Improved chain/sprocket life technique

Just great: I recently that a 32/17 is perfect for my SS MTB for the
trails I ride.

Sheesh.

Thanks for the info though -- it makes sense.

FWIW, I've had a lot of luck extending chain/sprocket life by rotating
between two chains every two weeks on a derailer bike. Some former
7-Eleven mechanic from Denver told me about that trick, and they used
to do that for the 7-Eleven pro team bikes.

Sheldon Brown said:

If you don't have derailer gears, there's a technique you can use to
extend the lifespan of your drivetrain parts. See my new article on this:

http://sheldonbrown.com/chain-life

Sheldon "Even Numbers" Brown
+--------------------------------------------------------------+
| When I think back on all the [censored] I learned in high school |
| It's a wonder I can think at all |
| And though my lack of education hasn't hurt me none |
| I can read the writing on the wall --Paul Simon |
+--------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Just great: I recently decided that a 32/17 is perfect for my SS MTB
for the trails I ride.

Sheesh.

Thanks for the info though -- it makes sense.

FWIW, I've had a lot of luck extending chain/sprocket life by rotating
between two chains every two weeks on a derailer bike. Some former
7-Eleven mechanic from Denver told me about that trick, and they used
to do that for the 7-Eleven pro team bikes.

Sheldon Brown said:

If you don't have derailer gears, there's a technique you can use to
extend the lifespan of your drivetrain parts. See my new article on this:

http://sheldonbrown.com/chain-life

Sheldon "Even Numbers" Brown
+--------------------------------------------------------------+
| When I think back on all the [censored] I learned in high school |
| It's a wonder I can think at all |
| And though my lack of education hasn't hurt me none |
| I can read the writing on the wall --Paul Simon |
+--------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

I buy KMC single speed chains at *mart for $5 and use DX cogs--about as
cheap to run as you can get.

Chainrings with my BCD are no longer made (old Suntour), but I've got
at least 20K left on this one, then I'll flip it over and ride it
another decade.

42/16 so should go quite a while according to Sheldon's theorizing.

Now if there was a way to make cassettes last longer, other than just
cleaning the thing fairly often--that would be the veritable water
powered SUV. 😄

I said:

Quoted message said:

If you don't have derailer gears, there's a technique you can use to
extend the lifespan of your drivetrain parts. See my new article on

this:

Quoted message said:

Quoted message said:

http://sheldonbrown.com/chain-life

An anonymous poster replied:

Quoted message said:

Just great: I recently decided that a 32/17 is perfect for my SS MTB
for the trails I ride.

According to my trusty slide rule, 32/17 is the same as 34/18 or 38/20.

Sheldon "http://sheldonbrown.com/sliderule" Brown
+-------------------------------------------------------+
| Discovery consists in seeing what everyone else has |
| seen and thinking what no one else has thought. |
| - Albert Szent-Gyorgi |
+-------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Sheldon Brown said:

According to my trusty slide rule, 32/17 is the same as 34/18 or 38/20.

I've tried explining that to my current drivetrain, but it resists
growing any new teeth. Can your slide rule talk some sense into it?

two 21 tooth middle cassette cogs not one is another step in this
direction
or 3!!

factor 3
http://www.sec.noaa.gov/SWN/

Sheldon Brown said:

If you don't have derailer gears, there's a technique you can use to
extend the lifespan of your drivetrain parts. See my new article on this:

http://sheldonbrown.com/chain-life

Whoa, that is cool.

JT

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mindbuckling!

Worthwhile idea, but your number theory is a bit off. The main issue
is the relative divisibility of the cog size and the number of chain
links.

For instance, if you have a 17-tooth cog and the number of chain links
is a multiple of 17, then each link will hit the same tooth on every
revolution of the chain. In that case it might be better to mark the
exact tooth that a link engages before removal.

In general, the greatest common divisor (gcd) of the chain links and
the cog size tells you the number of "tooth subgroups" you have. For
instance, if the gcd is 2, then you have the even/odd parity that you
describe (there are two sets of teeth/links which don't intermingle,
but every "even" link meets every "even" tooth eventually). If the gcd
is 1, then every tooth engages every link at some point, and so on.

Chains require an even number of links (unless you use a half-link).
Thus, even-toothed cog teeth will always mate the same type of link.

Quoted message said:

Worthwhile idea, but your number theory is a bit off. The main issue
is the relative divisibility of the cog size and the number of chain
links.

For instance, if you have a 17-tooth cog and the number of chain links
is a multiple of 17, then each link will hit the same tooth on every
revolution of the chain. In that case it might be better to mark the
exact tooth that a link engages before removal.

In general, the greatest common divisor (gcd) of the chain links and
the cog size tells you the number of "tooth subgroups" you have. For
instance, if the gcd is 2, then you have the even/odd parity that you
describe (there are two sets of teeth/links which don't intermingle,
but every "even" link meets every "even" tooth eventually). If the gcd
is 1, then every tooth engages every link at some point, and so on.

Quoted message said:

Worthwhile idea, but your number theory is a bit off. The main issue
is the relative divisibility of the cog size and the number of chain
links.

For instance, if you have a 17-tooth cog and the number of chain links
is a multiple of 17, then each link will hit the same tooth on every
revolution of the chain.

Yes, quite true - but the *type* of links (inner-plate vs. outer-plate)
that hit the tooth will alternate if the cog has an odd number of teeth.
Sheldon's method isn't about having the links hit the same tooth each
time, it's about having only one *type* of link ever hit a particular tooth.

In that case it might be better to mark the

Quoted message said:

exact tooth that a link engages before removal.

In general, the greatest common divisor (gcd) of the chain links and
the cog size tells you the number of "tooth subgroups" you have. For
instance, if the gcd is 2

(i.e. if the cog has an even number of teeth - chains always have an
even number of links if each pair of sideplates constitutes one "link"😉

, then you have the even/odd parity that you

Quoted message said:

describe (there are two sets of teeth/links which don't intermingle,
but every "even" link meets every "even" tooth eventually). If the gcd
is 1, then every tooth engages every link at some point, and so on.

Mark "Remember, 28 teeth is a perfect number!" Janeba