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3x11. What is the reality on compatible cranks.

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3x11. What is the reality on compatible cranks.

Old 12-27-17, 10:49 AM
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KaisoArt
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3x11. What is the reality on compatible cranks.

I'd like to set up a 3x11. Assuming a SLX 11-speed RD and cassette. Which cranks would be compatible. Shimano's compatibility PDF says only FC-M9000 & FC-M8000. Is that true? I'm reading differing opinions on the interwebs. Some say that though the chains have gotten narrower, the tooth space between chain plates remains the same. (3/32" I think) This would suggest that older Deore 9 or 10 speed cranks would work? If that is not the case, the FC-m8000 is 40/30/22. Are there Deore chainrings available with more teeth? Say 48, 39?

This is for a recumbent, so it has a long chain line.

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Old 12-27-17, 11:28 AM
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That last line is key. It gives a lot of possible info but nothing specific yet.


I suspect the reason that Shimano says what they do is they assume you'll be using the SLX shifters and ft der. Shimano is very consertive in what they say will work and I kind of agree, sometimes.


What shifters and ft der will you be using? Mountain bike cranks have had their rings slightly further apart then road cranks (in the Shimano line) over the years. So when mixing cranks and ft ders keeping the der's stroke matched with the rings' spacing is important, especially if you're using a shifter without any trim functions. The shifter also needs to be matched with the der as road and mountain ft shifters pull slightly different amounts of cable per shift. While there are work arounds sort of and ranges of tolerance of this or that starting with a system that all is designed to work harmoniously is a good plan. For every kludged together system that is claimed to work perfectly there's many more that don't.


So back to those shifters. If you're using Grip Shift and the ft is not indexed then a lot of options open up as the need for best ring spacing, compatible der stroke per index click is eliminated.


The long chain run is both a blessing as well as a curse. Andy (who rode an Avatar back when for a couple of years)
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Old 12-27-17, 03:01 PM
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You are not forced to use a SLX FD and FD shifter just because you use a SLX RD and RD shifter, but I think it sounds reasonable to keep comparability between FD shifter, FD and crank in mind.
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Old 12-27-17, 03:10 PM
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11 speed chains will work on almost any crank. The issue is how well the various combinations of shifters and front derailleurs work with each other and match the chainring diameters.
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Old 12-28-17, 10:20 AM
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Originally Posted by Andrew R Stewart View Post
That last line is key. It gives a lot of possible info but nothing specific yet.


I suspect the reason that Shimano says what they do is they assume you'll be using the SLX shifters and ft der. Shimano is very consertive in what they say will work and I kind of agree, sometimes.


What shifters and ft der will you be using? Mountain bike cranks have had their rings slightly further apart then road cranks (in the Shimano line) over the years. So when mixing cranks and ft ders keeping the der's stroke matched with the rings' spacing is important, especially if you're using a shifter without any trim functions. The shifter also needs to be matched with the der as road and mountain ft shifters pull slightly different amounts of cable per shift. While there are work arounds sort of and ranges of tolerance of this or that starting with a system that all is designed to work harmoniously is a good plan. For every kludged together system that is claimed to work perfectly there's many more that don't.


So back to those shifters. If you're using Grip Shift and the ft is not indexed then a lot of options open up as the need for best ring spacing, compatible der stroke per index click is eliminated.


The long chain run is both a blessing as well as a curse. Andy (who rode an Avatar back when for a couple of years)
I'm planning to use 11-speed bar ends for MTN bike. These. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I was also planing to use Shimano SLX RD. however that is listed as 1x11 and 2x11 (GS) but only 3x10 (SGS) I think what I need is 11-speed long cage. (sgs)

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Old 12-28-17, 10:44 AM
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the space between the 2 outer chain ring teeth , which is the crank arm spider arms, may be thinner

as the chain required to fit in that closer spaced cog cluster on the back wheel, requires ..

Its not perhaps a deal breaker since a carefully done front shift , on a recumbent its out in front of you,

should not fall in between the chainrings , especially the current ramped and pinned ones.. so ... any triple crank..



