Backward <-> Forward Compatibility Dilemma

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FireDog46

Hi It's been a long time since I last rode with purpose. This summer I finally dusted off the old Rocky Mountain ETS-X and got back into it. I quickly realized one hell of a lot has changed. Some I like - Most seems more for the benefit of the corporate bottom line. The one that truly intrigues me is the development Eleven Speed (Twelve Speed just around the corner). I always ran 1x9. The problem is, if you are a climber, that last large cog is just not big enough, AND, if you are a spinner, those close ratios are just not quite close enough. So, I started researching upgrading to 1x11. My wallet hit the wall on the cost for a new rear derailleur. The cassette and shifter are manageable. I would be getting a CS-HG800 11-34T cassette. The shifter would be the basic SLX. For the derailleur I am at a loss. This is what I would like to do and hope some one might have answer: I have an older XTR RD950: NOS I bought some time ago. I've mounted it and is working well with a 9sp 12-36T cassette. Does this derailleur have enough adjustment to allow it to reach the 34T on a 11sp 11-34T? That's really my only question. I've already checked with HALO and my wheel and hub are 11sp MTN compatible. #1 · Aug 1, 2018 Hi It's been a long time since I last rode with purpose. This summer I finally dusted off the old Rocky Mountain ETS-X and got back into it. I quickly realized one hell of a lot has changed. Some I like - Most seems more for the benefit of the corporate bottom line. The one that truly intrigues me is the development Eleven Speed (Twelve Speed just around the corner). I always ran 1x9. The problem is, if you are a climber, that last large cog is just not big enough, AND, if you are a spinner, those close ratios are just not quite close enough. So, I started researching upgrading to 1x11. My wallet hit the wall on the cost for a new rear derailleur. The cassette and shifter are manageable. I would be getting a CS-HG800 11-34T cassette. The shifter would be the basic SLX. For the derailleur I am at a loss. This is what I would like to do and hope some one might have answer: I have an older XTR RD950: NOS I bought some time ago. I've mounted it and is working well with a 9sp 12-36T cassette. Does this derailleur have enough adjustment to allow it to reach the 34T on a 11sp 11-34T? That's really my only question. I've already checked with HALO and my wheel and hub are 11sp MTN compatible. See less See more Sort by Oldest first Oldest first Newest first Most reactions #2 · Aug 1, 2018 The older XTR RD won't work with an 11spd shifter. With 10spd Shimano introduced Dyna Sys, different cable pull and they also changed the RD pull ratio which matters to you. Art's Cyclery Blog » Science Behind the Magic | Drivetrain Compatibility 12 speed has been out for a while, now it's even available on the SRAM NX level. 11-50 for NX and 10-50 for GX. An 11-34 with a single chainring is going to be super limiting. "Upgrade kits" are pretty cheap (RD, chain, cassette, shifter). #3 · Aug 1, 2018 So many things seem confused in this post.

12spd isn't "around the corner". It's been out a while now unless you're only talking Shimano. It's called SRAM Eagle.
11spd rear derailleurs aren't all that expensive @ ~$50 (what's expensive is relative, I suppose)
Unless I've missed something, that road cassette won't work with a mtb freehub. The 11spd road cassettes are wider and the spacing is different than 11spd MTN. It may be possible, but I'm guessing not.
HollyBoni already pointed out that 8spd doesn't play nice with 11spd.

#4 · Aug 1, 2018 Slow down and clarify some things... 1: is an 11s 11-34 really what you want? That's less range than you have now, and is sold as a road bike cassette. I do not believe it will fit on your hub - which is compatible with mountain cassettes (11-42 and larger). Your m950 derailleur will not work with any 11s shifter; the pull ratio is different. 2: Cost of derailleurs. A M7000 SLX retails for $55, XT goes for $65-70. It's hard for me to understand how you're ok with the cost of the other parts but not that. #5 · Aug 1, 2018 Looking at the spider design I think the 34T cog was big enough so they could push it closer towards the spokes like they do on 40T+ cassettes. The Shimano website says that it's compatible with MTB and road hubs, and that you need a spacer on road hubs. https://bike.shimano.com/en-US/product/component/ultegra-r8000/CS-HG800-11.html #6 · Aug 1, 2018 Unfortunately it still won't work with the rest of the drivetrain Shimano 11spd road cassette = 3.69mm between cogs Shimano/SRAM 11spd mountain cassette = 3.9mm between cogs #7 · Aug 1, 2018 That part in the Arts Cyclery article I don't understand, i'm not sure if it's correct. SRAM sells their 1x road stuff with mountain cassettes. I have a Rival 1 that came with an XG-1150 from the factory as a groupset and it works great. What's up with that? Lot's of people also run 11-40/11-42 cassettes with road stuff and a Wolftooth Roadlink. Although one thing I forgot is that on Shadow (and +) RDs Shimano now specifices not just the max low sprocket but the minimum low sprocket too, which for example on an M8000-GS XT is 40T. Show more replies 1 Reply #9 · Aug 2, 2018 Thanks for all the replies. I thought my simple query might get lost in all the other noise. One thing I have done is "my research" and quickly realized there is a ton of misinformation out there. The Arts Cyclery article is a case on point. Read it with a very large grain of salt. Here's a link you will find interesting: 2018-2019 SHIMANO Product Information Web consider it the "horse's mouth" for Shimano. Trying to reduce the cost of any upgrade is only part of my quest. The new derailleurs introduce a level of complexity I don't need. The CS-HG800-11 11-34 will both fit my freehub and the capacity of my M950 XTR derailleur. But will it "reach" that eleventh cog. (Shimano hasn't changed their MTN shifter pull ratios) I'm tight for cash - hoping someone might have tried this. When I get the cash I will be trying this - will post back. Final note - I'm too old to be taking chances in the mountains. An Eleven Speed 11-34 cassette is the perfect range and distribution. #10 · Aug 2, 2018

FireDog46 said: The new derailleurs introduce a level of complexity I don't need. Click to expand...

Well, they're just as easy to install and adjust as your old RD, and they won't flap around unlike your old RD.

FireDog46 said: (Shimano hasn't changed their MTN shifter pull ratios) Click to expand...

They did change the shifter cable pull and derailleur pull ratio, you will find this out the hard way after installing everything. After that, you will look at 11spd RDs, and realise Shimano specifices a "Low sprocket_Min." as 40T, then you can throw out that 11-34 cassette too if you want decent shifting. Maybe also message some companies that make cable pull adapters because apparently they are wasting their time.

FireDog46 said: An Eleven Speed 11-34 cassette is the perfect range and distribution. Click to expand...

It is, if your idea of a climb is a speed bump. Good luck.

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