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How do YOU Determine Chain Length
All,
Just a curiosity question really.
I've used 2 methods and have recently learned of a couple more.
1. Count the number of links on the old chain. Nice and easy as long as you can count without using fingers and thumbs.
2. Chain over largest cog and largest chainring and through derailleur. Pull tight, then release by 1 whole link's worth.
New ones to me....
3. As 2 but don't run through the derailleur. Not sure how this works because the extra length of chain to run through the derailleur is a fair few links. Maybe it takes account of the fact that you should never run big/big.
4. Chain over smallest cog and smallest chainwheel and through derailleur. Pull tight until the upper jockey wheel is about half inch above the lower run of the chain. Respected mechanic showed me this way this afternoon.
Anyway, interested to know how and why you do it.
Darren
Just a curiosity question really.
I've used 2 methods and have recently learned of a couple more.
1. Count the number of links on the old chain. Nice and easy as long as you can count without using fingers and thumbs.
2. Chain over largest cog and largest chainring and through derailleur. Pull tight, then release by 1 whole link's worth.
New ones to me....
3. As 2 but don't run through the derailleur. Not sure how this works because the extra length of chain to run through the derailleur is a fair few links. Maybe it takes account of the fact that you should never run big/big.
4. Chain over smallest cog and smallest chainwheel and through derailleur. Pull tight until the upper jockey wheel is about half inch above the lower run of the chain. Respected mechanic showed me this way this afternoon.
Anyway, interested to know how and why you do it.
Darren
Comments
Park Tools recommended method is your no.3 and add a whole link (inner and outer). I find this too inaccurate due to different cage lengths.
The old shimano method is the one I use. Chain over biggest chain wheel and smallest cog and routed through the derailleur. When connected the axis between the two jockey wheel axels should be verticle. I ALWAYS use a speed link and leave what I estimate to be a link too long just in case. You can always remove one more link but it's bad practice to try to re-introduce a chain rivet, although I've done this as well in the past!
FWIW I always use KMC chains and speed links as I've seen too many shimano chains come apart, probably from badly installed sacrificial rivets.
I'm sure I'll get shot down in flames.
Richard
Method 3 could be a bit dodgy if you've got a rear derailleur with those extra large jockey wheels. It would probably need a further extra link.
I've tended to use method 2 on a new build because it works directly on the only critical measurement. Too short a chain on Big/Big and you're gonna break something...
When just replacing a chain (of the right length) I remove the old chain, lay it on the ground and match up the new chain to the old chain and cut to the same length.
Shaun