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I will be putting road drop bars on one of my mtb's for this coming winter as a project that has Shimano 10 speed 1x Deore. My goal is to "simply" have road shift levers and hydraulic brakes with good shifting and braking performance. Here is my setup can some tech cyclist help me figure out my cheapest options? All the different leverage ratios for 10 speed across mountain and road (and now GRX) gets quite confusing. I would like to stay 10sp. Thanks !!! Here is the bike and I have 5 other (1 road, 2 gravel, 2 other fs mtb's currently built up with too many frames to count) so this is going to be my only e-bike: https://www.marinbikes.com/bikes/20-nail-trail-e1

Current Setup:

  • SHIFT LEVER: Shimano Deore 10sp
  • DERAILLEUR REAR: Shimano Deore Shadow Plus 10-Speed
  • CASSETTE: SunRace 10-Speed, 11-46T (I would like to be able to have that large of a cassette still)
  • BRAKES: Shimano BR-MT201 Hydraulic Disc, 203mm Rotor
Jim
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    That's not easy and going to be expensive. Have you considered buying a gravel bike with extra wide tyre clearance? – gschenk Sep 05 '20 at 08:27
  • Thanks, I actually have one of those already. This is a fairly expensive mtb that I just want to convert for winter months until the snow clears. – Jim Sep 05 '20 at 20:38
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    Why would any one be willing to sacrifice a £3000 ebike for a project and look for the cheapest options converting it to something it was never designed to be ? Just spend half the original value and buy a gravel / cx bike. – Dan K Sep 06 '20 at 05:30
  • As mentioned it will be a winter project for riding it on the road and as also mentioned, I already have 2 mechanical gravel bikes built. Not sacrificing anything I will put back the mtb set when the snow clears. Here in the Colorado Rockies trails here are mostly covered. May not have been designed to do it but e-mtb's used for gravel work just fine. I suppose I could spend more and buy an e-gravel bike. – Jim Sep 06 '20 at 07:27
  • So after research and thanks to everyone that helped here; it looks like I can just go with Tiagra 4700 hydro road levers with a flat mount to post mount adapter for the calipers and switch to 160mm rotors. Add drop bars and maybe cheap carbon fork or keep the lockout suspension fork on there. Then add a GRX400 rear derailleur and maybe a longer b-screw and goatLink. – Jim Sep 06 '20 at 07:43
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    @Jim Plugging Shimano road hydro levers into mountain calipers usually is fine so there's no need to give up the big rotors. However, there's no non-shifting left lever for those, and if that RD can be made to clear a 46, it will be at the expense of good shifting. It's intended only for 36. – Nathan Knutson Sep 06 '20 at 14:47
  • Thanks Nathan, great help ! So research seems to indicate RD-RX812 GRX 11sp rear derailleur works great with Tiagra 4700 levers,10 speed chain and cassette and that gets me to 42max which helps makes the fudge to 46 maybe possible. But I am wondering if any of the shimano mtb 11sp stuff has the same cable pull ratio as the shimano 11sp road stuff (you see where I am going.) I was wondering if Shimano finally decided to eliminate all the confusion by standardizing the ratios across 11sp road and mtb drivetrains. – Jim Sep 06 '20 at 22:16
  • Btw, in case anyone wonders why I am doing this is because it is fun ! I spent some time reverse engineering di2 11sp to make my own small/ergonomic/super sealed/ remote buttons because the climbing switches were so unnecessarily large and not waterproof. Also given the fact Shim built a wonderful electronic system with lousy options for aux switches like Sram has. Why ? again...... – Jim Sep 06 '20 at 22:25
  • So as it turns out yes, GRX 800 RD-RX812 GRX 11sp rear derailleur works with XT 11-46T cassette. So, since it has been tested and works with 10 speed drivetrain as well*. I should be able to get it to cover 46t in the 10speed and save even more money on the build. – Jim Sep 06 '20 at 23:52
  • Here is the build I am talking about: Also, I now i know shimano mtb 11 speed derailleurs have a different cable pull than the road 11 speed including GRX. But, if you take a xt plate and pulleys and move it to the grx rear d you even easier clear 46t. https://bikepacking.com/bikes/corvid-cycles-map/ Here is the reference for RD-RX812 GRX with Tiagra 4700 10 sp levers.
    • https://www.youtube.com/watch?v=LulHM6fueVU
     – Jim Sep 07 '20 at 00:16
  • Btw, they did not do this mod on the bike above with the XT 46t cassette, turned out it did not need it. https://www.facebook.com/watch/?v=727469104375415&extid=DtFEHaupmPoJLo43 – Jim Sep 07 '20 at 01:10

6 Answers6

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The only road shifter compatible with a Shimano 10 mountain RD is the Microshift BS-M10.

If you went BS-M10 you could use TRP Hylex brakes to stay hydro.

