Getting smaller rear sprocket, a question

3 replies to this topic
  • fastenuf4u

Posted May 12, 2006 - 05:25 AM


I am going from a 49 tooth rear sprocket to a 47 tooth and wondered if it would be better to shorten the chain or just push the axle back to make up for the difference? I have always heard shortening the wheelbase can help the bike turn better but I wanted to see if anyone on here had some real world experience with either of these options.

The bike by the way is an 03 YZ450F with 4 oz. Dr. D flywheel weight and complete Dr. D exhaust. I feel on the track I mainly ride that 2nd doesn't give me enough speed to clear some jumps but 3rd lugs a bit and I have to downshift in the air to get ready to get back on the gas. I would rather just have a longer 2nd gear which is why I am going down rather than up! Thanks.

  • FZ1426

Posted May 12, 2006 - 06:35 AM


You have come across one of the major dilemmas of moto life. Yes, shortening the wheelbase won't hurt turning, and will improve traction in some conditions. Lengthening it will improve high speed stability. If you're on a track in second most of the time, shorter (shorter chain) is probably the way to go. But then you lose the flexibility of going back to 49 (without another chain). Moving the rear wheel also changes the leverage and action of the shock, which may require slight comp and/or rebound adjustments in certain cases. Sag/preload changes slightly also. All of this is why sometimes changing the front sprocket (one tooth) is a better option. It's all about compromises. Changing the front will have less effect on wheelbase and suspension. In either case now you have to make sure 1st doesn't get to high. There's no easy answer...have fun. :ride:

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  • grayracer513

Posted May 12, 2006 - 07:10 AM


I run mine with a 15/49 (vs. 14/48 stock), which is the same as a 14/46. It's a little high for some tracks, and I need to use first some, but all the gears are really long legged, and the wide torque curve makes it easy to use one or two gears for the entire track.

There are a couple of places where I use a 14/49 to bring second down a little and make the gears seem closer spaced.

But on the chain, assuming you are using a good strong one, and are also using high grade press fit master links, what would be wrong with using two masters part of the time and a add-in/leave-out link to make up the difference? I do.

  • fastenuf4u

Posted May 12, 2006 - 07:22 AM


Thanks for the replies. I can't believe I forgot you could increase the number of teeth by 1 on the countershaft sprocket to equal between 2-3 teeth on the rear. It would have saved me a bundle and allowed me to use the same chain and not mess with the setup too much. I guess since it should be arriving today I will have to just run a 14/47 setup and probably shorten the chain. This bike has enough pull I doubt I would need to go back to a 49 for any reason, if I do need that extra pull I will just downshift! Thanks again.

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