Small derailleur sprockets

On Sat, 21 Feb 2015 11:30:25 +0000 (GMT),
(Nick Maclaren) wrote:

In article ,
John B. Slocomb wrote:

Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.

My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.

I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.

Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(

I suspect that in terms of a bicycle it isn't overly important, or
perhaps not easily corrected. A 25 tooth rear sprocket would require a
113 tooth front sprocket to match the usual 50/11 road gearing.

Oh, it's important, all right! Derailleurs are chain and sprocket
eaters, at best (fixed and hub gears have a VASTLY higher distance
between maintenance, and even more between replacement). But many
vendors like selling short-life equipment, because they make their
profit on the replacements.

It's soluble only by using hub gears or by even more drastic
measures.


Regards,
Nick Maclaren.

But I wonder, is it is the derailer that is to blame, or the sprocket
size (the original point under discussion) the cause.
--
Cheers,

John B.

On Sat, 21 Feb 2015 06:05:10 -0800 (PST), Mike A Schwab
wrote:

On Saturday, February 21, 2015 at 5:30:27 AM UTC-6, Nick Maclaren wrote:
In article ,
John B. Slocomb wrote:

Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.

My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.

I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.

Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(

I suspect that in terms of a bicycle it isn't overly important, or
perhaps not easily corrected. A 25 tooth rear sprocket would require a
113 tooth front sprocket to match the usual 50/11 road gearing.

Oh, it's important, all right! Derailleurs are chain and sprocket
eaters, at best (fixed and hub gears have a VASTLY higher distance
between maintenance, and even more between replacement). But many
vendors like selling short-life equipment, because they make their
profit on the replacements.

It's soluble only by using hub gears or by even more drastic
measures.


Regards,
Nick Maclaren.

The main determinant is pressure per area. Once you exceed the material strength of the parts, it starts wearing quickly.

Actually, after you exceed the material strength of the parts they
break :-)

Single speed / hub gears use wider chains with more area. 5-7 freewheels are almost as good. 7-11 cassettes get thinner and thinner and wear much more quickly.

Dirt causes wear because it causes all the pressure to be against the piece of dirt instead of the entire surface area.
--
Cheers,

John B.

On 21/02/15 19:58, Nick Maclaren wrote:
In article ,
John B. Slocomb wrote:

Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.

My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.

I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.

Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(


So a 39 chainring and an 11 tooth sprocket makes 50 teeth. Great! Not
that I use the 12 or 11 with the small ring, but it's handy to know the
wear shouldn't be to bad with my UCI racing gears...

--
JS

On 21/02/15 21:30, Nick Maclaren wrote:
In article ,
John B. Slocomb wrote:

Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.

My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.

I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.

Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(

I suspect that in terms of a bicycle it isn't overly important, or
perhaps not easily corrected. A 25 tooth rear sprocket would require a
113 tooth front sprocket to match the usual 50/11 road gearing.

Oh, it's important, all right! Derailleurs are chain and sprocket
eaters, at best (fixed and hub gears have a VASTLY higher distance
between maintenance, and even more between replacement). But many
vendors like selling short-life equipment, because they make their
profit on the replacements.

It's soluble only by using hub gears or by even more drastic
measures.


How many kilometres do you get from a single speed before the sprocket
and chain is really badly worn?

--
JS

On 22/02/15 03:55, Martin Borsje wrote:
Lou Holtman formulated the question :
On 2015-02-21 11:30:25 +0000, Nick Maclaren said:

In article ,
John B. Slocomb wrote:

Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.

My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.

I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific
calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.

Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(

I suspect that in terms of a bicycle it isn't overly important, or
perhaps not easily corrected. A 25 tooth rear sprocket would require a
113 tooth front sprocket to match the usual 50/11 road gearing.

Oh, it's important, all right! Derailleurs are chain and sprocket
eaters, at best (fixed and hub gears have a VASTLY higher distance
between maintenance, and even more between replacement). But many
vendors like selling short-life equipment, because they make their
profit on the replacements.

My experience on my singlespeed and Rohloff hubbed bikes is that the
chains and sprockets don't last longer that the chains and cassettes
on my derailleur equipped bikes. It is true that you can ride longer
with a worn chain and sprocket without getting into trouble. The
sprocket on my Rohloff ATB lasted 1500 km. When I replaced the chain
the new chain made a terrible noise. I reversed the sprocket and the
noise was gone. 1500 km is a pathetic mileage even for a ATB used
mostly in dirty conditions. The same goes for my singlespeed.


It's soluble only by using hub gears or by even more drastic
measures.

Not in my case.

My sprocket on my Rohloff ATB lasts already 3000 km, almost all rides in
dirty wet conditions.

My third chain although on it - no problems so far...

Keep my fingers X'ed.

I've alternated the running of 2 chains on my one 10 speed cassette and
closing in on 16,000km so far.