A number of bikes have been released with those exact components with Shimano 1x10 or 2x10 mountain drivetrains. It works fine if you're amenable to bar ends.

Other than the above, to get 1x10 with brifters and hydro and re-use your RD, all the options are seriously contrived, like buying the 1x11 hydro GRX STIs only to also buy a Jtek for them. Apex 1ing the bike will be cheaper.

Nathan Knutson
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    +1 On the proposed setup of BS-10 bar-end shifter and Deore 10-speed rear derailleur. I've been using it for 2 years with no issues. I run mechanical disc levers though, so no comments on TRP Hylex brakes; they seem like the only hydraulic single speed road option available though. – Grigory Rechistov Sep 05 '20 at 16:51
  • Thanks, more great info ! I had read about BS-10 shifters in a previous post but thought not an option because they weren't hydraulic. Have the TRP's on my old carbon 29 ht frame I converted to Di2 gravel ultegra gravel bike pre GRX (drilled out the cable stops). They don't have the stopping power for this bike though more than the cable pull hydraulics can provide. Wow, I have not used a Jtek in many years. I hated my old Ultegra or Dura Ace levers always breaking so I went to Campy's that I would just replace the gspring every couple of years. I need to research Apex I don't know what it is. – Jim Sep 05 '20 at 21:03
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    @Jim Apex is SRAM’s 1x gravel groupset. – MaplePanda Sep 05 '20 at 23:41
  • Thanks I will check it out ! – Jim Sep 06 '20 at 00:06
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Hydraulic brake levers and brake calipers are in general not interchangable.

Shimano MTB 10 speed rear derailleurs do not work with road levers.

You already encountered GRX. It has a 2x10 option, RX400. The rear derailleur is not designed for 1x, however, it has a clutch (Shadow+) and is rated to 46t. I expect it will work well enough in a 1x set up.

Also check chain line. The MTB has the chainring mounted further to the right. For the low gears (many teeth) the chain might have to angle far to the left.

Check brake caliper compatibility with your frame. GRX calipers are attached with the flat mount standard. Adapters for flat mount brakes to mount on IS ir post mount frames have been designed already. The adapters may be hard to find and pricey though.

gschenk
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  • Thanks great help I will definitely look more into GRX RX400 10sp option. I had been thinking it might be easiest. I have no idea which mount standard this new bike is I will need to do the research. I would have hoped when road hydraulic levers came along they would have gone with mtb standard. Obviously not though. What makes this more complicated would be the 203mm rotors I would like to keep and not have to switch them out also. – Jim Sep 05 '20 at 20:51
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    Caliper mount standard question: https://bicycles.stackexchange.com/q/44161/30402 – gschenk Sep 05 '20 at 21:31
  • Thanks I was just brain dead, it is standard post mount so I would use a flat mount adapter for GRX calipers but I will bet they only go up to 160mm. So my 203 and even a 180 rotor for that heavy bike are toast. https://singletrackworld.com/forum/topic/post-mount-frame-to-flat-mount-disc-adaptor-now-exists/ – Jim Sep 06 '20 at 00:33
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    The constraint "it should remain 10 speed" makes it difficult to find a solution that fits your brake requirements. 11 speed drivetrains offer more options because as there are post mount calipers. For instance in SRAM 1x groups – gschenk Sep 06 '20 at 08:40
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Thanks to everyone's great help here is the solution that seems like it would work out for me, yrmv (remember this is just a theoretical setup.) Want to stay with as much as OE as I can since just winter setup, 10sp 4700 tiagra levers (same shim 11 sp road cable pull ratios including grx so can't just use any rear derailleur even though is 10sp that gets complicated see # in references and other threads.), splice in xt calipers to the levers (same cost as going with flat mount to post mount adapters which are freakin 40 bucks each.) Use a GRX RD-RX812 11 sp max 42t rear d. Will handle =~ 46t in many setups' and as scene* seems to shift fine as a 10sp d. Why Shim does not make things compatible across mtb and road anymore since 9 or 10 speed I forget when they were. If Shim hydraulic 11 speed road levers worked with mtb stuff, why have GRX$ ? Same reason gravel frames slowly are getting more clearance. They are mountain bikes hardtail frames are mostly with drop bars that Tomac use to race in the 90s (we started doing it in the 80s). https://roadbikeaction.com/the-origins-of-fat-tires-drop-bars/ That is pretty much it. All of the documentation and references are in the comments from all the help and research above. *

More supporting references: https://bikepacking.com/bikes/corvid-cycles-map/

https://www.facebook.com/watch/?v=727469104375415&extid=DtFEHaupmPoJLo43

http://blog.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/

Jim
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Given the exorbitant price of brifters with hydraulic brake control, I will use the left master of Shimano mt200MT200/BR-MT201 Lever instead (cheap 60$ on aliexpress for pair). I replaced the lever on the master with a home-made one that could take the end of a steel brake cable. The other end will of course be connected to the brake lever of the mechanical brifter. I already know that Giant does a similar thing with their Conduct mechanical to hydraulic converter. Trying to get it is unobtonium. So I make myself one.

