Ian H
Ancient randonneur
It doesn't matter what causes the stretch, it still won't mesh properly with the cogs, so the cogs will wear more rapidly.
Half link chain stretch
- Thread starter MossCommuter
- Start date
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Rohloff_Brompton_Rider
Formerly just_fixed
The chain will wear with the sprocket, removing a link will not suddenly make the chain skip.
Yellow Saddle
Guru
- Location
- Loch side.
I doubt that a half link chain straightens out with use. For that to happen the chain will have to go into yield by some huge force. Such a force can only be a stomp on the pedals and as such, will only stretch the portion of the chain between the front and rear sprockets in the tension cycle. That means the chain will be elongated in some sections and perfect in others. If anyone has such a chain, I'd be very keen to examine it.
Rohloff_Brompton_Rider
Formerly just_fixed
It is well known in the world of ss/fixed riding that half link chains do indeed straighten out very quickly. Just have a search on the LGFSS forum, there's lots of anecdotal evidence on there.
Yellow Saddle
Guru
- Location
- Loch side.
OK, but by what mechanism? Gradual force over repeated cycles does not stretch steel. It has to go into yield and I can't envisage anything we do on bicycles that would do that. It would be very easy to verify by measuring. Further, when we find a chain that's been stretched in that mode, we should be able to open it up end look at the pins which should have less wear than what is normal for a chain elongated to a certain length. Like I say, if anyone has a chain they suspect has stretched instead of worn, I'd like to examine it.
Rohloff_Brompton_Rider
Formerly just_fixed
Simple really, a kinked plate over twice as many links. Each bit only needs a little x lots of links = one link. I've had one or two over the years on conversions and they really do need links removing quite often.
Edit: it's not stretching steel - it's straightening it.
Edit: it's not stretching steel - it's straightening it.
Rohloff_Brompton_Rider
Formerly just_fixed
Plus with rear facing track ends, you don't even need to measure to see it.
andrew_s
Legendary Member
- Location
- Gloucester
Chain "stretch" is due solely to wear at the pins and the side plate bulges around them (what would be the bushings on an old style chain). The side plates don't straighten out*, and there's no extra wear on a half-link chain than on a normal chain - you've got the same number of pin/bushing interfaces wearing away as a regular chain.
* straightening out would still mean taking the metal past its elastic limit, and that's something that happens on occasional overload rather than by repeated normal use. You would find that strong riders would sometimes stretch a new chain in one ride if the kinks were straightening.
If half link chains do wear faster, it's more likely that it's because the design allows grit to get inside the links more easily.
In general, a replacement chain will skip on an old sprocket if the old chain was stretched by 1% or more. That will be the case if the axle has been move back in the dropouts by more than about 5mm. Singlepeed/fixed won't actually skip like gears unless the chain's slack, but 1% is still a reasonable indicator of when chain and sprocket mismatch causes faster wear.
If the axle has been moved by more than 5mm, which it probably has if you are thinking about taking out a half link, then you may as well just take out the half link and carry on using the chain.
If the axle hasn't moved that far, it's a matter of balancing the cost of a new freewheel (and possibly chainring) when the chain does eventually give up the ghost against the cost of replacing multiple chains when only part worn, to make the freewheel last longer. White freewheel are fairly expensive, so it may well be worth taking the regular change route.
* straightening out would still mean taking the metal past its elastic limit, and that's something that happens on occasional overload rather than by repeated normal use. You would find that strong riders would sometimes stretch a new chain in one ride if the kinks were straightening.
If half link chains do wear faster, it's more likely that it's because the design allows grit to get inside the links more easily.
In general, a replacement chain will skip on an old sprocket if the old chain was stretched by 1% or more. That will be the case if the axle has been move back in the dropouts by more than about 5mm. Singlepeed/fixed won't actually skip like gears unless the chain's slack, but 1% is still a reasonable indicator of when chain and sprocket mismatch causes faster wear.
If the axle has been moved by more than 5mm, which it probably has if you are thinking about taking out a half link, then you may as well just take out the half link and carry on using the chain.
If the axle hasn't moved that far, it's a matter of balancing the cost of a new freewheel (and possibly chainring) when the chain does eventually give up the ghost against the cost of replacing multiple chains when only part worn, to make the freewheel last longer. White freewheel are fairly expensive, so it may well be worth taking the regular change route.
Rohloff_Brompton_Rider
Formerly just_fixed
Sorry dude, just google oogle half link chain wear. And you'll see your assumptions and imagined engineering knowledge, are quite incorrect my dear fellow.
bikeman66
Senior Member
- Location
- Isle of Wight
Why bother asking a question on the forum if you're not going to take the advice of the majority of people who respond, rather than wait for one solitary answer that corresponds with what you wanted to hear?
I guess you could wring every last mile out of that chain, but in all honesty, as it stretches it will cause premature wear on the chainrings and sprockets. Ideally, the most satisfactory thing for complete peace of mind and reliable function is to replace chain, chainrings and sprocket/cassette at the same time, but in practice you should get two chains worth out of the other components.
A new chain is hardly going to break the bank is it, but when you're talking chain, chainrings and sprocket, that's when it starts getting expensive. Your choice I suppose!
I guess you could wring every last mile out of that chain, but in all honesty, as it stretches it will cause premature wear on the chainrings and sprockets. Ideally, the most satisfactory thing for complete peace of mind and reliable function is to replace chain, chainrings and sprocket/cassette at the same time, but in practice you should get two chains worth out of the other components.
A new chain is hardly going to break the bank is it, but when you're talking chain, chainrings and sprocket, that's when it starts getting expensive. Your choice I suppose!
OP
OP
MossCommuter
Guru
- Location
- Salford
OP
OP
MossCommuter
Guru
- Location
- Salford
I was joking - I changed the chain.
