busterdawg22

iTrader: (5)

I'm looking for some 235/45 for 18x8.5" wheels. No one around me sells these tires and I'm having trouble finding them online. Any recommendations for a brand and where to get them? I would be using them mainly for just cruising/driving, sometimes a race or two. I want good tires, but not overpriced. like maybe the kuhmo Ecsta Supra 712's or the 711's. Need suggestions! Thanks.

Axel

iTrader: (3)

That's not a common size. You'd have way more choices with 235/40/18 instead (or 235/50/18, less choices than 40 but way more than 45).
Also, do you want All-Season or Summer only?
And finally, the Kumho Ecsta Supra 712 don't come in 235/45/18, only 235/40/18 or 245/40/18 or 225/40/18 (all 3 fit 8.5 wheels) and the 711 don't come in 18 inch size.

JUDE

iTrader: (7)

Did you try www.tirerack.com ?

wope

iTrader: (1)

235/45/18 will fit a maxima?

busterdawg22

iTrader: (5)

OK, here's the size of the tires that were on the rims before: 215/40/18. I was told by my friend who knows a lot about cars to never have the size of the wheel and tire combined bigger than the size of the stock wheel and tire. Now here is the big question: If all the tire sizes you mentioned will fit my rim and so will the tire size I mentioned, which is the best one to use?

Axel

iTrader: (3)

It's not a question of bigger or smaller, it's a question of keeping the ratio the same.
Go check out this site http://www.miata.net/garage/tirecalc.html
to calculate all the different sizes.
For example, if you go from 215/40/18 to 235/40/18, you will have a 2.5% difference on the slow side. Therefore, your speedometer will be 2.5% too slow so when you're speedometer reads 60 mph you'll actually be travelling at 61.5 mph. You typically want no more than 2% difference on either end (too fast or too slow) so 2.5% isn't great but it's acceptable. A 235/45/18 tire would give you a 6.3% difference (of being too slow) which is a big no no. 225/40/18 would be 1.3% too slow so within the 2% but now you're only going up one size (from 215 to 225). I'd go with the 235/40/18 if I were you. Play around with that tire size calculator and you'll get a good idea of how it all works. Once you like a size, go check tirerack to see if it's a common size (you can do a search by tire size and see if very few or many tires are found from the search. If many are found, then it's a common size. Then choose one of the tires and go check out the specs & sizes to verify they fit an 8.5 inch wheel. (There's always a range with an ideal like 7.5 inch to 9 inch with 8.5 inch ideal for example.) Last I checked, the 235/40/18 had 8.5 inches as ideal.
I hope this makes sense Good luck!

busterdawg22

iTrader: (5)

thank you so much, that helped me out more than anyone else did. Thank you very much!
- David

busterdawg22

iTrader: (5)

I have one last question: If the rims actually weren't 18x8.5" but in fact 18x8 inches, would 235/40/18 still work?

Axel

iTrader: (3)

If you look at the wheel range requirements for a 235/40/18 tire, 8 inches is fine. The general range for that tire size is 8" to 9.5" so 8 inches is within that range. You still need to check with the specific tire to be on the safe side because this wheel range is applicable to most 235/40/18 but not necessarily all of them.
When you've finally decided on a tire you like, before buying it, check the specs. Any decent tire selling site will have a "Rim Width Range". If the specific tire you choose is within that range (as it should be for most tires of that size) then great. However, if it isn't (for example, if that specific tire you end up choosing says 8.5"-9.5" instead of 8"-9.5", don't buy it as you only have 8" wheels.)
Makes sense?