Probably a pointless chain stretch question

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Svendo

Guru
Location
Walsden
Thanks for the reply reiver, but, cripes, you worry me! By the by, only 54 links?
I think User9609 means 'full' links, an inner and an outer, nominally an inch long. 108 is a quite reasonable chain length in 'half' links, which seem to be most commonly used these days e.g. Web shops and packaging.
 

Svendo

Guru
Location
Walsden
[QUOTE 4641183, member: 9609"]
I take the chain off every week and digitally measure its full 54 links length. I have got quite good at it and can measure the wear in a 25 mile ride ![/QUOTE]
That sounds impressive, how do you do it? My digital calipers aren't that long! @User9609
 

Ajax Bay

Guru
Location
East Devon
[QUOTE 4643989, member: 9609"]I know I'm slightly mad, but it does keep me amused[/QUOTE]
Previously 'OCD' has been (unreasonably imo) ascribed to this behaviour by "can't remember who" - YS.
You are bloody OCD but you know that, don't you? Keep it up, I love it.
Thank you very much for sharing that detail.

Here's a bit more I've dredged up (click to expand to get the images).
[QUOTE 4474823, member: 9609"]for my long term lube tests I measured the whole length of the chain, it is the only way to observe the minute changes that take place every 100 mile. I permanently attached a ruler to a board in the garage and measured all 54 links.
In the example below I measure this old chain at 1381.3mm 0.7% wear. (i like to bin them off before this point)
Roughly I will observe about 1mm of wear per 100 miles

On aspect of chain wear that no one mentions is how much ascent has been done. I haven't got any exact figures yet, but certainly chain wear on a flat ride could be half that of on a hilly ride
View attachment 321452

View attachment 321453 [/QUOTE]
 

Svendo

Guru
Location
Walsden
Previously 'OCD' has been (unreasonably imo) ascribed to this behaviour by "can't remember who" - YS.

Thank you very much for sharing that detail.

Here's a bit more I've dredged up (click to expand to get the images).
I'd say this behaviour is more ASD (aspeger's) than OCD unless there are some irrational dire consequences User9609 is avoiding by doing this (i.e. The 'O' in OCD). ;-)
 

Tony78

Active Member
Location
Liverpool
You can tell by the profile on the mainly used front chainring teeth what overall condition the drivetrain is in, hooked teeth means it's fubar but it would slip long before that.
My chain is slipping on big chainring, chain pulls away from ring, couple off hook looking teeth, but all other cogs and teeth look fine. other than the big ring,the bike's running fine, is the chain pulling off big ring due to just big chain ring wear?
 

keithmac

Guru
If you're on the big chain ring most of the time then it will wear out quicker.

I'd be tempted to fit a new big ring and a new chain, and see how you get on with the rear gears, if it skips it means the rear cassette is worn.
 

Ajax Bay

Guru
Location
East Devon
My chain is slipping on big chainring, chain pulls away from ring
If the chain pulls away then it's likely to be elongated through wear. How many miles has the chain done? Recommend chain replacement first. It's likely also that your cassette has worn (because of the well worn chain) - as you may discover once you put a new chain on. Chain rings are sturdy and long wearing: often more than 100,000km. I guess that few (ie a minute percentage) need to be replaced because of wear.
 

Dogtrousers

Kilometre nibbler
My chain is slipping on big chainring, chain pulls away from ring, couple off hook looking teeth, but all other cogs and teeth look fine. other than the big ring,the bike's running fine, is the chain pulling off big ring due to just big chain ring wear?
Are you sure those worn looking teeth aren't meant to be like that? Modern chainwheels have shaped teeth aligned with pins on the inside to ease shifting.

(Apols if teaching gran to suck eggs)
 

Dogtrousers

Kilometre nibbler
Warning: Off topic detour.

Wandering way off topic, but probably not worth a thread of its own, I came across this from Feb 2016

https://www.bikerumor.com/2016/02/0...h-to-make-lighter-better-shifting-chainrings/

Shimano patent for a chainring with every other tooth missing.

Which led me off on a flight of fancy and I read this
http://www.classiclightweights.co.uk/extras/inch-pitch-block-chain.html

A history of changes in chain technology, particularly in track racing, with a brief detour via Moser's breaking of the 50km hour and Obree's and Boardman's aerodynamic advances and the other Tommy Godwin, the track cyclist.
 

Tim Hall

Guest
Location
Crawley
[QUOTE 4643989, member: 9609"]I know I'm slightly mad, but it does keep me amused - the full length of the chain is hung from a pin on a board and the other end aligns with a pre pleaced ruler, I can then measure with high accuracy with a digital camera, may be down to a 100th of a mm over 54 links
The one here calculated out as 1377.798mm for 54 links, therefore 0.452% worn. It is not perfect but will show the wear over a 50 mile ride. I am trying to compare wear from hilly rides to flat rides but my results are a little confusing (probably due to minor inaccuracies with dirt (I'm trying to improve it all the time)

View attachment 333970

View attachment 333971 [/QUOTE]
Aren't you getting using a higher level of precision than is sensible? Or, to put it another way, have you taken temperature into consideration?
Steel has a coefficient of linear expansion of 12 x 10^-6/K. Assuming a 20 degree temperature change (say the difference between summer and winter), and a chain length of 54 x 25.4 = 1371.6mm, then expansion will be:

1371.6 x 12 x 10^-6 x 20 = 0.33mm

(waits for someone to point out a glaring error)
 

Ajax Bay

Guru
Location
East Devon
He thinks I jinxed his bike! (I have a bit of a reputation for it - I once mentioned broken spokes to @Steve H on a forum ride and he broke one a few seconds later ... :whistle:)
Well then, it must have been an amazing coincidence that I warned of THIS CHAIN FAILURE a few seconds before it happened! :okay:
(The musclebound bodybuilder non-cyclist did NOT change gear, that was the problem! He used brute force to force the pedals round on a climb.)
Not a coincidence; you jinxed his chain, just like your brother/b-i-l's BB (first part of first quote).
Alternatively, he had already damaged it - this maltreatment was the final straw - as he was in the habit of changing gears, several at a time, under load when the road turned sharply up.
 
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