I need advice.I have 8.5 inch wide rims and the recommended tyre size is 235 for this width. The problem I have is that the tyres I am getting only come in 225 and 245,not 235! All will fit the rim but which is the best fit? The 225 stretched or the 245 loose for going around a track with??

 

Matt
The correct size is 245-40/18.Plenty of guys are using this size.It's the same circumference as the original 225-45/18.
Hope you Dad got his brakes fixed OK.
Cheers
Len

 

i don't really understand what you mean by 225 stretched or 245 loose. If you fit 225 or 245, it will fit nevertheless on an 8.5in wide rim.

if you want 225, get 225/45. if you want 245, get 245/40. This is of course assuming your rims are 18".

However, having 8.5in wide rim, I would suggest 245/40R18 tyres.

if you want to find out how wide (or narrow) a tyre can fit to the 8.5in, try the rim width calculator on http://www.carbibles.com/tyre_bible_pg2.html and just have a play around with the tyre wide.

 

I think it would depend on what you prefer for track... Straightline grip or Cornering Stability.
245 will give you more rubber on the road for straightline grip.
225 will give you more cornering stability because the sidewalls wont give as much, because they are slightly stretched.

Well thats my view anyway, I could be wrong.

Tire Cam (V8 Supercar)
http://youtube.com/watch?v=s3mrcjKUxtU

 

the tyre should have a range of sizes it can fit and it can vary between manufactures on their recommendation. which is closer to the center of the range of rim widths?

I prefer larger than smaller. I had 235's stretched onto 9" and I didn't like the feel. my reasoning was once the tyre started to roll you were straight onto the side wall where it wasn't gripping.

 

hmmm.. obviously I have no idea what this stretched and loose term are. googling...

 

are stretched and loose even proper terms? lol I got stretched from a term used in drifting fashion. it's more of a look thing for the tyre and rim.

still a tyre width that is smaller than recommended for the size rim you have can be "stretched" on to that rim. the opposite is true that a tyre wider than recommended for the rim size is 'loose' or 'bagging' out from the rim.

 

Similar question here - http://www.rx7club.com/showthread.php?t=127950 They chose the 225s.

225 is as low as the Calculator would allow on an 8.5" rim.

http://www.bigcustomwheels.com/info_specs.jsp

 

Thanks for the help guys. I think I will get the 245's..

 

Good choice. I think 225's are too narrow for 8.5 inch rims.

I've got 235's on the same width.

 

As has been mentioned, it depends on the tyre as different tyres have different "245". BU that being said 245 should be fine on an 8.5. I ran my 245 R888 on an 8.5" rim and they measure 255mm