I have a 85 ATC250R and I was thinking of changing the sprocket ratios because it pulls so good it feels like it is geared to low at stock, which is 13 front, 39 rear,. What are other sprocket ratios are people running and how well does it work ?

 

I RUN A 13 39 ON MY 85 ATC 250R WHICH IS STOCK GEARING.I HAVE A SET OF 22/11/8 TIRES THAT I RUN ON IT THOUGH.STOCK SHOULD BE 20/10/9 WHICH WOULD GIVE IT MORE TAKE OFF AND LESS TOP SPEED.IF I PUT MY 18/11/8 TIRES ON IT WILL JUST ABOUT THROW ME OFF THE BACK. IF YOU WANT MORE TOP SPEED, GO TO A BIGGER FRONT SPROCKET.

 

on my 85atc i run 12/39 with 21/12/10 tires i have run up to a 14 on the front but was runnin lower profile tires

 

I have been running stock 13/39 . I was thinking of running a 14/38 . I run either stock wheels or some itp blackwater 20's , which are great because they dont spin like the stock wheels. Maybe I better leave it at stock, I might get on a hill and find out too late that I geared it to low and wont make it up.

 

If you plan on running 20 inch tires, put a 14 tooth on the front. You will like it.