Broke My Chain. Bugger.

jamesco

Hi guys, I managed to snap my chain last night (due to the amazing power of my legs I'd like to think, though more likely caused by dreadful maintenance) and having just put on a replacement I've got a quick question: the new chain came with 116 links; on the smallest front and rear cogs it was too long for any tension, so I took two links out (i.e. two of the dogbones) and it's just under tension now on the smallest cogs while also going up to the big cogs. Is that generally good enough or is there some kind of rule for how many links/tension there should be? Foolishly, I didn't count the links on the old chain before throwing it away, as I was getting funny looks walking around central London swinging a chain

Cheers, James.

whyamihere

Run it big to big. Shorten the chain until the rear mech's fully stretched out.

AllTheGear

The chain should probably be shorter than you have it.

Break the chain, run it round the biggest cog on the cassette, and the biggest chainring, without going through the rear mech, and pull tight. Then add 2 links (one inner link+one outer link, rounding up slightly if it's not exact) Then cut the chain down there and thread it through the mechs and join.

This feels like it's going to be too short, but works out right. I guess the idea is the chain needs to be as short as will work, becuase it will 'stretch' over its life.

This procedure is for SRAM road drivetrains but should be the same for all?

Edit: whyamihere's suggestion sounds at least as sensible as it takes rear mech position into account, I just followed my instructions ;-)

jamesco

No sooner asked than answered Thanks!

scoobers

Mine also broke at the weekend, sheering off the rear mech and jamming it between the frame and the rear wheel. It's cracked the carbon frame, buckled the wheel and bent the mech.

Soul Boy

Damn Scoobers, now thats bad luck!!! Have you stopped crying?

scoobers

Soul Boy wrote:

Damn Scoobers, now thats bad luck!!! Have you stopped crying?

Only just, it was a Planet X SL Carbon with 260 miles on it.
Pretty gutted.

Soul Boy

You have my deepest sympathy, that was one hell of a piece of kit....

bratboy

The Campy method is as you have described - small to small then take up the slack until the rear mech under tension and there is no chain rub.

The Shimano way is small cog to big ring, then when the two jockey wheels of the rear mech are align in a vertial plan you have the right tension.

And allthegear has descibe SRAM procedure.

Which ever method you choose what you need to do is make sure that you don't have chain rub when going small to small and don't over stretch it.

But don't forget you shouldn't run the chain small to small or big to big unless really unavoidable as it produces very poor chain alignment which results in inefficient power transfer and excessive waer.

Hope that helps.