Recommendations on a 1x10 drivetrain for CX

General CX/MTB
1

I just got a new cross frame and want to build it as a 1x10. Constraints are:

  • I want to keep my 105 10sp shifters
  • I want to keep my Shimano/Sram compatible wheels
  • I want to keep my Sram force crankset.
  • I want a gearing that allows me to climb the steep pinches that are around Canberra (firetrails/singletracks), and that can also allow me to not spin out too easily. My lowest ratio at the moment on my 2x10 old cx is 34-30, and I’d like something lower.

So far my ideas are:

  • narrow wide chainring (wolf tooth or other, 38T or lower)
  • sram derailleur like the Force 1. These do not work with Shimano shifters, but can apparently be made to work with a shiftmate (in theory, the model I’d be looking at is the 6s). I’ve never worked with shiftmates so I don’t really know what to expect.
  • Cassette: will need 10 sp, but not sure what. Maybe one of those 12-36 sram cassettes? 38-36 would be equivalent to my lowest gearing on my old cx (1:1). I’d like something lower, but not sure what 10sp cassettes are around that would go over 36T, and 10 sp.

Any no-no’s with that plan? Any better ways to do it?

Thanks people.

2

No no shiftmate. Use a shimano RD.

I don’t think you can adjust the chainline at all on the Force crankset, so 1x might struggle.

3

I have 1x on a GXP/Sram Apex crank. It works fine, smooth shifting with 10 speed rear. I have multiple BB lengths on a few 1x setups and haven’t had a problem - worst case you run the NW ring on the inside of the spider.

I would echo the call for a shimano derailleur - with a narrow wide ring (i use a Wolftooth, never dropped a chain) I don’t think there’s a need for a clutched derailleur - eliminates all the extra work around stuff like shiftmates.

Do a google for the maximum gear size that you can fit in a medium or long cage 105 or Ultegra RD, as it’s often larger than the prescribed amount.

4

shiftmate seems dubious. the same 6S apparently works with 10sp road → sram 1:1 OR dynasys… that would mean that sram 10sp shifters would be compatible with dynasys mechs and v/v… which ain’t a thing AFAIK.

also, then you’d be running a shiftmate.

plenty of pro cxers running shimano and no clutch, you’ll be ok, just get a 9sp shadow mech. M772 (comes in med cage, in theory the 'gram can only handle a 34 on the cassette), M592 (long, goes to 36), M4000 (long, goes to 36, has a barrel adjuster). Leave a front mech on as a chain keeper maybe.

BSA BB = use a small shim on the DS cup to get your chainline where you want it and try both the inner and outer positions when fine tuning.

CS-M771 or PG1070 both have 11-36 options. 28-93" with a 38T ring.

5

I ran those same cranks (:’() with that same setup! Had no issues using 5700 shifters, 42t wolftooth and 9spd Saint rear mech. Never dropped a chain in about 8 months, chain line was fine with ring on the inner bolts I believe.

6

Thanks guys. I’m surprised that the shiftmate solution attracts so few punters. I guess it’s an extra complication in the system. Would be good to hear from ShiftMate users though.

Blakey, Alivio looks good and is also cheap which is great. But im not sure I want to go back to 9 sp. wolf tooth also does not recommend 9sp chains with their rings.

Also I have bad memories of using a shim between bb cups and cranks on my roadie, it started creaking very quickly. Might have used the wrong material (alu on carbon).

Lemontime these are your old cranks, im holding onto them :stuck_out_tongue:

7

10 speed chains work fine on 9 speed drivetrains.

8

I think Blakey means that if you use a Shimano MTB RD, it has to be a 9sp one. 10sp dynasys RDs won’t work with 10sp road shifters. 9sp RD with your 105 shifters will shift 10sp no worries.

9

Thanks for the clarifications lmntm and Pete. Pete you’re right I was interpreting it exactly like that.

10

There’s also 10spd Shimano XT cassettes that are 11-36t that you could use.

11

^ that. i.e. M4000 = cheap and works.

btw 9 & 10 sp chains are the same internal widths, so w/e, wolftoof are idiots.

see above, cs-m771

12

CRC got dealz on XT chain x cassette. I got one recently + 9sp rear XT mech, shifts 10sp cassette with 10sp barcons no dramas

13

Is Ian building this? Surely he shudders at the very mention of sram anything after working on my bike recently.

14

Honestly unless on a real budget sell your 105 shifters and get cheap SRAM ones and a x9 rear mech, the combo is amazing

15

Get a Shimano Saint 9spd M810 rear derailleur, they have a much stiffer spring than standard shimano derailleurs. This should work well on a 1x set up with either a narrow wide or tall tooth chainring (such as the surly stainless ones). You can even modify the spring tension if you’re keen to pull the derailleur apart.

I have the top half of a Saint derailleur you can have, you’ll have to provide your own spring, cage and pulleys. But you can pilfer these from any shimano derailleur.

You can modify the leverage on derailleurs by putting a spacer between the body of the derailleur and the cable. A 6mm spacer allows Sram 9spd shifters to pair up with 10spd Shimano. Theoretically you could do the same thing with 10spd road to 10spd mtb, but I haven’t done it, nor have heard of anyone doing it.

Shiftmate sucks.

And if you need a bigger cassette than 11-36, 1x10 probably isn’t for you.

16

^ thanks for the advice buddy, in the end I’ll decide what’s good for me.

17

No, you have to drill a hole in the arm to do that.

18

I am super keen on hearing your Ian stories.