Is my chain now too short?
- Thread starter stormed
- Start date
glpinxit
Retro Guru
As I was saying earlier, Sheldon says:
"The best technique for setting chain length is to thread the chain onto the large/large combination, without running it through the rear derailer. Mesh the two ends on to the large chainwheel so that one complete link (one inch, -- one inner and one outer half-link) overlaps. In almost all cases, this will give the optimum length."
http://sheldonbrown.com/derailer-adjustment.html#chain
"The best technique for setting chain length is to thread the chain onto the large/large combination, without running it through the rear derailer. Mesh the two ends on to the large chainwheel so that one complete link (one inch, -- one inner and one outer half-link) overlaps. In almost all cases, this will give the optimum length."
http://sheldonbrown.com/derailer-adjustment.html#chain
Sheldon's remark is exactly what is written in Shimano's instructions.
BUT...
For road bikes with short chainstays the bottom pulley is often very close to the chainring and this gives a really acute sideways line of the chain. In really extreme cases it will derail when pedalling backwards. If it runs quietly I'd say OK, but if rattly then adding a link won't do any harm.
BUT...
For road bikes with short chainstays the bottom pulley is often very close to the chainring and this gives a really acute sideways line of the chain. In really extreme cases it will derail when pedalling backwards. If it runs quietly I'd say OK, but if rattly then adding a link won't do any harm.
S1m0nR
Old School Hero
Re:
For what it's worth, it looks like you should add an extra pair of links to that chain. With the increased length it will still enable you to select small/small without the chain fouling on the forward (top) derailleur sprocket.
Whilst the big/big setup you've currently got seems to work, you're running at the limits of the derailleur's travel which may increase wear and decrease reliability.
Your bike though!
For what it's worth, it looks like you should add an extra pair of links to that chain. With the increased length it will still enable you to select small/small without the chain fouling on the forward (top) derailleur sprocket.
Whilst the big/big setup you've currently got seems to work, you're running at the limits of the derailleur's travel which may increase wear and decrease reliability.
Your bike though!
Just to add to my last post.
Shimanos current official method is shortest chain possible. Which is nice for long cage mechs with lots of wrap, and systems with large ranges, 22/32/44 chainrings, 11/32 cassette for instance, as you are unlikely to be in that gear, and unlikely to suddenly change to a larger cassette. It's also best from a complexity point of view to just have one method across all groupsets, to avoid confusing people. Especially as the chains are common.
Once you get to short cage mechs with minimal wrap, close ratio cassettes and 10-14 tooth difference doubles, the longest chain possible method is better, as the cage will tend to be nearer vertical during more of the riding you do, and under significanty less load (both from the spring, and side loading) instead of under nearly full tension. You can also drop a bigger cassette in, training wheel/road racing/neutral service wheel for instance, instead of your "normal" TT wheel with a corn cob cassette on it, without exploding your rear mech.
Two methods, small/small with the right chain length to *just* have some tension from the cage. Alternatively, big small (53x11 for instance) with the rear mech cage as near to vertical as you can. (IIRC this was the old shimano road/Suntour method, may have been campag as well)
This almost certainly WON'T work on an MTB/Touring triple. Use big/big for that.
Shimanos current official method is shortest chain possible. Which is nice for long cage mechs with lots of wrap, and systems with large ranges, 22/32/44 chainrings, 11/32 cassette for instance, as you are unlikely to be in that gear, and unlikely to suddenly change to a larger cassette. It's also best from a complexity point of view to just have one method across all groupsets, to avoid confusing people. Especially as the chains are common.
Once you get to short cage mechs with minimal wrap, close ratio cassettes and 10-14 tooth difference doubles, the longest chain possible method is better, as the cage will tend to be nearer vertical during more of the riding you do, and under significanty less load (both from the spring, and side loading) instead of under nearly full tension. You can also drop a bigger cassette in, training wheel/road racing/neutral service wheel for instance, instead of your "normal" TT wheel with a corn cob cassette on it, without exploding your rear mech.
Two methods, small/small with the right chain length to *just* have some tension from the cage. Alternatively, big small (53x11 for instance) with the rear mech cage as near to vertical as you can. (IIRC this was the old shimano road/Suntour method, may have been campag as well)
This almost certainly WON'T work on an MTB/Touring triple. Use big/big for that.
