So I've got a gravel bike with a sram force 11 speed hydraulic brake/shifter, which is currently being used with a sram apex rear derailleur. After constant problems with the apex derailleur not shifting into higher gears (weak spring appears to be the cause as I've changed to fresh cables multiple times), I want to swap it out.
I've never got on with sram road/gravel shifting however did like 11 speed GX. Am I wrong in thinking that I could just put an 11 speed GX mech on instead of another apex or rival derailleur? As the derailleur is essentially "dumb", could I even put a GRX 11 speed derailleur on as it's the shifter that sets the leverage ratio?
Thanks for any help.
Jtek Shiftmate 9 could be worth a look if your theory doesn't pan out...
http://www.jtekengineering.com/shiftmate/shiftmate-compatibility-charts-choices/
Shifter's pull ratio need ro match the mexh. But the "feel" of the shifting will be 90% defined by the shifter, so not sure the swap will make enough of a difference for you, even if it did work
I assume the Apex is made of the same mince as SX?
Bloke in bike shop told me the reason my SX mech utterly fails to work across the whole cassette is down to some spring that's missing or not up to it compared to NX, GX, etc. He said you could retro fit this part but may as well just replace the mech. I will be doing, with Shimano as he said 12sp Shimano works with Sram.
If Apex (SX) is the same then you could just go Rival (NX?) for ease? I had Rival on an old bike and it work well enough. Don't think the 11sp Shimano stuff plays with 11sp Sram?
as it’s the shifter that sets the leverage ratio
That's not how it works.
The shifter pulls through a given amount of cable. The derailleur moves proportionally to that cable pull - different derailleurs might move by different amounts for the same amount of cable pull.
I don't think SRAM/Shimano Road 11 will play well.
I don’t think SRAM/Shimano Road 11 will play well.
That said, according to http://blog.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/ the shift ratio is 1.3 vs 1.4, so it'll probably "work", but badly - 10% difference to cassette pitch, so for a 11 speed cassette, I'd expect at least one terrible gear index.
Looks like you could use a SRAM 10 speed mtb derailleur without any problems, though.
Why not just buy a Force rear mech, better quality than Rival etc so should work better.
