View Full Version : Changing to wider tires.. need advice


Squidward
09-23-2003, 01:24 PM
Question:

What is the maximum tire size My RX-8 MT's 18" rims can handle before I start running into problems (such as rubbing, etc)..

anyway, if there is anyone out there with knowledge in this area, please elaborate on this... How far can you go in terms of only changing the tire, on a typical wheel...

I'm looking to increase the width of the tire, mainly for visual kicks.. something like 235/40 or 45's would be great...

wakeech
09-23-2003, 05:36 PM
you mean SIDE WALL HEIGHT (or just "height")??

*shrug* measure and see how big you can go.

TybeeRX-8
09-23-2003, 08:58 PM
Take a look at this thread:
http://www.rx8forum.com/showthread.php?s=&threadid=11421

Squidward
09-23-2003, 09:36 PM
Wakeesh, I mean the width of the tire, primarily.

I don't want to replace my rims, just want to add new thicker tires.. How wide can the the the current OEM 18's take?

235 is okay Ithink, how about 265? 300??

syntrix
09-23-2003, 10:28 PM
The stock 18's are 18x8, so a 245/40/18 will fit on there no problem, but it's like a 1% difference on the speedo conversion. Also that size has a LOT more options than the stock 225/45/18.

I just ordered better tires for the stock rims, so I just went through all the research.

mikeb
09-24-2003, 01:37 AM
someone put 275 in the back

Good Duck
09-24-2003, 01:39 AM
syntrix,

Which tires did you finally choose?

wakeech
09-24-2003, 03:50 AM
ah ha... so you did mean width... what really threw me was this:

Originally posted by Squidward
something like 235/40 or 45's would be great...

...which lead me to believe you wanted vertically wider tyres :)

Kev
09-24-2003, 04:43 AM
that's right, vertically wider - for the tardis :D

wakeech
09-24-2003, 12:33 PM
Originally posted by Kev
the tardis :D

coolest sci-fi concept 3vAr...

*whistles BBC Radio Orchestra's Dr.Who theme*

Squidward
09-24-2003, 02:14 PM
I how about Potenza RE040's that are
255/45/18

I looked on the Bridgestone website to find out the allowable minimum rim width is 8 inches.

so it should be okay right???

are there any potential problems here?

Vaillant
09-25-2003, 02:35 PM
This might help you out...you can figure out how much of a change in the overall diameter different tire and wheel sizes could have. This is important in order to keep the speedometer accurate...

http://www.miata.net/garage/tirecalc.html

- Matt

syntrix
09-25-2003, 09:08 PM
Or if accurate speedos' are your requirement AND you want to change the diameter, this might work on the 8:

http://www.blackrobotics.com/

Works on other cars, and I have one on my geared 03 R6