NEED HELP TO GET GEARING & CHAIN RIGHT!!

I have been riding dirt on and off for many years but just purchased a 2012 WR250R to serve both purposes but mainly street. I have 17" supermoto wheels and tires in the mail and want to get my gearing right before they arive. I want to be able to ride at 75mph without reving super high. 75mph with the stock R 18"/21" wheel setup revs higher than I like and I believe that the 17" wheel will make the bike rev even higher. I have never raced and dont plan to so I have always just ridden bikes with factory sprocket setups and do not know anything about selecting proper sprockets and a matching chain.

If I go up 1 tooth on the front sprocket will it make much difference and will the stock chain still fit? Should I add a tooth to the front and go a little smaller on the back? How do I know what chain to match up with what I choose? I dont race, I do not want to ride wheelies all over the place, I just want a fun machine that I can ride safely on the highway (70-75mph) without burning the motor up. I want this bike to last a long time.

Any suggestions are appreciated.

The stock gearing for the X is one tooth less at the back to compensate the wheel size difference. I ride stock gearing, so can't suggest anything to you, but maybe I can make you reconsider

my bike spends a lot of time doing 70 mph and it's not a problem. maybe if you are used to different bikes, it seems like the engine is revving high, but really for this motor thats normal. and when I say a lot, I mean a lot . even with luggage, I have had it pinned at 70 mph for 900 km straight in one day, with stops just for fuel. bike never complained.

also since it's only a 250, it might have trouble pulling you at that speed at lower revs with taller gearing as it doesn't have enough torque to do so. this motor needs to rev to produce power.


take it on a long highway stint and see if you still feel the need to raise the gearing, sacrificing acceleration and pep. also, I have noticed there is quite a difference between 70 and 75 mph so try to keep it at 70 and see how you like that.


also, you can play around with this http://www.gearingcommander.com/ to see what the theoretical speeds would be

bigg wrote:

The stock gearing for the X is one tooth less at the back to compensate the wheel size difference. I ride stock gearing, so can't suggest anything to you, but maybe I can make you reconsider

my bike spends a lot of time doing 70 mph and it's not a problem. maybe if you are used to different bikes, it seems like the engine is revving high, but really for this motor thats normal. and when I say a lot, I mean a lot . even with luggage, I have had it pinned at 70 mph for 900 km straight in one day, with stops just for fuel. bike never complained.

also since it's only a 250, it might have trouble pulling you at that speed at lower revs with taller gearing as it doesn't have enough torque to do so. this motor needs to rev to produce power.


take it on a long highway stint and see if you still feel the need to raise the gearing, sacrificing acceleration and pep. also, I have noticed there is quite a difference between 70 and 75 mph so try to keep it at 70 and see how you like that.


also, you can play around with this http://www.gearingcommander.com/ to see what the theoretical speeds would be

Thanks for the info. If I put on a 1 tooth less sprocket would I be able to use the stock chain? If you are not sure, does anyone know where/how to determine what chain size I will need?

Check out this thread.

https://wr250rforum.forumotion.com/t5-chains-and-sprockets