I was wondering if the info you gave me was from personal experience or from what others had told you. On the thread I started for "ITR mods for a track day car", you said 225/50/15 would fit on 15x7 wheels with a 38 mm offset. As this is the tire size you and I would both like to run, I would also like to know if it really fits before I order the wheels. When I spoke to Tire Rack, they said a lot of people order just one wheel/tire combo to try out the fit and he said they will accept return if the tire is unsused. Client of course pays shipping both ways. As you and I are both basking in the snow and wanting to run at Mosport, customs clearance is a bit of an issue, but we can wait for the info. I also did a search on a few boards but was unable to find an answer. I also checked out Kosei's Japanese website and they have a new lighter version called a Kosei K-1 Racing TS version, just 4.9 Kg for a 15x7. I also found out that the Buddy Club P1 Racing is the same wheel as the Kosei K-1 currently being sold by Tirerack. Check out the site www.wheelspecs.com and search for wheels from 15x7 min to 15x7 max and less than 14 lbs. Then you can look at available sizes, offsets and weights.

 

It was what other people told me--and the more I asked around the more confused I got. The best info so far is a 45 offset on the 15x7 --but it was
qualified by " you may have roll or cut the lip on the fenders for clearance" and since I am trying to avoid that if possible---hence the thread looking for the definitive answer from some one who has been there. So maybe we will get an answer after this weekend.

 

Ole Yeller...
Here's what I got. The stock wheels are a 50mm offset, as you said. The Mazda Millenia wheels are 15x6 w/ a 50mm offset (I was wrong before). The 50mm was stamped and verified.

The 225's on the Mazda wheels w/o spacers, will rub both on the inner front wheel well (near the trans housing) and on the rear trailing arm. This comes from the previous owner, whom I trust.

With the 5mm spacers in place, I'm creating a 15x6 w/ 45mm offset, which works w/o rubbing.

Regarding the 7-inch width you're looking at, I think it's fine since you're adding 1/2-inch to each side of the wheel, but not affecting the 225 width which is more than the wheel.
The 225's w/ 5mm spacers stand proud of the side of the car, just a little bit. They look good and 'strong'. For this reason, I would not recommend the 38mm offset, which, as you said, add's a lot to outside dimension.

If you do decide to buy, and test fit them as Descartesfool suggested, here's what I'd do. Measure the distance from the hub center to the fender lip. Jack the car and remove the strut. With the car still in the air, mount the wheel/tire, and jack it up into position using your measured ride height. This will allow you to look all around for clearance with the car in the air and the wheel/tire in the correct position. If you leave the strut on, you won't be able to lift your suspension high enough (the suspension will compress some and then lift the car off the stands).

I wasn't able to run the race tires during the autocross, yes it really was that wet, but I really love the new R. I got the fitment info from a test fit I did on Saturday. I'll try to post pic's of the tires soon.

Sorry that I can't give you exactly what you're looking for, but I hope this helps.

 

nw98typer--- thanks for the research, it does seem that +45 is the way to go. One point though-- a test fit as you described does not take into account suspension compression under heavy braking or cornering.
I spoke with the Solo 1 champion in Ontario CA. He runs a 45 offset but cut his fender lips down to nothing--- it seems I will have to do this or stay with the 205's-- [descartesfool take note] He did say that having a camber kit e.g. Skunk2, helps a bit since he has 2.5-3 degrees of neg camber dailed in at the front. This of course tilts the top of the wheel in towards the engine.--As for wet weather, I have had very good results with the Yok AO32R--can't wait to see what the new Soft Compound Yok will be like. Some people up here swear by the Toyo RA-1 at full tread in the wet. I have a post in the SCCA forum on this offset question-may we can get some more info there. Thanks.!!!

 

Good info. I guess I will be getting the 15x7 wheels with a 45 mm offset and hope that the 225/50/15's don't rub too much. I plan to get a Skunk 2 camber kit for the front and an Ingalls camber kit for the rear, with 2-3 degrees neg. camber I think. Could you ask about alignment settings including front and rear toe? There are also light-weight wheels at a good price from Rota (Slipstream) and Team Dynamics (Pro Race). I did not check what offsets were available on these for the ITR. About the Yoko 032R SC (Soft Compound), there did not seem to be any info on the Yoko web site, although they are mentioned in GRM magazine. Do you know any more about them? I am really leaning towards Michelin Sport Cup, even though they are expensive, but Michelin says you dont have to shave or heat treat them, which makes their price more comparable to shaved and heat treated Khumos considering they wear longer in my experience.

 

I did ask about the toe, and they weren't changing it from the stock setting. I have heard (grapevine) that some people run a little toe out in the rear for better rotation.

There aren't any changes to the camber either as the car is DS.

Regarding the tires, I don't have any knowledge. After spending last year on Azenis, it's going to be a learning year on the race tires.

 

My advice is tread lightly in the rain with R compound tires, if you haven't tried it! You will learn the meaning of aquaplaning. Street tires have way more grip in the wet than R compounds, particularly if the R's are worn or cold. On Michelin's web site, they recommend cutting grooves in the Sport Cup tires for the wet.