Monday, June 21, 2010

Chains are cheap

As far back as I can remember it's been a maxim for cyclists - when you replace a chain, replace your cassette as well. I don't remember where I first heard it but it was almost certainly some time back in the 1980s when I was racing. It was just one of those things we did without thinking and it never occurred to me until now to question it.

The chain on my Bianchi was coming up to the 6000km mark this week (thanks BikeJournal for the reminder) and my handy Park chain gauge was telling me it was coming to the end of its useful life, which was fine because I had a replacement chain hanging in the shed, but I'm a bit short of cash to buy a new cassette. Those ten speed babies aren't cheap. What do do?

When I thought about it, does the new chain-new cassette maxim make sense? The theory seems to go that a new set will mesh nicely together and that a worn cassette will wear a new chain more quickly. But is that going to be as much the case in the modern era of ten speed kit as it was in the five and six speed days, or more so, or what?

The cassette on the Bianchi looked fine so I threw caution to the wind and put a new chain on. After brisk 30km trial ride, all seems well. The gears are shifting fine and after a few minor adjustments of tension screws, the drivetrain is even quieter than normal. (I prefer the superb Connex chains, the connecting link makes installation and removal infinitely easier than the infernal Shimano non-reusable pins)

Sitting down to write this post, I checked around to see what others did, and Google revealed a wide range of practices, from a change of cluster every two chains, to even longer service intervals. Myth busted, and it looks like I'll save some money from hereon in to boot.

2393km so far this year.


Unknown said...

Thanks Dave. My chain has done about 4,500km and is close to its use date. Went to replace recently and was also going to replace seven-speed cassette and the three-speed front rings. Then realised the rings were fixed to the cranks! Would have involved a whole new crank set. Decided to leave as is in vain hope I can afford a new bike by Xmas.

NancyBoy said...

Nice post Dave. My experience has been that if I replace the chain somewhere between 0.75% and 1.00% stretch, the old cassette will work fine with the new chain. If you leave it go beyond 1% you'll be needing a new cassette. I've managed to get as many as 4 chains to 1 cassette. I also managed 18,000km out of one chain and cassette - however the whole shooting match was so badly worn that I had to change chain, cassette and rings in order to get a working gearset again. Ouch.... On the other hand, my fixie has just over 10,000km on the one chainring, sprocket and chain, it's hardly been cleaned and the 1/8" setup has nowhere near 0.75% stretch. I reckon there's another 10,000 in it yet.

David Killick said...

Ben, I reckon a new bike is your best bet. There aren't too many problems a new bike doesn't fix.

Nancy, the old Connex was a hair past 0.75, mind you, I've had new chains that were close to that out of the box for some unknown reason. Interesting about the fixie chain. Mind you, if you're only getting 20,000km out of them you're probably using a couple a year aren't you?