Chain length

ilovegrace

Hi all
I am changing my 105 10 speed medium cage rear mech to a Ultegra short cage , I have recently renewed the chain.
When I fit the new mech from medium to short cage will I need to adjust the chain length and if so by how many links ?
Thanks in anticipation of your help.
regards
Mark

drlodge

Yes you will likely need to shorten it, by how much you will only know once new mech is in place and you size the chain.

shirley_basso

Shouldn't make a difference.

I simply run the chain around the big ring at the front and big cog at the back then add 2 links for good measure.

keef66

You'll probably be able to run the chain without shortening it, but for maximum neatness / weight saving you could lop off a link or possibly two.

If you're joining it with a missing link it's simple enough to remove a link at a time. Each time make sure the big / big combo is not going to wreck your rear mech if you somehow end up selecting it..

drlodge

It will make a difference...short cage mech has less wrap than a medium.

Simple answer is...swap the mech and see if the chain needs shortening.

Most go with the big-big + 2 links type method. Personally I prefer to put the chain on through the derailleur, place it on small-small and shorten the chain so its as 'long as possible' with some spring tension in the RD.

ilovegrace

Hi Chaps
Many thanks for your replies.
Mech should be here by the weekend , so i will give it a try with the methods recommended.
Thanks again
regards
ILG

StillGoing

drlodge wrote:

It will make a difference...short cage mech has less wrap than a medium.

Simple answer is...swap the mech and see if the chain needs shortening.

Most go with the big-big + 2 links type method. Personally I prefer to put the chain on through the derailleur, place it on small-small and shorten the chain so its as 'long as possible' with some spring tension in the RD.

If standard practice is to wrap the chain big/big without the derailleur, how will it make a difference? Simple answer is it won't.

drlodge

philthy3 wrote:

If standard practice is to wrap the chain big/big without the derailleur, how will it make a difference? Simple answer is it won't.

OK, *If* the chain has been sized based on big-big *and* assuming he doesn't actually need a medium cage derailleur *and* the cassette isn't enormous (28 teeth or less), the chain should be fine. However we don't know the length of the chain, for example, it might have been sized on big-big a while back when there was a bigger cassette (32T) in place. There must have been a reason his bike came with a medium cage rear derailleur and chain could have been sized accordingly.

StillGoing

drlodge wrote:

philthy3 wrote:

If standard practice is to wrap the chain big/big without the derailleur, how will it make a difference? Simple answer is it won't.

OK, *If* the chain has been sized based on big-big *and* assuming he doesn't actually need a medium cage derailleur *and* the cassette isn't enormous (28 teeth or less), the chain should be fine. However we don't know the length of the chain, for example, it might have been sized on big-big a while back when there was a bigger cassette (32T) in place. There must have been a reason his bike came with a medium cage rear derailleur and chain could have been sized accordingly.

OK I get your thinking, but he hasn't mentioned changing the cassette.

keef66

In other news, is the new Ultegra rear mech a 10 speed model, ie 6700 or earlier?

Bottom briquettes

I tend to put the bike into biggest ring / biggest sprocket and adjust the angle of dangle so that the top jockey wheel is just clear of the biggest sprocket by about a thumb width disconnect the old chain, then feed the new chain around the drive train over the largest chainring then pull the two free ends together until there’s about an inch of movement left in the cage. Then I hold the chain ends using a chain hook tool ( or big paper clip bent into shape) in that position. Mark the links at which the join is going to happen, then remove any excess links. Join the chain, then fine tune the angle of dangle position with the b screw on the rear mech, if needs be.

ridgerider

Another vote for the 'small/small' method and make the chain as long as possible without interference with the rear mech cage.