Have a 11 speed rear mech and been offered 10 speed bar end shifters. Would this combination work or would it be a horrible mismatch?
Precis:
1. The shifter determines
cable pull – the length of cable the shifter pulls for each ‘click’. Nearly all the cable pulls are uniform for every click (exception some newer Campagnolo ergos).
2. A derailleur’s
shift ratio is the ratio of lateral movement distance of the derailleur to the cable pull. E.g. older Shimano RDs have a shift ratio of 1.7 - for every mm of cable pulled by the shifter, the derailleur will move 1.7 mm.
3.
Sprocket pitch is the distance between (centre of) top and bottom sprockets of an ‘n’ speed cassette divided by ‘n-1’ – distance the RD has to move the chain for a perfect shift from one sprocket to the next.
These three elements are related:
Cable pull x Shift ratio = Sprocket pitch
Shimano 10 Road cable pull = 2.3 Shift ratio = 1.7 Sprocket pitch = 3.95
Shimano 11 Road cable pull = 2.7 Shift ratio = 1.4 Sprocket pitch = 3.74
Shimano 10 bar-ends with Shimano 11 RD cable pull = 2.3 Shift ratio = 1.4 RD cage will move 3.2mm each click.
Mismatch, assuming both bar-ends and RD are Shimano. If a mixture, then a Shimano 11sp RD might (in theory) work with 10sp Campagnolo bar-ends and a Shimano 10sp cassette. Careful research required.
HTH
Detail:
https://www.artscyclery.com/science...ce-behind-the-magic-drivetrain-compatibility/