--
JS

James wrote:
On 21/02/15 19:58, Nick Maclaren wrote:
In article ,
John B. Slocomb wrote:

Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.

My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.

I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.

Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(


So a 39 chainring and an 11 tooth sprocket makes 50 teeth. Great! Not
that I use the 12 or 11 with the small ring, but it's handy to know the
wear shouldn't be to bad with my UCI racing gears...


Hmmm. You must really be able to extend the life climbing those 18% grades
in the 39/28 then.
--
duane

On Mon, 23 Feb 2015 13:53:45 +1000, James
wrote:

On 21/02/15 21:30, Nick Maclaren wrote:
In article ,
John B. Slocomb wrote:

Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.

My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.

I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.

Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(

I suspect that in terms of a bicycle it isn't overly important, or
perhaps not easily corrected. A 25 tooth rear sprocket would require a
113 tooth front sprocket to match the usual 50/11 road gearing.

Oh, it's important, all right! Derailleurs are chain and sprocket
eaters, at best (fixed and hub gears have a VASTLY higher distance
between maintenance, and even more between replacement). But many
vendors like selling short-life equipment, because they make their
profit on the replacements.

It's soluble only by using hub gears or by even more drastic
measures.


How many kilometres do you get from a single speed before the sprocket
and chain is really badly worn?

An even better question is "how far up the hill do you get with your
single speed before you get off and push " :-)
--
Cheers,

John B.

On Saturday, February 21, 2015 at 10:33:47 AM UTC-8, Lou Holtman wrote:
Martin Borsje wrote:
Lou Holtman formulated the question :
On 2015-02-21 11:30:25 +0000, Nick Maclaren said:

In article ,
John B. Slocomb wrote:
Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.
My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.
I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.
Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(
I suspect that in terms of a bicycle it isn't overly important, or
perhaps not easily corrected. A 25 tooth rear sprocket would require a
113 tooth front sprocket to match the usual 50/11 road gearing.
Oh, it's important, all right! Derailleurs are chain and sprocket
eaters, at best (fixed and hub gears have a VASTLY higher distance
between maintenance, and even more between replacement). But many
vendors like selling short-life equipment, because they make their
profit on the replacements.

My experience on my singlespeed and Rohloff hubbed bikes is that the
chains and sprockets don't last longer that the chains and cassettes
on my derailleur equipped bikes. It is true that you can ride longer
with a worn chain and sprocket without getting into trouble. The
sprocket on my Rohloff ATB lasted 1500 km. When I replaced the chain
the new chain made a terrible noise. I reversed the sprocket and the
noise was gone. 1500 km is a pathetic mileage even for a ATB used
mostly in dirty conditions. The same goes for my singlespeed.

It's soluble only by using hub gears or by even more drastic
measures.

Not in my case.

My sprocket on my Rohloff ATB lasts already 3000 km, almost all rides in
dirty wet conditions.

My third chain although on it - no problems so far...

Keep my fingers X'ed.

Hmm, three chains for 3000 km. It was obvious that I waited a bit to long
replacing the chain. Your numbers prove that. Bottom line is that my
experience is that the same chain wears as fast on a single speed or
gearhub setup as on a derailleur setup.


What kind of chain are you using? I know Rohloff says 3/32" and not 1/8", but I assume you could use a beefy 5 speed chain. No?

-- Jay Beattie.

On Tuesday, February 24, 2015 at 2:06:18 AM UTC+1, jbeattie wrote:
On Saturday, February 21, 2015 at 10:33:47 AM UTC-8, Lou Holtman wrote:
Martin Borsje wrote:
Lou Holtman formulated the question :
On 2015-02-21 11:30:25 +0000, Nick Maclaren said:

In article ,
John B. Slocomb wrote:
Does anyone know of an engineering or experimental reference to
how the rate of wear of a sprocket varies with number of teeth?
All of Renolds, Rexnord and Diamond strongly disrecommend below
13 teeth, and advise more, but the reason is irregularity of
speed, not rate of wear.
My experience from a long time back with hub gears is that it is
highly non-linear once you get below (say) 16 teeth.
I took a quick look and there apparently is a correlation between
sprocket size and wear although I didn't find a specific calculation I
did find a reference that in a low ratio chain drive the total number
of drive and driven teeth, for best longevity, should not be less
than 50, i.e., a 25 tooth driver and a 25 tooth driven which seems to
be indicative.
Thanks. This could be another of the important aspects of cycling
that is ignored because it isn't important to UCI racing :-(
I suspect that in terms of a bicycle it isn't overly important, or
perhaps not easily corrected. A 25 tooth rear sprocket would require a
113 tooth front sprocket to match the usual 50/11 road gearing.
Oh, it's important, all right! Derailleurs are chain and sprocket
eaters, at best (fixed and hub gears have a VASTLY higher distance
between maintenance, and even more between replacement). But many
vendors like selling short-life equipment, because they make their
profit on the replacements.

