2k miles and no measurable chain stretch?

[MajorMantra]

I have nearly 2000 miles on my Ribble and today I decided to check the chain (10s Campag Centaur) for stretch using the 12" measuring method. I was surprised to find no measurable wear at all.

Now, I'm very light (~53kg) so obviously I put less stress on my components, but does this seem plausible? I plan to check again, maybe with a different tape/ruler, but I thought asking was worthwhile.

Cheers,
Matthew

 

[Rohloff_Brompton_Rider]

my brompton chain did 2300 miles before it needed changing and i'm heavy. but another bromptoneers who bought bikes from the same dealer got a lot less.

 

[longers]

I've got one the same and it's a 10sp Campag.

It's ready for changing now but I'll need to be intending to actually ride that bike anytime soon to get round to doing it.

 

[youngoldbloke]

Have a Ribble with 10 sp. Veloce, well over 2K miles, no appreciable wear using a Park CC3 tool (not even close to the .75 measure).

 

[SavageHoutkop]

but another bromptoneers who bought bikes from the same dealer got a lot less.

that would be me!

Mine's about 10 miles a day, started June last year; chain replaced in November, needed to have the rear sprockets changed as well as the stretch was that bad (checked with chain tool and ruler).
I think I could have got away with not changing my rear sprockets, but my husband's bike was worse (same milage, heavier/faster rider). he's now thinking that he's worn out one of his rear sprockets again (gotta love winter grit/salt combo!)

 

[Davidc]

Seems reasonable.

In my madder days I used to go through chains - but I abused them. (Best ever effort was stretching one which had done less than 100 miles racing a mate up Pebblecombe, 1 in 3 in Surrey, then stretching its replacement 3 days later while touring with him, riding up Porlock, 1 in 3 in Somerset with 30kg of camping load!). They never lasted more than 2000 miles and that was with the old 5 speed chains which were stronger than current ones.

Now, a few decades on, I couldn't do either, despite gearing giving twice the mechanical advantage, and I don't carry as much weight. Chains last between 8000 and 12000 miles (Shimano HG50 8 speed).

All I'd say is measure it every month and once it has stretched replace it before it takes the chainwheels and cassette with it. Don't rely on mileage as a guide, measure it.

The other benefit from replacing them promptly is that you help avoid the dreaded snapped chain problem.

 

[totallyfixed]

Definitely use a chain checker, one of the best investments re bike maintenance. On my fixed I check it every week and have to change the chain every 2 -3 months [more wear constant pedalling], well I don't have to but it's a lot less expensive than having to buy new sprockets.

 

[Rohloff_Brompton_Rider]

that would be me!

Mine's about 10 miles a day, started June last year; chain replaced in November, needed to have the rear sprockets changed as well as the stretch was that bad (checked with chain tool and ruler).
I think I could have got away with not changing my rear sprockets, but my husband's bike was worse (same milage, heavier/faster rider). he's now thinking that he's worn out one of his rear sprockets again (gotta love winter grit/salt combo!)

i wonder why you both go thru chains and sprockets quicker than me? i also know you maintain your bikes more often than me. i wonder if city streets have more grit and dust? i took my clock off at about 2300 miles. i reckon i've done +4k on the same sprockets. i have changed the chain since we last spoke tho and the sprockets will need changing pretty soon.

 

[GrasB]

What I tend to find with chains is there's very little measurable wear then suddenly it starts to stretch quickly. As for chain life it varies immensely depending on the weather conditions, how much climbing you're doing, how much power you're typically outputting (moving more weight at a lower power output seems to wear the chain less than less weight & more power) & even which chain you bought.

 

[MajorMantra]

Thanks for the replies. I guess I'll just keep checking it fairly frequently.

Definitely use a chain checker, one of the best investments re bike maintenance. On my fixed I check it every week and have to change the chain every 2 -3 months [more wear constant pedalling], well I don't have to but it's a lot less expensive than having to buy new sprockets.

I've looked into chain checkers but I've read lots of reports that say they can exaggerate wear or simply mislead you. In any case, a 12" ruler has got be better than a 4" checker. (Cue lecture about accuracy and precision...)

Cheers,
Matthew

 

[Davidc]

Thanks for the replies. I guess I'll just keep checking it fairly frequently.

I've looked into chain checkers but I've read lots of reports that say they can exaggerate wear or simply mislead you. In any case, a 12" ruler has got be better than a 4" checker. (Cue lecture about accuracy and precision...)

Cheers,
Matthew

What they will do, when you compare one measurement with the next, is tell you when the thing is beginning to go. What grasB says is exactly what I've noticed, and thats crucial - catch them before they can do damage or break and let you down.

I use a 6" fold up ruler and it tells me straight away when to replace with a new, and not especially expensive, one. That's probably why I've never had a chain break on me on the road!

 

[youngoldbloke]

http://www.sheldonbrown.com/chains.html

"Measuring Chain Wear

The standard way to measure chain wear is with a ruler or steel tape measure. This can be done without removing the chain from the bicycle. The normal technique is to measure a one-foot length, placing an inch mark of the ruler exactly in the middle of one rivet, then looking at the corresponding rivet 12 complete links away. On a new, unworn chain, this rivet will also line up exactly with an inch mark. With a worn chain, the rivet will be past the inch mark. This gives a direct measurement of the wear to the chain, and an indirect measurement of the wear to the sprockets:

• If the rivet is less than 1/16" past the mark, all is well.
• If the rivet is 1/16" past the mark, you should replace the chain, but the sprockets are probably undamaged.
• If the rivet is 1/8" past the mark, you have left it too long, and the sprockets (at least the favorite ones) will be too badly worn. If you replace a chain at the 1/8" point, without replacing the sprockets, it may run OK and not skip, but the worn sprockets will cause the new chain to wear much faster than it should, until it catches up with the wear state of the sprockets.
• If the rivet is past the 1/8" mark, a new chain will almost certainly skip on the worn sprockets, especially the smaller ones."

- too early in the morning for me to convert your figures to fit the above from Sheldon Brown. 12" method has the advantage you don't have to remove the chain - use a good steel rule. I find it easier to trust a Park Tool chain checker.

 

[MajorMantra]

At what length is a chain considered to be stretched ?

I carefully measured my currant chain when new at 913.5mm for 36 links. After 750 miles I now have 914.5mm. The previous chain that was scrapped along with the cassette measured in at 923mm.

I have read that a chain should be replaced before 1/16th inch for 12 links (920mm for 36 links) Do you agree with this rational ?

It would be at 1/16 - you don't replace until you've reached that figure. As far as I know this method has served people well for decades, and it's the one I plan to stick to.

Matthew

 

[andrew_s]

Use the Sheldon method for deciding whether to replace a chain.

Checkers are good for quickly showing whether you should check with a ruler, but can be pretty pessimistic. It's not unknown for a new unused chain to show as being worn out on a checker.
It's because the rollers move on the pins, and the checker checks between a roller pushed one way and one pushed the other way. Whoever made the checker has to make an assumption about how much the roller is going to move. Roller movement has no effect on chain function or wear.
The (expensive) Shimano checker is an exception, as it has a 3rd prong that allows it to check between rollers pushed the same way.