- This topic has 14 replies, 14 voices, and was last updated 11 years ago by Onzadog.
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0.75%
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billytinkleFree MemberPosted 11 years ago
Do people really replace chains when they are 0.75% worn?
Only a month or two ago I replaced my cassette, rings and chain after it was slipping all over the show after a year of usage, not silly money, but not cheap either.
I ride about 100 miles a week, so I expect to have put around 400 – 800 miles on it all. My new chain wear indicator (having never bothered before) tells me that it’s 0.75% worn now and should therefore think about replacement.
So what do you do? Replace at 0.75%? 1%? Or just when the whole lot becomes a pile of junk?
brFree MemberPosted 11 years agoIf you wait past 1% it’ll wear out the cassette quicker, so somewhere between .75% and 1% is the place to change it.
cynic-alFree MemberPosted 11 years agoI’m not convinced it makes any difference whether you rotate 3 chains around or just ride everything into the ground.
unklehomeredFree MemberPosted 11 years agoI’ve been being good on chain wear/use recently. Not sure what I read into it, but I found the third chain wore down very quickly, which I put down to everything else being a little worn, so am now running the lot into the ground.
PaulDFree MemberPosted 11 years agoRead up on chain checkers….some measure external rivet-rivet (like a ruler along the outside only), others measure the internal wear including the rollers…and that is always a much greater value.
Recently measured a CN 7800 at .75% internally, but under .25% externally.
It is also interesting to measure internally when new….I have had single speed KMCs showing 0% and 9-sp showing ~0.4%.
PaulD
breadcrumbFull MemberPosted 11 years agoI normally change just before 1%.
I was going to run the SS drivetrain into the ground but seeing as the chains are only £5.99 when you buy 3 or more it seemed a bit of a waste.
JunkyardFree MemberPosted 11 years agoI’m not convinced it makes any difference whether you rotate 3 chains around or just ride everything into the ground.
THIS from experi3nce I tyhink it ios bobbins tpo get you to buy stuff
My two worst
7 speed chain , 9 speed brand new cranks – chain stretched well over 1 % and was fine
I swapped around with other bits to see and got no skipping no matter what i did
Road bike as above took a new cassette without issue and changed fine.
There is no science on this I am aware of and engines for example use chains for timing without the need to change [ well they did pre cam belts]as often as we have to.
Some folk swear by it and some think it is marketing tosh
Experience says to me the later and i change it when it no longer works.pootleFree MemberPosted 11 years agoI bought a new bike 9 months ago and only recently measured the chain, finding that it had stretched by 1%. I decided to change it, but then found it slipping so had to change the cassette as well. I reckon if I’d stuck with the old chain and cassette I’d have got plenty more wear.
So either change the chain regularly or wait and replace everything – don’t follow my half arsed approach!
pdwFree MemberPosted 11 years agoWhat PaulD said. Most chain checkers over-read, sometimes to extent of declaring a brand new chain to be need of replacement. I use a set of calipers, shove it up against the edge of an outer plate and measure to the same point on a link over 5″ or 6″.
In my experience, measure it properly and the 0.75% rule is pretty much spot on. I’ve replaced at around 0.70% stretch and had no trouble. Last time I replaced my MTB chain, the new one slipped all over the place on the old cassette, measured it and it was on 1%.
I don’t know if it works out cheaper overall. The chain on my commuter will do 3-5k, and I’m hoping the cassette will see out three chains. It’s hard to know how many miles I’d get if I ran it into the ground, but when I’ve taken this approach in the past I’ve ended up changing chainrings as well, so it ends up reasonably expensive.
njee20Free MemberPosted 11 years agoNow cassettes are so expensive I aim to change chains more regularly. Last time I changed it it skipped, so I put the old chain back on, that was 9 months ago, it’s still fine! A bit rattly, but certainly does the job, would’ve been a pain to bin an XTR cassette which was still alright.
jota180Free MemberPosted 11 years agoI change them if they go beyond 1% and I reckon that a cassette lasts about 3 chains and crank rings 6
TBH though, I don’t methodically check them, just every now and then
TrimixFree MemberPosted 11 years agoI bought a chain checker and tried all that rotating, measuring bollocks.
Now I dont bother. I just ride till something slips and change the whole lot. Cheap chain, cheap cassette, 1×10. I end up putting a new set on once a year for very little money. No bother measuring chains and messing about.
I ride all year round, pretty much three / four times a week. Oh, and I dont oil my chain, just WD40 after I wash it. I found oiling it just made the mud and grit stick to it.
stevewhyteFree MemberPosted 11 years ago. Oh, and I dont oil my chain, just WD40 after I wash it. I found oiling it just made the mud and grit stick to it.
Ditto, I use GT85 after washing the bike, have done for 25 years, never had a problem. Bike chains need very little lubrication due to the fact there is very little heat build up. In my experience what kills chains is letting moisture sit on them and allowing them to rust.
WD or GT works well.
OnzadogFree MemberPosted 11 years agoI use a wear tool as a rough guide, then when that says it’s toast, I check with a long steel rule and replace at 0.5%
I get about 4 chains to a cassette and two or three cassettes to a set of chain rings. I did hear an interesting theory that the most useful thing a chain lube does is fill the voids to stop water and grit getting in. My chain after today’s ride as just been rinsed in the sink and is now drying on the radiator.
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