Getting Chain Length Right

Peloton Cafe - Getting Chain Length Right 1
Peloton Cafe – Getting Chain Length Right 1
By?Bike Tart?(Twitter?@BikeTart) Be it putting a new bike together or carrying out some much needed maintenance on your current machine, getting your chain length right is key – too long and it’ll slap around, not only being excessively noisy but also risking damage to your frame; but too short and it’ll be overly tight and generate excessive, accelerated wear. ?But how to get it right? ?Here’s a few simple steps? There’s various methods of how to do this bit, but I find this one by far and away the most simple and accurate. ?Wrap your chain around the small chainring, feed it around the cassette and through the rear mech (be sure to get the direction right if you have a directional chain like a 7900 series Dura-Ace chain) and then hold the ends together. What you’re looking for is the position of the jockey wheels in relation to how the bottom line of the chain runs – if the line of the chain is too close to the jockey wheels the chain is too long. ?Too far away (remembering you’re in the smallest sprocket and chainring) and there’s already too much tension on the rear mech for it to work across the whole cassette.
Peloton Cafe - Getting Chain Length Right 2
Peloton Cafe – Getting Chain Length Right 2
In the pic above the chain is basically running across itself at the jockey wheels – this will be noisy, slow to shift and will accelerate wear on the chain. ?Pull each end of the chain together until you have identified the point where the chain isn’t touching the jockey wheels, but also isn’t tugging the rear mech down too far.
Peloton Cafe - Getting Chain Length Right 3
Peloton Cafe – Getting Chain Length Right 3
This pic shows as far as you need to go. ?Any more than this and you risk your new chain being too short which will prevent it working properly across the whole cassette and will mean it not lasting as long as it should. Be sure to break the chain in the right manner depending on whether you’re using a joining pin (which requires an outer plate and inner plate of the chain to mate up for the join) or a ‘quick link’ style join (which requires two inner plates to mate to each end of the quick link). ?Also make sure you’re using the right tools for the right chain width if you are using a joining pin (particularly for 11-speed Campagnolo chains). The acid test that the chain length is right is that when you shift to the big ring at the front and keep the chain in the smallest cog on the cassette the jockey wheels should basically sit vertically above each other – a few degrees either way and you’re fine, but watch for excessive stretch in the derailleur (the bottom jockey wheel too far towards the chainrings Vs the top one) as this will cause problems. One last thing: ?if you’re changing your chain there’s a good chance your cassette should be changed too. ?They wear together, and putting a new chain on an old cassette will create indexing and shifting problems. ?One way to lengthen the life of both (if you can afford to, and be bothered to) is to have a couple of chains on rotation – perhaps have one chain soaking to clean whilst the other is on the bike? but I don’t practice what I’m preaching so don’t feel bad if you can’t or don’t want to do this!

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