Chain Stretch

On Sunday, September 17, 2017 at 6:40:54 PM UTC+2, wrote:
On Saturday, September 16, 2017 at 10:45:12 PM UTC-7, wrote:
On Sunday, September 17, 2017 at 12:30:48 AM UTC+2, wrote:
On Friday, September 15, 2017 at 4:49:05 AM UTC-5, John B. wrote:
I've been thinking about chain wear, sometimes called chain stretch,
and have done a bit of research on the subject.

One method is to lay the chain on a flat surface and measure the wear
over, perhaps 12 inches of chain length, from the head of one pin to
another. But modern multi speed chains are a bit more complex then the
old fashioned chains and the rollers on a modern chain are not
supported by the pins but by protrusions on the inner surface of the
inner links thus does the distance from roller to roller relate to
distance from pin to pin?

Another method is to ignore the pin to pin distance and simply measure
the roller to roller distance using a chain gauge. But I have also
read that when comparing roller to roller measurement to pin to pin
measurement there is not necessarily a correlation, or in other words
a pin to pin measurement might show one thing while the roller to
roller might show a totally different wear pattern. In addition I read
that in at least one case the roller to roller wear was not constant
and varied from place to place in the length of the chain

Brandt, I believe, wrote a treatise on chain measuring gauges and
argued that nearly all of them gave an incorrect figure for wear, or
perhaps, did it the wrong way.

So the question is what is the best system to use to avoid unnecessary
sprocket wear, assuming that sprockets cost more and are more trouble
to change than chains.

There seems to be three options. One, to use a ruler and measure from
pin to pin. Two to use a chain tool and measure from roller to roller.
Or three, to use some combination of the two.

Or perhaps there is a fourth - ignore the whole thing as a tempest in
a tea pot :-)
--
Cheers,

John B.

Since the switch to cassettes (8+ cogs) from freewheels https://www.sheldonbrown.com/free-k7.html , the axle width has remained the same while the cog teeth and chains have become narrower. Since the load and the length are the same, the pressure per square inch has increased to the point where an 11 speed chain basically needs changed with the tire. Single speed chains will basically last until rusty.

I get 3 tires out of a 11 speed chain and if the same criteria is used for replacement for a single speed chain as for a 11 speed than the difference is that much.

Lou, I understood the first bit well enough but couldn't quite make out the single speed chain wear part.

Tom I rode a single speed for a long time in the winter and the last years a bike with a gear hub (I'm getting old) and the chains on those bikes wore much faster than the chains on my road bikes. Of coarse the conditions are different but not so much that it would explain the wear rate. You can get away with it as long as you don't replace the cog and the chain ring until the teeth are completely gone and that takes a long time.

You must either buy cheap tires or ride a hell of a lot more than I do in order to wear out 3 tires per chain.


I ride 7000 km on my road bikes, that means two new rear tires. I use only Continental GP4000S. Chains are Campagnolo Record 11 speed. Most of the times I get 10000 km out of that chain except this last time when I encountered a remarkable difference between the chains on my two road bikes.

https://photos.app.goo.gl/vZ4zMH61d6mGl84C2

From top to bottom: new chain, chain on one road bike after about 9500 km and the chain on the other road bike after 7500 km. Only difference I see is that I used a different lube for a while. Still puzzles me.

Lou


I wear out perhaps a Gatorskin and a half per chain. But I mostly replace chains early since they're relatively cheap and better a chain than wearing out a cassette.