My experience on my singlespeed and Rohloff hubbed bikes is that the
chains and sprockets don't last longer that the chains and cassettes
on my derailleur equipped bikes. It is true that you can ride longer
with a worn chain and sprocket without getting into trouble. The
sprocket on my Rohloff ATB lasted 1500 km. When I replaced the chain
the new chain made a terrible noise. I reversed the sprocket and the
noise was gone. 1500 km is a pathetic mileage even for a ATB used
mostly in dirty conditions. The same goes for my singlespeed.

It's soluble only by using hub gears or by even more drastic
measures.

Not in my case.

My sprocket on my Rohloff ATB lasts already 3000 km, almost all rides in
dirty wet conditions.

My third chain although on it - no problems so far...

Keep my fingers X'ed.

Hmm, three chains for 3000 km. It was obvious that I waited a bit to long
replacing the chain. Your numbers prove that. Bottom line is that my
experience is that the same chain wears as fast on a single speed or
gearhub setup as on a derailleur setup.


What kind of chain are you using? I know Rohloff says 3/32" and not 1/8", but I assume you could use a beefy 5 speed chain. No?

-- Jay Beattie.

I just use 9 speed chains. First Sram PC9something and now as an experiment a Campa C9, which is definitely more durable. I could use a beefier chain, but I have to have already 9,10, 11 speed chains in stock for my other bikes so I use the 9 speed. I tried once a really beefy and really heavy chain for a track bike because I had issues dropping the chain in a bumpy curve with my singlespeed. That was because I used a chainring and a single cog meant for a derailleur system with bent tooths, half tooths to improve shifting. I learned the hard way that this is a no go for a singlespeed and gearhub bikes, so now I use a cog and a chainring with straight tooths meant for singlespeeds. The track chain was very noisy even after aligning the chainring and cog accurately. A derailleur chain runs very silent. The limited lifetime is no problem but everytime I hear people saying the the fact that the straight chainline of a singlespeed and gearhub bikes increase the lifetime I mention that that is not my experience. Even the beefy and steel cog of the Rohloff hub wears with a worn chain and the chain wears as quickly as the same chain on a derailleur system. The influence of a little cross chaining on the chain wear is insignificant. Because you only have one cog and chainring you don't get into trouble with a worn chain as long as you can adjust the chain tension. If you run out of adjustability you have to replace chain, chainring and cog though. I replaced chains on Dutch citybikes the were stretched almost 2 links something you can't get away with with a derailleur system. People who are only using Dutch utility bikes with a gearhub never have to replace the chain if they buy a new bike, let say, every 3-5 years and are very surprized when I tell them this is standard maintenance on a roadbike and even more on a ATB. They think their chain doesn't wear because of the enclosed chainguard but in reality the chain does wear but they can get away with it.

Lou

Lou Holtman wrote:
:I just use 9 speed chains. First Sram PC9something and now as an
:experiment a Campa C9, which is definitely more durable. I could use a
:beefier chain, but I have to have already 9,10, 11 speed chains in stock
:for my other bikes so I use the 9 speed. I tried once a really beefy
:and really heavy chain for a track bike because I had issues dropping
:the chain in a bumpy curve with my singlespeed. That was because I used
:a chainring and a single cog meant for a derailleur system with bent
:tooths, half tooths to improve shifting. I learned the hard way that this
:is a no go for a singlespeed and gearhub bikes, so now I use a cog and a
:chainring with straight tooths meant for singlespeeds. The track chain
:was very noisy even after aligning the chainring and cog accurately. A
:derailleur chain runs very silent. The limited lifetime is no problem but
:everytime I hear people saying the the fact that the straight chainline
f a singlespeed and gearhub bikes increase the lifetime I mention that
:that is not my experience. Even the beefy and steel cog of the Rohloff
:hub wears with a worn chain and the chain wears as quickly as the same
:chain on a derailleur system. The influence of a little cross chaining
n the chain wear is insignificant. Because you only have one cog and
:chainring you don't get into trouble with a worn chain as long as you
:can adjust the chain tension. If you run out of adjustability you have
:to replace chain, chainring and cog though. I replaced chains on Dutch
:citybikes the were stretched almost 2 links something you can't get away
:with with a derailleur system. People who are only using Dutch utility
:bikes with a gearhub never have to replace the chain if they buy a new
:bike, let say, every 3-5 years and are very surprized when I tell them
:this is standard maintenance on a roadbike and even more on a ATB. They
:think their chain doesn't wear because of the enclosed chainguard but in
:reality the chain does wear but they can get away with it.
:

I have somthing like 3K miles on my 8sp shimano. I've gone through a
couple chains, from rusting (they pave the roads with salt in
chicago), not wear. There was no visible wear on the cog or
chainring when I last changed chain. I supsect rolholf uses chesse to
make their cogs.

--
sig 59