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I currently ride a single speed belt Soma Wolverine with road bars, hydraulic disc brakes and I love it. Only trouble is my knees are telling me I need some lower gears especially up the hills. That's 55:22, 175mm crank, 700c-28 wheels - About 69 gear inches? Go to a 50-tooth front ring sure, but then I would go spin out even sooner down hills. I want to keep it simple, I have tried Alfine 11 and did not like it (leaks make the clean belt drive dirty, big heavy hub on the back wheel), do not have the money for Rohloff. Looks like a 1x11 setup is for me.

SRAM has 1x11 group sets that will do the trick. But SRAM is uncommon - never seen it on my bike trail in Melbourne - and discounts are far less common.

With other big two, fair chance of picking up discounts on random 11-speed stuff. So question is - what makes a 1x11 groupset special? Is there any reason not to pick up a heavily discounted Ultegra spider, a third-party 42T ring, a Deore XT 11-42 cassette, matching XT derailleur and matching brakes/shift levers?

The issue could be that moving from one extreme to another the chainlink is just a whole lot wider and the chainline way more bent than it might be designed for. Do 1x11 groupsets have any design features to deal with this? Do you need a chain designed to flex to allow for this worse chainline? I have no issues building wheels/changing bottom brackets to make this work.

Update: 1x11 is not so hard! Here's what worked for me.

Brakes: This is the driver for a lot of decisions. Wanted drop bars, hydraulic brakes and lever shifting. All brands have options but I chose Shimano Dura Ace levers and calipers, based on available deals. Also as mentioned much easier to build the whole kit with compatible, discounted parts. Unfortunately the Dura Ace calipers will not work on my IS-mount frame because there just is NO flat<->IS adapter as there is for many other combinations. They're put away for the next frame.

Crankset: Dura Ace FC-R9100. Again, the big discount tempted me and it's really pretty - functionally probably no better than Ultegra. And I can sell the two rings it came with.

Front ring: Wolf Tooth 110 BCD Asymmetric 4-Bolt 38T, with their special chainring bolts - very nice, hex key on both sides! "Rides of Japan" on youtube showed a 1x11 conversion with this ring and Di2 system. Teeth are thick/thin alternating. You do have to file away a small part of one mount to fit it on modern Shimano cranks but is a small job, Wolf Tooth even explain this and the video shows it too.

Chain: SRAM PC1170. Comes with a special one-time link that makes joining pretty easy.

Rear cassette: SRAM PG1170 11-36 - very wide range, mid-price. I think the 42T would not work on the GS derailleur.

Rear derailleur: Shimano Ultegra RD-RX800. I worried about this because Shimano say this derailleur is good for a maximum 34 teeth but it handles 36 OK with plenty of adjustment left. Nicely made! This is the "GS" medium cage model with a clutch, so with the clutch engaged it will apply extra tension and stop the chain from slapping around over bumps.

Downshift cable hanger: A Wolverine frame has downtube shifter braze-ons. I needed to find one right-side cable hanger to make the gearshift cable run, or else I would have needed a full-length cable sheath.

Brakes: Going to use some Shimano M675 SLX calipers Was going to use some M675 SLX callipers but bleeding them I found one is leaking from the cracked ceramic piston and spares are not sold. Used for maybe 6 months commuting. Disappointing quality again, Shimano. Will now be using TRP Hylex (original) calipers with the with the Dura Ace levers. Have found people in forums successfully mixing Shimano calipers with Hylex levers so no problems anticipated.

Outcome: 11 gears between 27-91 inches. Both higher and lower than I had. Shifting is smooth.

  • I switched from Shimano 2x10 (50/36T) to SRAM 1x11 (48T). You need to get the shifters, chainring (if you need to), derailleur and cassette (11-36). The left shifter didn't need to be replaced because there's no FD, but I replaced it anyway. I got no issue getting them done in Brisbane, so shouldn't be a problem Melbourne. – imel96 Nov 13 '18 at 5:10
  • Not sure how you'd know how common SRAM is on the trails you ride. I certainly can't identify the groupset of a passing bike. – David Richerby Nov 13 '18 at 10:13
  • @DavidRicherby of the ones I can see climbing stairs, at lights etc. it's pretty much all Shimano. Saw one SRAM bike once. More Campy actually. – Adam Eberbach Nov 13 '18 at 22:19
  • Shimano say this derailleur is good for a maximum 34 teeth but it handles 36 OK with plenty of adjustment left. That's typical for Shimano. If they say it will work with something, it will work. Which means you can normally push somewhat beyond what they say "works". – Andrew Henle Dec 3 '18 at 10:32
  • @AndrewHenle Hmm. Initially. I hate the way they cleverly build a life span into their products. Have had some very disappointing Shimano failures - Alfine 11 leaky hub is one. – Adam Eberbach Dec 9 '18 at 21:51
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SRAM have emphasized the 1x configuration, but 1x systems can be built from Shimano components too.

You are right that a 1x system is pretty much a wide ratio cassette and a single front ring. Double-wide chainrings are commonly used to help chain retention as there is no front derailleur cage to guide the chain. Clutch derailleurs are also used to tame chain slap on rougher trails encountered when gravel riding.

You can use a double crankset with a single ring on it, but it's a hack and as you say you will have cross-chaining problems. Dedicated 1x cranks align the ring with the middle of the cassette so the chain deflection is minimized.

You will not be able to use a XT MTB derailleur with a road drop bar shifter. Shimano MTB and road 11 speed use different derailleur actuation ratios (see here) so MTB derailleurs and road shifters are incompatible. The largest cassette that Shimano long cage road derailleurs can take is 11-34, but, if you are coming from single speed that is going to feel like a huge ratio range.

  • Thanks! Great information - I have seen 42T cassette single with road levers on youtube but since that was all Di2 I guess the road levers mixed with MTB derailleur without issues. Looks like the Ultegra GS medium derailleur's limits will decide much of the direction here. – Adam Eberbach Nov 13 '18 at 3:09
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    Shimano MTB 11 speed RDs can be used with drop bar shifters using a Wolftooth Tanpan or Jtek ShiftMate pull ratio adapters. Also, Di2 XT can be used with Di2 road levers in 1x mode. – Klaster_1 Dec 3 '18 at 2:59
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    Wolf also makes a derailleur hanger extension that allows you to use large rear cogs with Road Derailluers. Doesn't fix the capacity problem, but does solve the clearance one. The extended hangers work really well. – Fred the Magic Wonder Dog Dec 10 '18 at 18:28
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The place to start is the gear range you want and how close you want the ratios to be. I am a roadie riding a 50/34 compact coupled to a 12/30 10 speed cassette. The range is good for my riding, though if I made a change it would be to have a 32 on the rear. If I went to a 1x I might use 46 in the front because the cassettes go to 11 and I don't need 50/11. That would say I want 40 in the rear to get the same range as I have now or 42 to match the 32 I would like. I have about 13 different gears, so going to 11 would mean some gaps get larger. I notice the big gaps on my current setup but they are not so bad. The trade is the convenience and (maybe) cost of a 1x versus the narrower spacing of 2x. You have to decide what works for you.

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