is much different.. like 35's with 55's..

 

well it seems the 8's not as sensitive as i thought. glad its all working out for you ben.

 

Thanks for all your helps dudes!

 

Yeah, I was inkerrect. Great it worked out and will keep this in mind.

 

I had that 'limp' mode once, freaked me out! couldn't get one summer tire off (lock nut) had to drive home from my buddies house across the 401 and all of a sudden, no power, no throttle and I was slowing down with ppl on my ***. I didn't know wtf was going on. Got down to about 70km and it kicked back in with all my DCS lights on. Drove slowly home, got the tire changed and all good from there.

 

You absolutely should not be mixing brands front to back (did the shop manage to hook you up with the same Pirelli snow tires?). Heck even within the Pirelli SnowSport line there are 5-6 different tread patterns that are nothing alike. You can take a chance and limp on these for a couple more weeks, but make sure you use 4 identical brand/model tires for next winter.

 

Well, since I bought two used (but fairly good tread) 245's for rear tires, they came as Pirelli 210's. The back two (225's) got swapped to the front as they have pretty good tread and they are Pirelly 240's.