i want to run 17's in front and 18's in the back.
will this affect my launch or quarter mile run in any negative way?
in front i will be using 235/45/17 and in the back 235/40/18.
i think this will be the same height.
just want to know if there will be any negatives to this?

thanks

 

No don't do that we have a 4 wheel drive car. Keep wheel diameter the same.

 

Moving to Wheel Tech.

 

yeah well i wanted to know if the wheel diameter would be the same.
because 17's with 235/45/17 and 18's with 235/40/18 are the same height.
so if the wheel diameter is the same....then there should be no problem right?
also i was told that there was some kind of formula for working this type of thing out...

 

You can try crawling the various tire vendors for exact specs. The thing you will need to match VERY closely will be rotations per mile, you will need that figure to be essentially identical. Different tire brands and models will have different numbers for the same size so be sure to do LOTS of research.

That said, I wouldn't do this. You will probably increase oversteer, upset your front to back ride balance (slightly) and change your front to rear braking balance (slightly). And probably impact a couple of other things too. All those fancy electronics we USA guys don't have, for example. If you don't get your tire sizing just right, you stand a fair chance adding a bunch of wear to (or possibly even blowing) your center diff.

As a counterpoint, I've read that some of the JDM guys are running a wider front wheel and tire to help offset the Evos understeer. A better solution to that would be proper suspension tuning, though.

Good luck!

 

with bigger tires in the rear, you will only increase UNDERSTEERING! And that's what everyone is trying to eliminate on a FWD and AWD car. Some tunners or racer use bigger wheels or tires in FRONT to reduce pushing, just the other way around. When you have a setup like that (big rear wheels and smaller in the front) you are simply telling people do don't know what you are doing and just want to look bling.

 

ok well i got a formula to work out the difference in the amount of revolutions between the 235/45/17 and the 235/40/18.
with the 17's it is 796 and with the 18's it is 794.this seems pretty close.
so what would you suggest.
should i use the 18's up front and the 17's in the back?