We are about to go on a tour on the tandem - checked the chains and the rear is over 1% worn but not by a lot. The bike has a rohloff and runs a tensioner.
Will the chain be weaker? IE should I replace it for reliability? I fear the chainring and sprocket will be worn to the chain so would need replacing as well and I don't really have time to get the parts, fit them and test ride it. especially as I run a 37 tooth chainring
A stretched chan just means the rollers are worn. That in itself won't make it weaker. Being well used might mean it is worn elsewhere but I doubt it'll make much difference. I usually run drivetrains into the ground, never had any issues
How did you meansure?
If its with a chain checker, try with the steel rule method (1/8" over 12" is dead)
But saying that, if it's only *just* over and you are running (effectively) single speed, so no side loads, you should be fine for a good while longer.
Oh, and no, the chain won't be weaker until the inner plates start cutting into the pins. So a shit load more than 1%. How ever you measure it.
Ta - thats what I thought but was having a panic. Last night I started assembling a spares kit and got carried away and was about to put my entire spares collection in the trailer!- I will be carrying a few spare links and missing links just in case.
I took the chain off my Alfine bike recently to clean it properly as I ran out of wet lube and have switched to dry.
It is very stretched and a bit noisy but it doesn't matter on a single cog setup, however I did notice that the parts marked as 4 on the diagram below have been worn away and are now closer to a C shape rather than O's!
It still runs fine but I think this is the point where the strength of the chain becomes doubtful, so I think the time has come to splash some cash.
I don't use the chain checker anymore, I think its a false economy (all my chains are well past the measuring limits of the chain checker except my newest bike (which with 300 miles on it, I suspect would also show as borderline on the checker!)
aye - 4 is the bit that actually wears and alters the length of the chain. rollers wear as well but don't add to the length ( but chain checkers do measure the wear in rollers as well)
the chain is not worn to the point of being all floppy and bendy yet.
Of course it is weaker. What you ask is that will it be fine for your trip, I'd say ride on soldier. 🙂
Yes, it will be weaker, but at this point you have a choice between riding down the front of the bathtub curve, or up the back of it. I'd probably go with the latter.
When I have had a worn chain fall to bits, I have noticed wear on the pins (1 in the handy diagram above) as well as the inner plate swaged bits.
But when chains fail on me, it is by the join between pins and outer plates (1 and 5) bursting open. Never seen a snapped pin or burst inner plate. Maybe wear in the pin/inner plate join means that the inner plate can flex more, which enables it to exert leverage against the insides of the outer plates, which adds stress to the riveted join. Or maybe it is something completely different.
Just guessing but maybe of more influence would be how much it's been 'cross chained' ie big-big. As it's a Rohloff, probably nowt to worry about.
With my Rohloff I run till the sprocket is dead, the chain is irrelevant as it's always outlasted the sprocket. Change both of them at the same time, change or reverse the chainwheel as required. You can reverse the sprocket but I never do as it's pretty worn by the time I change it and you end up running what may be now quite a pitted surface against the seals.