XR650R gearing? 42 or 40 tooth rear?

ive already changed gearing to 15-45 but i want it taller for supermoto/road only use.

Changing to 15-45 helped quite a bit but didnt really expand top speed?:thumbsup:

Anybody use 15-42 or 15-40 and how is it? i am willing to loose a little low end because atm its at 7500 RPM's at 85-90. I just wanta bring the revs down.

ive already changed gearing to 15-45 but i want it taller for supermoto/road only use.

Changing to 15-45 helped quite a bit but didnt really expand top speed?:thumbsup:

Anybody use 15-42 or 15-40 and how is it? i am willing to loose a little low end because atm its at 7500 RPM's at 85-90. I just wanta bring the revs down.

Your bike can handle a 41 no problem because of your smaller 17in rims, I don't have 17s on mine and I run 15 45 my buddy has 17s and runs 15 41 and are bikes are neck and neck right up to top speed 15 45 is to low for you.

Running 14-45 on a few bikes. The XR600 102gps,CR500 92Gps, XRL I haven't pushed yet but expect around 105. All running 18's rears for dirt with pirelli mt-21's except the CR witha dunlop. My buddies uncorked 650R is about the same top speed as the CR, but quicker than my 600R. The 650L is about dead even on the road with the 650R. The 600R is slower, but top speed is better. The CR walks the 650R but not grossly. Supermoto I would run maybe a 40 or 42. You can calculate the top speed with tire size, gear ratio, and sprockets sizes. Of course you can't go to small like at the salt flats or you will need a push to start, But the top speed would be unbeatable by your buddies!!!!

Of course you can't go to small like at the salt flats or you will need a push to start, But the top speed would be unbeatable by your buddies!!!!

I already have a dead spot in 1st gear, i really cant go under 7-8 MPH because it bucks like its gona die. I quess that will be even worse after dropping 5 teeth in the rear but im gona go for it anyway, because i dont do much slow stuff.

ive never heard of anyone going under a 40 rear...would i just be burning up the clutch trying to start off if i was to go under 40 tooth?

I have 15/39 and no issue's with my clutch,been running it for a while now,just street use no actual track/supermoto.

15/42 w 17" street tires. No issues; >100mph top speed.

ok i quess im going with a 40 tooth, we'll see how it works out.

Have you tested it yet?

Have you tested it yet?

i orderd it friday, should have to next week, but i dont think im gona take the time to put in on until i have to change my rear tire.

Okey! :thumbsup:

Tell the result here. I'm a bit interesting in changeing my 15/45 to 15/40 just as you do, so it would be nice to hear the result =)

Where did you find the 40T rear? Be sure and keep an eye on the chain slider--with mine at 15/42 the chain is slowly but surely cutting it apart.

With regards to the low end dead spot, I switch to a 14T front if I'm going to stunt or ride offroad; it's nice to have options.

According to the XR650R Yahoo group, the Eurospec Rs have 15/41 gearing stock. Seems tall, but they're street-legal there.

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