55/Rad

Building a Niner One 9 into a gravel bike and need to make decisions on drivetrain. I want to run either Shimano 10 or 11 speed road shifters with an XT rear mech and a 11-34 or 11-38 cassette.

If I run 10 speed STI's and cassette, I THINK I read that I should go with a 9 speed rear mech. Need to confirm this.

If I run 11 speed STI's and cassette, I'm not sure what MTB rear mech would work most effectively. I have a spare set of Ultegra STI's I wouldn't mind using.

Other issues I should be thinking of?

Thank you all....

55/Rad

fietsbob

Leave the Road Front derailleur on ... then .....


feeling a need for those 2 more cogs stacked on the back wheel ,
puts you in the divergent incompatibility the engineers created..


I'm old , on the Coast and very trend monger resistant ,

55/Rad

I'm pushing 60 and currently sitting in a home overlooking the ocean in Yachats.

I don't need the extra gears. Could easily go with 9. It's just that I have a set of DA 10 speed STI's and Ultegra 11's sitting around and figured I'd use one of them.

jimc101

On the basis you are going to buy new

10 speed, your limited to Tiagra (4700, expect this to be replaced later this year) which you can do 11-34 out the box

For older 10 speed (5700/6700) you can fit a M591 RD, which is a pretty universal RD for what it can take.

11 spped, R7000 and R8000, again you can do 11-34 out the box, and have a clutch RD (RX800). Since MTB Dyna-SYS started at the 10 speed level there has been no compatibility between MTB and Road shifters and RD's

Going to 11-38 your be looking at road-links/similar to add the the RD capacity, as you can get 11-34 out the box, thinking that going for a CX/subcompact at the front would probably be a better option.

You say you have a spare set Ultegra STI's, without knowing the series, these are ignored, but slot them into the above.

55/Rad

Thanks Jim - the Ultegra series I have is 6800.

jimc101

The 6800 STI's should have no issues working with an 11-34 cassette (CS-R8000) you will need a medium cage RD. or the clutch as noted above.

fietsbob

71 .. last year ..

Small house by the Columbia..







....

DrIsotope

RX800 GS + 11-34 cassette = plug-and-play, no fiddling or adapters. Maybe 38T or a 40T narrow-wide up front, depending on your terrain? And the RD is clutched, so even better. Hook the unused front shifter up to a dropper and you're cruisin'.