Gear Ratios

[Bro Derek]

The cheapest way would be to get an old shimano 9 speed MTB rear derailleur and an 11-36 10 speed cassette

Shimano 9 speed MTB RDs have the same cable pull ratio as Shimano 10 speed STis and can comfortable accommodate the gears

Neither will be expensive or require much fiddling

[Mongoose!]

8 hours ago, Bro Derek said:

The cheapest way would be to get an old shimano 9 speed MTB rear derailleur and an 11-36 10 speed cassette

Shimano 9 speed MTB RDs have the same cable pull ratio as Shimano 10 speed STis and can comfortable accommodate the gears

Neither will be expensive or require much fiddling

Just be careful as not all Shimano 10 speed road shifters share the same pull ratio.

external cable ( 5600 and 666 series) differs from 5700 and 6700 series.

4700 (newer Tiagra) = same ratio as 11 speed

[NotSoBigBen]

2 hours ago, Mongoose! said:

Just be careful as not all Shimano 10 speed road shifters share the same pull ratio.

external cable ( 5600 and 666 series) differs from 5700 and 6700 series.

4700 (newer Tiagra) = same ratio as 11 speed

You never too old to learn I guess but I understood that was true to an extent for 10sp front dérailleurs but not rear?

I have found this a good reference when trying to work out what works with what, and I do a fair amount of that!

https://en.wikibooks.org/wiki/Bicycles/Maintenance_and_Repair/Gear-changing_Dimensions

My suggestion would be a decent 9sp (XT/XTR) MTB derailleur with an 11-36 cassette as suggested by the Bro above

Edited October 2, 2025 by NotSoBigBen

[johnpf]

Thank you everybody

When I get home I will be hounding my Local Bike Shop