Is running a 9' rim with 18's gonna hurt me?

[300ex_#387]

I was just wondering what is the pros and cons of running an 18' tire with a 9' rim?

[Rico]

Depends on the rim.

[Hondacrf15]

Usually running a 18" tire on the 9" rim.... the sidewall of the tire has to be made very stiff to make up the 1" difference. This translates into a very harsh ride from the rear tire and poor cornering flex from the rear tire. Better to go 18" tire on 8" rim. This is for MX of course.

[2000_mx_banshee]

Here's my 2 cents...

I prefer an 18" tire on a 9" inch rim because there is less roll or flex in the tire when cornering. I have tested and there is a noticeable difference with an 8" as opposed to a 9", when talking body roll. On the 9" rim there is less tire sidewall and therefore feels stiffer, making for less flex under hard cornering. Less body roll translates to improved cornering speed and less fatigue (less body english to keep it on all fours)

Now, on the other hand, an 8" rim (which is used by most pro's, but not all) has a touch more flex for generally a little plusher ride. The advantage of the 8" is that there is more sidewall and a greater distance the tire has to compress before wrecking (read flattening) the rim. Meaning that when landing big air, and I mean big enough to bottom the suspension (which your suspension should be tuned to do on only the biggest jumps) you are less likely to damage a rim.

All that said, there is something else to consider also. This is that we are not all professionals that get free parts. If you buy an 8" rim you can ONLY mount an 18" tire. Where I ride there are a few tracks with loose soil and some sand. On these tracks I run ITP's 19" MXR4 (19X10-9) tire, which is an awsome tire only available for a 9" rim. Farr ran them at last years GNC opener at Glen Helen to take a 1-1 finsh, and I run them a specific tracks on my 9" rims.

Hope this helps. Best bet for you is to borrow an 18" tire on an 8" rim and see if you like the ride better. I did, and preferred the 9".

[Franky G]

I like th 9" rims better then the 8" to

[NacsMXer]

I agree with you guys. I run a set of Hiper 9x9's with my Kenda Klaws, so I don't have to worry about busting rims on landings and such. You get the best of both worlds IMO running a 9" rim.

[300ex_#387]

Alright thanks for the info. I guess I will try the 9' rim.

[MXRACER86]

I had tried both and I gotta say that the 9inch is the way too go!

[300ex_#387]

So do you think it rides pretty rough with the 9's? Im only going to be doing MX with them so it cant be that bad right?

[MXRACER86]

Originally posted by 300ex_#387
So do you think it rides pretty rough with the 9's? Im only going to be doing MX with them so it cant be that bad right?

I have owned both and I don't think it rides any rougher!!! I think 9inch rims are the way too go!