120/80 vs 130/90 & T63 vs MT21?

Just wanted to see if anyone has switched from running a 120/80 to 130/90 on the rear or a T63 to an MT21. My bike has the standard mods (airbox, pipe, programmer, 48T gear) and stock size (80/100, 120/80) T63s. I rode a friends DRZ400 not long ago and it seemed so much more sure footed off-road. That bike had 90/90, 130/90 MT21s running the same air pressure (18psi). Not knowing how much of the difference is suspension, or CG, or tires I was thinking about putting bigger MT21s on my WR to see what it's like, but I'm concerned that the MT21s or the larger size won't be that noticeable and it will be a $180 failed experiment. I'm also worried that a 130/90 MT21 will be too tall and it will feel like I'm running 43T gears again. Going to 48T was the most noticable improvment I've made and the last thing I want to do is nullify it. Sure, I could go up to 50T, but I only want to do that if it's really worth it to run 130/90 and I don't know if it is. That's why I'm here.

So if anyone has switched between T63s and MT21s or from 120/80 to 130/90 in either model I'd really like to hear your experience, particularly off road. I'm only on a highway for a couple miles each ride and don't need to go over 65 or ride in the rain (much).

I'm running a 130/90 MT-21 and a 12 tooth front sprocket 99% off road. Couldn't be happier. Biggest improvement you can do is to start running lower pressure offroad. 15PSI minimum without a rim lock - put a rim lock in there and take it down to 11 or 12PSI. Unless you're riding hardpack.....

While I've never ran mt21s or t63s on my wrr I tried 120/90 (free used ones) and 100/100 rear tires and prefer the smaller one.

The bike doesnt have alot of power to spin large rear tires, fat rear tires make the front push in turns off road and it sets a bit too high in the rear as well, it smiply works better with a small rear tire.

A drz doesnt have those issues execpt for a fat rear tire making the front push in turns more than a skinny tire, thats true for any bike.

Get the 120/80 either the mt21 or t63 will work good.

Biglake wrote:

Get the 120/80 either the mt21 or t63 will work good.

Thanks for the feedback, that makes a lot of sense. I am running 80/100 and 120/80 t63 now. Rear seems to lock up pretty easy and be a little sketchy offroad. The front seems less sketchy but not as good as it should be. Lots of rocks where I ride so I'm not sure if I can get away with 15psi, but from the feedback so far I'm thinking leave the t63 on the back, go to a 90/90 mt21 on the front, drop down to 15psi on both and make sure to cary an extra tube and spoons for a while.

I would put most of it down to the tyre being a T63. i personally havent found a michelin tyre across any class that i've liked riding on (thats personal preference though), even their road tyres that everyone loves (pilot road 2/3, pilot pure) i've found quite skatey. plus their bitches to fit with their stiff sidewalls.

i would go the MT21's (120 rear) and run 15psi front/13 rear with rimlocks (up 2-3psi depending on terrain). or mt21 rear with XC M/H front.