Learned the hard way that chain length isn't just about big-big

Had a shop vet in Portland tell me to always check chain length on the big-big combo plus two links. Ignored him on a gravel build last month and the chain was too slack in the small-small, dropped off twice on a descent. Anyone else had shifting issues from not double-checking chain wrap?

3 comments

3 Comments

lindag332d ago

Nah, I've been fine just checking big-big plus two every time.

quinna892d ago

Oh man, that big-big plus two rule is solid. I read a piece from a mechanic over at BikeRadar a while back that said most people get chain length wrong because they only check big-big and forget about slack in small-small. He said the chain wrap difference can be huge on 1x setups or wide-range cassettes. Dropping the chain on a descent is sketchy, I've seen it happen to a buddy on loose gravel and it snapped his derailleur hanger. Always worth taking the extra minute to run the chain through the small-small and see how much droop you've got.

wadew512d ago

@quinna89 you're dead right about that small-small droop check being the real tell. Exact same thing bit me on a gravel rig last spring. Built it up, chain looked fine in big-big, went out for a shakedown ride, and the chain was flapping like a jump rope in the little gears. Almost ate dirt on a fast loose turn when it fell off. The wrap difference on wide range cassettes is no joke. That plus two rule from the shop vet in Portland is solid gold. I check both extremes now every time I size a chain. Takes an extra two minutes but saves a lot of hassle on the trail.