Chain compatability

[chris]

Lewis my eleven year old son had a day off school yesterday due to a teacher drinking training day. We decided to go mountain biking in the woods and whilst getting ready he asked what was in my repair kit that I carry with me. After showing him the contents he picked up the spare bit of chain that I carry with me and asked me if we could use it to mend the chain on all of our bikes. Its a very good question and I'm not sure what the answer is, I'd always assumed that it would mend all of our chains. All of our bikes are 6/7/8/9 speed and all use SRAM chains with PC followed by a number stamped on the side plate. So can anyone tell me the answer?

[Gus]

8 speed links are too wide for 9 speed but do work if you are desperate and as a last option.

[Biggsy]

6, 7 and 8 speed chains are about the same width - exactly the same in some case - and interchangeable.

9-speed chains are narrower overall, and 9-speed sprockets are closer together.  8-speed is too wide to work properly (or quietly at least) with a 9-speed cassette.

The "PC" numbers on SRAM chains are model numbers.  You can tell the speed by looking them up on the web, etc.

You don't need to carry spare links of chain for a derailleur-geared bike on a ride, though.  A faulty link (or pair of links) can be removed and the bike ridden with the chain shorter than usual.  The rider would just need to take extra care to avoid using the largest chainring and largest rear sprocket at the same time.  The chain would be too short for that combination but long enough for all the others.

However, I would recommend carrying a couple of pairs of Powerlinks (one 8-speed, one 9-speed) as these make joining a chain really quick and easy (when you know how to use them).  Of course you still need a chain tool as well for breaking the chain.

[chris]

You don't need to carry spare links of chain for a derailleur-geared bike on a ride, though.  

We have two tandems and a triplet in our fleet, so that's four timing chains, and I have two tool kits, one for 26" wheels and one for 700c. I can't be bothered to change the contents of the tool kit each time I go for a ride, I just grab the appropriate tool kit and go.

[Greenbank]

You don't need to carry spare links of chain for a derailleur-geared bike on a ride, though.  

We have two tandems and a triplet in our fleet, so that's four timing chains,

Are the timing chains the same type of chain as the drive train? (i.e. could you borrow a link or two from the drive train to fix a timing chain problem? Although that's obviously more hassle than just carrying a few spare links of chain.

[chris]

Are the timing chains the same type of chain as the drive train? (i.e. could you borrow a link or two from the drive train to fix a timing chain problem? Although that's obviously more hassle than just carrying a few spare links of chain.

Yes they are all SRAM of one type or another, so in theory I could borrow a link, but I don't have a problem carrying a spare length of chain.

Incidently, I did a 50 mile charity ride on the triplet in aid of the local cancer hospice with the kids today, and about 15 miles into it, whilst we were honking up a hill, a link in the main chain broke, and as the chain dropped onto the road it got caught in the spokes. We had a bit of a wobbly moment as I unclipped, but we were able to stop without further drama. We walked up the hill to a farm gate and inspected the damage, the wheel was OK, but the chain had cut into the side wall of the rear tyre and there was a very large bulge that I think would have blown out if we had ridden further. Luckily we were carrying a folding spare so I changed the tyre and inserted a new link into the chain. Twenty minutes and two very dirty hands later we were on our way again.