How Much of a change?

Joined
Feb 16, 2001
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#1
Hello all,
I want to change my Rear Sprocket on my 99 TT-R250.
I want it to have more low end grunt.....
Since I ride mostly trails I'm not too worried about losing topend Speed....
If my thinking is Right I would want to increase the size of the Rear spoocket.....
What would be a good amount to increase..Would 3 teeth be too much ... I basically would like the bike to have more low end "Snap"
to help lift the front abit.
I had seen a thread about sprockets a couple of weeks ago, but I can't seem to find it.
Thanks for any info and Suggestions,
J
 

MikeT

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Jan 17, 2001
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#2
3 is a lot. I'd go with two. If you want more than that, leave the rear sprocket the size it is and thak 1 tooth off the front.
 
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Apr 2, 2001
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#3
Go 2 teeth bigger on a the rear or 1 smaller on the front. That is a big difference. On my old RM i did that(went to a 52 on the back), and i changed the front to a 12. Now that bike was low geared for trails. With my CR i'm running 13/51 and it's great for trails/harescrambles, plus i still got some top-end speed. :)
 
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May 16, 2001
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#4
1 tooth down on the front = 3 tooth up on the rear.
Foir every 1 tooth down on front/3 teeth up on rear you lose 5MPH top speed.
 
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#5
As a rule of thumb that’s sort of close, sit down with a calculator & work it out.

52/12 = 4.33
55/13 = 4.23 so you can try it first on paper to see what ratio you are changing.

JT have a neat chart I keep in my tool box.

Warning too small on the front will wear chains quick, too big on the back will rub chain against chainguides & make chain pos too short. I’d give it 3 on the back as a start.