Originally Posted by Ed@Ford
I'd suggest going to Continental or other sources to get dimensions of the tires of interest and measure the CRF tire for comparison. Since the CRF tire is an 80 profile, it's going to be fairly short...sadly the 120/90 may be tall by about an inch and wider. That inch can throw off your gearing...even if you are using a 13T C/S sprocket instead of the stock 14T. My opinion is too big of a rear tire just bogs little engines like the CRF
Thanks for the warning. That's bad news. After speaking yesterday, i looked at one catalog (the only SA supplier i could think of that had a list online - Michelin, Pirelli...two others i can't remember) and... 120 seems quite non-standard. They were all 130, 140, and the profiles were all 90. Then if you factor in the interest in more offroad type or more onroad type, seems like it's going to be a problem - involving a compromise.
Yes, bigger tire with an engine like this...nah, i'd rather go for a 110, if that's what's available. It might look a bit skinny - the OEM one does already - but it would probably work better. And that means the speedo, too...i can see myself buying that expensive "speedo healer" thing eventually.
What's bothering me, though, is that the front tire seems really wrong on the road - around 100km/h / 65mph, it feels really skittery. Quite unusual for me. Limited experience, but my KDX full knobbies are so stable on the road, they grip amazingly, and when they are getting near the limit, i can feel it. So i must see what i can get that is more suitable for the road.