Ted Hohl
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stromeur
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There are two problems in your plan.

Firstly, it's almost impossible to find road drop levers for hydraulic brakes without shifters. Thus you're stuck with levers that have integrated shifters.

Secondly, in their infinite wisdom, Shimano has made road levers incompatible with the cable pull ratio needed by MTB rear derailleurs. Thus, if you select a lever with shifter, it's not going to be compatible.

Normally, in situations like this I would recommend bar-end shifters and brake levers without shifters. The bar-end shifters are compatible with practically anything, especially in the front (also in the rear too if you stick with friction shifting). However, I doubt there is a bar-end shifter compatible with 10 speed MTB rear derailleur cable pull ratio -- they are usually made for road ratios. Also, finding hydraulic road drop levers without shifters is going to be a challenge.

In theory, some bar-end shifters allow friction shifting in the rear after turning a switch. However, in practice, you probably won't want to be shifting all the time this way.

It unfortunately seems the DIY market is not well catered for in today's environment, and you would need to change so many parts of your bike that the conversion is not going to be cheap.

The situation was entirely different when I converted a 3x8 speed hybrid bike to a 2x8 speed drop bar bike. It had V brakes (fortunately road drop levers are available for the V brake cable pull ratio), and the 8 speed Ultegra bar-end shifters worked perfectly, as 8-speed road and 8-speed MTB cable pull ratio is the same (with the exception of some old Dura-Ace parts).

juhist
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    Hello, and welcome to 2020. There is a market for third party adapters for solving problems exactly like this. One example: http://www.jtekengineering.com/shiftmate/shiftmate-compatibility-charts-choices/ – ojs Sep 05 '20 at 09:31
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    @ojs Oh but no, these products cost more than a reasonably priced rear derailleur! Why would one purchase such a product instead of merely replacing the rear derailleur? – juhist Sep 05 '20 at 09:35
  • The reasons I would buy one are are for building combinations that manufacturer doesn't support (like the OP is asking about) and using an existing irreasonably priced rear derailleur. It also costs less than a single GP5000 and you don't seem to have a problem putting the money into consumables that have a very marginal benefit. – ojs Sep 05 '20 at 09:38
  • As far as I know the only road-hydraulic 10 speed group is GRX RX400. Its derailleur costs 50€$£ or less. It has all the features of previous decade's 10 speed MTB derailleurs (11-43 capacity, clutch). Why bother with a bodge? – gschenk Sep 05 '20 at 12:09
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    @gschenk Tiagra 4700 is hydraulic as well. – MaplePanda Sep 05 '20 at 19:01
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    ...and the Tiagra 4700 derailleur is cheaper than the GRX derailleur (the Tiagra 4700 derailleur is the derailleur I consider "reasonably priced"). But however, its cable pull ratio is the same as for 11 speeds so you cannot combine a random 10-speed derailleur with the Tiagra levers. – juhist Sep 05 '20 at 19:23
  • Good lord just priced the 10sp GRX400 stuff, Tiagra 4700 looking like the solution I will use and just get the flat mount adapter for the brakes to my post mount frame. I can always just go with the GRX400 rear D in this case and not break the bank. At least can still use my 10sp 46t speed sunrace cassette. Thanks for all the help ! – Jim Sep 06 '20 at 00:43
  • Used a jtek for years back-in-the-day with Campy rebuildable levers on my shimano groupset. With the solution you guys helped me with above don't really need to do that and downgrade shifting a little bit (Or at least it used to 10+ years ago.) – Jim Sep 06 '20 at 07:54
  • And....TRP make singlespeed hydrauilic levers. Absolutely mass market. – Noise Jul 01 '21 at 18:10
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Tiagra 4700 has the same cable pull as 11s. All other 10s drop bar levers have the old cable pull, which is the same as 10s MTB gears. 105 5700? Ultegra 6600, 6700? Maybe not with hydraulic brakes, which I would have preferred as well, but there really are good mechanical disc brakes. Or you build your own transfer system to actuate a hydraulic cylinder mounted on the bars… :-) Yes, I'm a tinkerer, but it is a cheap and easy way to get a simple yet effective 1×10 road bike from stray parts.

48×11-40 ≈ 50/34×11,5-28 : short cage wide cassette.

46×11-36 ≈ 50/34×12×27 : tighter gears, not giving up much. : light & tight for a racey build.

46×11-40 ≈ 50/34×12-29,5 : Fast & light enough for any road use with plenty of headroom, still fairly nice even gearing and cadences for normal city speeds in the middle of the cassette.

Ted
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    10s Shimano Road and Mountain are normally said to be different and incompatible with each other? – Swifty Jul 01 '21 at 16:12