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View Full Version : largest tire size on stock rims


wraith02
11-11-2008, 06:36 AM
I've been searching the forums for hours on end and I can't seem to find a solid answer on what would be the maximum tire size that will fit on the stock rim without rubbing. the local dealers tell me 225/40/18 is the highest i can go. any help is appreciated
strytnyne
11-11-2008, 07:35 AM
225/40/18.. is safe, but 235 is pushing it though some people have done it, look few threads down, about the 235 azenis on stock rim
spdjnke
11-11-2008, 07:35 PM
For safety purpose I would NOT recommend you running 235's on stock 7.5 wheels. cuz there is a chance that you will be premature BEAD failure due to the side wall flex on the tire. Stick with 225 and your safe!! otherwise go with new rims at 8 or 8.5 then you can safely run 235's
def_one
11-11-2008, 08:26 PM
Our stockers are 18x7 arent they? I thought they were 7.5 too but when I put on my RX8s they were an inch wider.
Kain
11-11-2008, 08:55 PM
Stockers are 18"x7".
fragchild
11-11-2008, 11:20 PM
I just put 225/40/18's Yokohama s. drives on. When i was chatting with the dude I asked about 235's he said I'd be pushing it and he said there's no way his shop would do it.
spdjnke
11-11-2008, 11:21 PM
Oh man if they are 7 that's EVEN worse!!
MS3Zoom24
11-12-2008, 12:50 AM
Y are you guys changing from 215/45 to 225/40 instead of 225/45? Is there clearance isssues?
Yoo Shin
11-12-2008, 01:17 AM
Y are you guys changing from 215/45 to 225/40 instead of 225/45? Is there clearance isssues?

Yes, some have had clearance issues, especially when going wider on the wheel and lower on the offset. Also the choices in 225/40 are more plentiful and reasonably priced then the 225/45s and especially a 215/45 (if you can actually find them).

I'm finding myself shoping for some decent 225/40s to hold me over for another 3-4 months before I upgrade wheel size and tire.
silversurfer513
11-12-2008, 12:43 PM
I just put on a set of 225/40 ContiExtreme Contacts with no issues. Crossing my fingers that they will be good enough AS for the winter here in Cincy.
pdqgp
11-12-2008, 02:51 PM
I just put on a set of 225/40 ContiExtreme Contacts with no issues. Crossing my fingers that they will be good enough AS for the winter here in Cincy.

Any balancing issues with the ContiExtremes? I know them to be a touchy tire for balancing. I tried them for a week or so on a previous car and the did great in rain, but I never got them to balance smooth.
silversurfer513
11-12-2008, 03:38 PM
Any balancing issues with the ContiExtremes? I know them to be a touchy tire for balancing. I tried them for a week or so on a previous car and the did great in rain, but I never got them to balance smooth.

I seem to get a slight vibration when they are cold at start up but goes away after a few miles. They were installed and balanced by one the best tire guys here locally so Im not sure how much better we can get it. Good info though, assures me I wasnt crazy!
08.5MS3
11-12-2008, 06:47 PM
Y are you guys changing from 215/45 to 225/40 instead of 225/45? Is there clearance isssues?

And the fact that the speedo will be off.
spdjnke
11-13-2008, 11:23 PM
Y are you guys changing from 215/45 to 225/40 instead of 225/45? Is there clearance isssues?

With a Aspect ratio of 45 you are asking for rubbin in the rear for sure, most of the time if you want to increase the width of a tire you HAVE to drop the aspect ratio down to compensate for the larger width.

Ie, 215/45 to 225 you have to drop the aspect ratio by 5mm, that's why if you check most places will always be 225/40 just so that you don't get rubbing on the fenders, but again that's totally your choice.
def_one
11-14-2008, 04:00 PM
225/45-18 shouldnt be a problem. Thats the stock RX-8 size and people run those on the MS3 all day long without rubbing.

Aspect ratio is in % just a heads up.

So a 225/40-18 is actually a smaller outside diameter than the stockers, will cause the speedo to read fast. The closest match-up would be a 235/40-18, but like everyone has said, would not be recommended on the stock wheels.
MS3Zoom24
11-14-2008, 05:12 PM
225/45-18 shouldnt be a problem. Thats the stock RX-8 size and people run those on the MS3 all day long without rubbing.

Aspect ratio is in % just a heads up.

So a 225/40-18 is actually a smaller outside diameter than the stockers, will cause the speedo to read fast. The closest match-up would be a 235/40-18, but like everyone has said, would not be recommended on the stock wheels.

would you need to get a wider rim? so 7.5 or 8?
def_one
11-17-2008, 03:39 PM
would you need to get a wider rim? so 7.5 or 8?

Yep, exactly. 8" would be perfect for a 235.
JaySmalls
11-20-2008, 07:45 PM
Got a great deal on some Blizzaks sized 225/45 for the stock rim. Am I safe with this set-up or is it a stretch?

Thanks in advance for the good advice!
def_one
11-20-2008, 08:35 PM
No that size is fine Jay, I would say a 205/45 would be better for snow.
JaySmalls
11-20-2008, 09:05 PM
Yeah I know it would be a little better but I had a 03 20th anniversary edition GTI and ran pilot sport AS on 18 inch wheels and that thing could go thru anything. Would drive 50 miles to work in 4 inches of snow!!!

So I have confidence in a wide tire in the snow especially a blizzak thats made for it. Hopefully some more ppl will offer some advice and first hand experience.