Sprocket sizing effect on chain wear

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Jan 30, 2018
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Looking at a sprocket change with the next chain replacement on my bike. I am looking at two options that offer darn close to the same drive ratio:
  1. 17 tooth front sprocket with a 47 tooth rear sprocket
  2. 16 tooth front sprocket with a 44 tooth rear sprocket
I recognize that there are chain length differences between these two setups--roughly 3 links different.
I see that the smaller setup has less slung mass.
I am assuming that with less overall teeth and less overall pins/links that the tolerable wear is lower, is that right and distinctly noticeable?
What else might I consider?
 
This question has been asked for ages by the motorcycle community.

As a broke kid trying to get 10 MPH of top end out of a 125 for a longer track it was always easier to change a front sprocket than a rear one cost wise - until the effect of doing so caught up with you and the chain stretched all the way to limit of the adjuster.
 
OK.
The current and stock sprocket setup is a 16T / 50T
I would surmise that the changes to the rear 50T -> 47T and 50T -> 44T are less significant.
The radius change moving from 16T up to 17T is more significant.
I would expect less chain wear than stock on 17/47, and marginally more chain wear than stock on 16/44.
Right track?
 
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No question, the larger engine sprocket is best if it fits.

There was always a rule of thumb about the ideal minimum number of teeth a sprocket should have. I think it used to be 19 teeth. Not that manufacturers took much notice. I can remember my Z900 in 1976 having the rather stupid choice of a longer pitch chain than standard which meant the engine sprocket had only 14 teeth. It never made sense as race bikes with vastly more power managed with a standard chain pitch. Anyway the Z900's big hefty chain broke when it was just out of warranty.
 
Going by the ratio here is what you're likely looking at...

50/16 =3.12 ratio (stock gearing with base line wear)
47/16 =2.93 ratio (geared higher than stock with more wear)
44/16 =2.75 ratio (geared even higher than stock with more wear)

50/17 =2.94 ratio (geared higher than stock with more wear)
47/17 = 2.76 ratio (geared even higher than stock with more wear)
44/17 =2.56 ratio (geared the highest than stock with more wear)

53/17 =3.11 ratio (equal to stock gearing with less wear)
53/16 =3.31 ratio (geared lower than stock with less wear)
 
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I wouldnt think one tooth difference on the front sprocket would be a large increase in wear. If you were dropping down to a 13 or 14 that would probably cause a noticeable difference over time.

Paco
 
The tooth count whether odd or even means more to chain wear than adding or reducing by a tooth either way. Odd numbers up front and in the rear create the best scenario for chain and sprocket life.
 
Of your original choices, I'm saying is 17/47 is your best bet for sprocket and chain life and that is what you surmised in post #7 but for a different reason. The radius is a factor, but less frequent chain contact (even number of links) on an odd-tooth sprocket makes the most difference. There really isn't a "roughly 3 links different" possibility, chains are an even number of links.
 
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