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Different sprockets, same ratio's, Benefits?

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Ok, just out of curiosity! 2 sets of sprockets with the same ratio's ( say an extreme example 15/45 and 12/36).

  Would there be any difference in performance? Does the gain in leverage on the 45 rear make up for the loss in the 15 front?

Not gonna change the old girls rings, just curious! Muzz.

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Ok, just out of curiosity! 2 sets of sprockets with the same ratio's ( say an extreme example 15/45 and 12/36).

  Would there be any difference in performance? Does the gain in leverage on the 45 rear make up for the loss in the 15 front?

Not gonna change the old girls rings, just curious! Muzz.

Smaller countershaft faster it will wear allso say a 12 if you could get one would eat up slider and cut into swingarm. I would never run smaller than 14 I have 14/45 on my L. Goggle gearing commmander

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I always go for the biggest sprockets that meet my needs.  I've had both 15/48 and 14/45 on my 2001, which is very close to the same ratio.  You can't tell which is which just by riding it.  But the smaller front sprocket causes more wear on the chain and swingarm.

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There is no appreciable hp/torque advantage either way. If anything smaller sprockets may have a minimally lower friction coefficient when new but certainly not enough to outweigh the longer life of the large option. Performance wise the larger sprockets will win in the long run. They will stay in good condition longer thereby losing efficiency slower than little sprockets. Also use odd numbered sprockets on both ends if possible too. A hunting ratio equalizes wear better giving the same benefit.

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Also use odd numbered sprockets on both ends if possible too. A hunting ratio equalizes wear better giving the same benefit.

And if you can't do that, you could always move the chain by one tooth every once in a while on the even sprockets to get more even sprocket wear.

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use the biggest front sprocket u can fit and get a back 1 to suit that will increase sprocket/chain life as it spreads the load over more area/teeth/links

but no power gain will be noticed either way as the ratio would still be the same

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Ok, just out of curiosity! 2 sets of sprockets with the same ratio's ( say an extreme example 15/45 and 12/36).

  Would there be any difference in performance? Does the gain in leverage on the 45 rear make up for the loss in the 15 front?

Ask yourself this: if the actual gear ratio remains unchanged, how could the torque multiplication ("leverage") change?

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There is no appreciable hp/torque advantage either way. If anything smaller sprockets may have a minimally lower friction coefficient when new but certainly not enough to outweigh the longer life of the large option. Performance wise the larger sprockets will win in the long run. They will stay in good condition longer thereby losing efficiency slower than little sprockets. Also use odd numbered sprockets on both ends if possible too. A hunting ratio equalizes wear better giving the same benefit.

 

 

I had to look "hunting ratio" up just now, never heard of it before. Makes sense though for wear over the long term. Learn something new every day on TT.  :thumbsup:

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The larger front sprocket will result in less chain friction which means less power loss.

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I know what he's asking and thought of it myself. Kind of like does a larger front take more torque than a smaller one even though the tire will end up turning at the same speed. I didn't feel it would make any measurable difference with such small differences. I always tried to keep my front as big as possible then change the rear to suit speed to rpm needs.

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The larger front sprocket will result in less chain friction which means less power loss.

Could you explain how it means less friction?

 

Less of the chain is touching the sprocket teeth at any one time.  What about a smaller sprocket increased friction?

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Yes, there is a benefit. In bikes it might not be so much since the power made and power curve are very useful, but when I drove karts with a yamaha RT100 2T engine, we messed with gearing 5-10 times per 2 hour practice session. The lower the gearing F&R, the faster you can accelerate to top speed. When you are gearing for your engine/rpm/autoclutch engagement to work together, it is much more important. With bikes, not so much.

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Odd number of teeth, will defiantly provide equal wear patterns. This design is used on all dozing and loading track hd equipment

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Could you explain how it means less friction?

 

Less of the chain is touching the sprocket teeth at any one time.  What about a smaller sprocket increased friction?

smaller sprocket means higher torque loading per tooth. Probably too many variables to translate that to more friction though. In general higher tooth counts on both sprockets give lower torque loads per tooth. Hunting ratios spread the wear more evenly. Always using at least an odd numbered counter sprocket will extend c/s and chain life a fair amount. An odd tooth count at the wheel helps even more. Bigger sprockets and longer chain will add weight that also will slow acceleration but the better wear is more important to me. Edited by valvesrule
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If the sprocket teeth on either end don't divide evenly into the number of chain links, then it's already going to hunt. An odd-linked chain is going to guarantee that.

 

I think most of us probably have a chain with the stock110 links There are no possible front sprockets that divide evenly into that and 55 is the only realistic size that might fit on the back.

 

As Shakespeare once said, "much ado about nothing."

 

smaller sprocket means higher torque loading per tooth. Probably too many variables to translate that to more friction though. In general higher tooth counts on both sprockets give lower torque loads per tooth.

 

The force of friction is ≤ the coefficient of friction times the force between surfaces, or F ≤ µN. A smaller sprocket has more force on each tooth, but fewer teeth. A larger sprocket has less force per tooth, but more teeth. Since they ultimately are equal, any friction increase from a larger sprocket can be be assumed to come from more pivots in the chain, more o-rings causing drag, etc. I would expect it to be negligible for anything but a maximum effort race machine.

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