wheel & tire sizing

[luis]

So, the 15x9 +36 6ULs run a 225/45 15. Is there any disadvantage/advantage to running this width wheel versus 15x8 +20 with the same tire? The position of the outer facing lip is a mere 3mm. The recommended width for those tires are 7"-8.5" Would there be any concerns with suspension clearance? Please enlighten me.

[trickyrix]

I'm running a 15x8 6UL and a 225/45 with almost no problems. I'm still running fender liners and I've only had to bend in the liner mounting tabs on the front. At the rear, I had a tire snag the inner fender lip at the track, but I was able to pry it back in with a cheater bar - no fuss, no muss.

However, if you haven't already found out, the selection of 225/45 tires has dwindled down to about 1 street tire - the Hankook RS3. From what I understand, it's a great tire, but with its 140 treadwear rating, I'm not sure how long it would last as a DD tire. So, as my old RS2s wear out, I'm debating on whether I should pop for a set of RS3s or downsize to a 205/50 Dunlop Star Spec.

[Nails]

RS3 has more grip but probably about 4 months less life.

[juxt3r]

So, the 15x9 +36 6ULs run a 225/45 15. Is there any disadvantage/advantage to running this width wheel versus 15x8 +20 with the same tire?

Fitment aside, you won't be maximizing the benefits of a 225 tire on an 8" wheel. Put another way, the tires' shoulders won't be squared off like they would be on 9" wheels.

Can't speak to fitment, as I've never run an 8" wheel with a +20 offset on an NB (assuming the car in your avatar is the critter in question, of course).

[luis]

Isn't a 15x9 slightly stretched w/ 225? I probably should have specified that I won't be using these as DD tires. I plan on buying another set of wheels for this tire setup. So you're saying trickyrix's setup isn't square?

[trickyrix]

225s are pretty square on my rims but I know the track guys like their 225s on 9 inchers. Either way you should be good.

I'm trying to remember what offset my 6ULs are... 20mm doesn't sound right but it's been a while since I ordered 'em...

[cleave]

From the 15x9 source himself: http://forum.miata.net/vb/showthread.php?t=266393

[juxt3r]

Tricky, your wheels are GenII 6ULs, so +36.

...and yeah, the 225-45 tires work just fine on the 8" wheels. Ran that for a while, personally and loved 'em. The 9" wheels just fit the 225s a little better is all.