4.00-18 VS 120/90 -18 Metzeller

[mrclubike]

Hello all
I am getting a new tire for the back of my R65
Is switching from a  120/90 to a 4.00  going lower my overall gearing.
   I need to get as much speed out of  4200rpm  that I can get .
I could not find any specs on outside Dia on the Metzeler site
If someone has a 400-18 mounted  could you measure the outside dia or the radius for me  (from ground to center of rear axle)
Thanks for the help

[mrclubike]

I did find a size chart on Avon tires and it less than 1% difference in a 400 and a 120/90
not enough to worry about  

[Barry]

Here is something I put together a while back for different tires.  Let me know if you have some new info and I'll add it.

[mrclubike]

                                                                wide    tall  
Avon Roadrider AM26 (rear)      4.00-18       116        671        

Avon  Roadrider AM26 (rear)      120/90-18       129    675        

[Barry]

Thanks

I'll update the table