New Efneo GTRO Crank , ( revue in #59 in recumbent magazine) is a triple , gear box crank
28t 1st + 2 0verdrive gears , chainrings turning faster than the crank arms as if a 40 & 50t..
chain does not shift off the chainring,,






....
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Old 12-28-17, 12:35 PM
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Originally Posted by fietsbob View Post
the space between the 2 outer chain ring teeth , which is the crank arm spider arms, may be thinner

as the chain required to fit in that closer spaced cog cluster on the back wheel, requires ..

Its not perhaps a deal breaker since a carefully done front shift , on a recumbent its out in front of you,

should not fall in between the chainrings , especially the current ramped and pinned ones.. so ... any triple crank..



New Efneo GTRO Crank , ( revue in #59 in recumbent magazine) is a triple , gear box crank
28t 1st + 2 0verdrive gears , chainrings turning faster than the crank arms as if a 40 & 50t..
chain does not shift off the chainring,,
We don't have to guess. Campy 11 is minorly closer, Shimano 11 is minorly wider. Both work, as does standard spacing.
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Old 12-28-17, 12:44 PM
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measuring is just not done much on this forum.
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Old 12-28-17, 01:59 PM
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Originally Posted by KaisoArt View Post
I'm planning to use 11-speed bar ends for MTN bike. These. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I was also planing to use Shimano SLX RD. however that is listed as 1x11 and 2x11 (GS) but only 3x10 (SGS) I think what I need is 11-speed long cage. (sgs)
Rear derailleurs do not care about what is going on with the front derailleur. If you are using bar end shifters for your front derailleur, you can do anything you want with the rear. Shimano's listings never thought about the setup you wish to use, the 2x11 (GS) that Shimano is talking about is about shifters that they offer. If that rear derailleur wraps enough chain for your setup, it won't care about what is going on with the front derailleur
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Old 12-28-17, 06:19 PM
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Well, it seems that my ignorance has cost me. I purchased a SLX m7000 which is only available as GS. This RD has a capacity of 41T. My cassette is 34/11, and my current cheapo cranks that are 48/39/28. ((34-11)=23 + (48-28)=20) = 43T Assuming this is correct, it means I need a SGS RD and will have to step up the XT 8000 SGS which has a capacity of 47T
Any thoughts/suggestions or do i finally have it correct?
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Old 12-28-17, 06:59 PM
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Well I think your math and understanding is correct but...


It is well known that the rear der's chain wrap spec compared to actual gear range can be fudged a bit IF the rider is able to handle minor technique changes. The chain length needs to be set by the large/large combo. When shifting into the small/small combo if the chain wrap capacity of the der isn't enough the chain will droop. So the change in technique is to not use the small/small or the small ring with the rear cogs which allow for droop.


On a road bike avoiding these combos is relatively easy, and if one should shift into a chain droop combo not much bad happens but chain run noise. On a mountain trail things can sometimes be less avoidable but as long as all there is "wrong" is a bit of droop things will be fine.


I would not suggest this for a customer if I were providing the parts. But for someone who already has the parts i'd say "try it out" Andy
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Old 12-28-17, 11:04 PM
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I've seen recumbents with an extra sprung derailleur cage mounted on the frame to take up extra chain slack. Could that be done here?
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Old 12-29-17, 12:19 AM
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With barcons the shift spacing doesn't matter much and with a recumbent it seems likely the chain line will not be a problem.

You're right about the RD though, the GS version is for 1x and 2x setups and knuckles are quite a bit different to follow the huge cassette. The SGS is for triples. Here's the M6000 versions, GS on the left. I don't think either of these has the wrap to do a triple with an 11-speed MTB cassette.

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Old 12-29-17, 10:33 PM
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Ok. Thanks for the replies. I'm going with an XT SGS RD and returning the SLX. The math suggests it will work. Still waiting for a few items. (I'm also going to swap out the draggy $12 tire at the same time) I'll post back if/when it all come together.
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