Thanks for your info ---- the stock offset on a ITR is +50--it is stamped on the inside of one of the spokes next to JJ15x6 and confirmed by my own measurments, I did some number crunching and came up with some interesting facts. Stock wheel with 205's--the rubber is wider by 5mm on each side from the 195's--obvious!! but now facter in an offset of +45 and you find that a 205 is 5mm narrower on the inside and 5mm wider on the outside, again obvious-- all we have done is move the wheel center line by 5mm to the outside. This fits--I ran this last year with no problems. Next we stay with the +45 wheel and put on some 225's and find that we are 10mm wider on both sides--makes sense right! So where does this leave us in comparison to a stock wheel and 195 rubber?
With +45 offset and 225's we are 10mm wider on the inside and 20mm
wider on the outside!
With +38 offset and 225's we are 3mm wider on the inside and 27mm wider on the out side! Thats more than an inch [ 1"= 25.4mm ]
So by the numbers it seems that you stand a better chance of having no rubbing with a 45 offset But! this is theory and in practice ???????
Hence I'm still looking for someone who can say--" I am running 15x7 wheels with an offset of ??? and 225 tires and it fits perfectly"----before I order my new wheels for this seasons autocross and track time.
Please and Thanks.