Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: slope on 01 October, 2023, 02:00:51 pm
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What are the supposed benefits of Shimano clutched rear mechs? Are they advantageous at all on a 1 X 10 set up?
Does the panel think a non clutched 9 speed Deore RD-M592 would stretch to run on a 10 speed 11-36 cassette?
(according to my FBI/007 type investigatin', the indexed cable pull is the same on Shimano Deore 9 speed and my 10 speed SL-BS79 olden days road bar end shifters)
https://winstanleysbikes.co.uk/shimano-deore-shadow-rd-m592-rear-derailleur (https://winstanleysbikes.co.uk/shimano-deore-shadow-rd-m592-rear-derailleur)
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Yes, I have the same setup except it’s a 11-34 cassette that I have. It works fine.
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It’s compatible with a 36t cog on cassette. The only thing 10 speed changes is spacing between cogs. I run the mech on my recumbent without issue.
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I've not noticed any particular issues using a 9sp Deore M591 (non-clutched) with 10 sp cassette (tho it's 11-34t), even doing some pretty rough ridgeway sections. Bear in mind that the Deore M592 has no barrel adjuster on the actual derailleur AFAIA - a feature which I like, on the M591.
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I use an inline barrel adjuster, though I do mostly have the rear set to friction in which case it’s irrelevant
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I just like to eyeball the mech alignment with the cassette sprockets as I'm adjusting/ turning the BA, but yes whatever works.
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Which you only need to do for indexed gearing
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Thanks folks for the replies, most helpful :thumbsup:
Rather than go down the Shiftmate No.6 with a 10 speed RD-M6000, 10 speed 11-36 cassette and my oldie but lovely, 10 speed SL-BS79 bar end shifter (which will be a thumb shifter anyway courtesy of the VO bracket I also have) . . .
. . . I shall order a RD-M592, now knowing it will cover a 10 speed cassette and index with my ^ gear lever
(the SL-BS79 has a barrel adjuster, so should be ok for tweeks on that front - quite why there isn't one on the actual RD-M592 rear derailleur is annoying? - or perhaps that's just old skool, move on and get real mate philosophy?)
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Which you only need to do for indexed gearing
Indeed. Just meant in context of OP with indexing bar ends.
I also have some SL-BS79 BEs on the shelf in case I feel the urge - yes pity they don't have a friction option. Have an 80s Gitane with friction DT shifters - still good to use, on the rare occasions I ride it.
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DUH!
The solution - a real deal right hand only actual thumbshifter 10 speed and friction for Shimano pull 10 speed MTB rear mech :thumbsup:
https://www.sjscycles.co.uk/gear-shifters/microshift-slm10r-10-speed-thumb-shifter-right-hand/
Never thought to look to see if there was such a thing ::-)
(with thanks to Winders over on the CTC forum)
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why not go for the dedicated mtb 10sp trigger shifter which is superior ergonomically and costs peanuts?
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why not go for the dedicated mtb 10sp trigger shifter which is superior ergonomically and costs peanuts?
That's what's on the bike and its ergonomics really don't suit this awkward? fella - whereas I have thumbie brackets on my other bikes which make me very happy :)
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i see. interesting :)
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On the question of benefits of a clutched RD, I find that I need it on my 1x11 Surly Trucker, with its long chainstays and small (40T) front ring. On the other hand, on my 2x11 gravel bike, with shorter chainstays, I don't notice any benefit.
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Likewise, I’ve never had a problem with non-clutch whilst riding MTB, CX and gravel bikes. I have a GRX clutch rear mech and have never bothered to engage the clutch. Perhaps it is more advantageous for 1 x set ups, but from my perspective they are a solution looking for a problem.
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Clutch mechs are mostly about avoiding chain slap off-road
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Likewise, I’ve never had a problem with non-clutch whilst riding MTB, CX and gravel bikes. I have a GRX clutch rear mech and have never bothered to engage the clutch. Perhaps it is more advantageous for 1 x set ups, but from my perspective they are a solution looking for a problem.
Ignorant question - is the clutch manual?
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Ignorant question - is the clutch manual?
There’s a lever on the side of the mech that engages / disengages it.
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The clutch is a thing to prevent the chain coming off the front chainwheel under extreme vibration in off-road conditions.
In a normal road mech, one purpose of the arm on the rear mech is to act as a chain tensioner, to take up the slack as the chain length required changes as you shift gears.
It is spring-loaded, and gives and takes chain length readily.
Off-road, this does not work so well. As the bike bounces around, the arm will flap forward and back easily. As it flaps forward, the lower run of chain will become slack, increasing the risk of the chain dropping off the front chainring.
The clutch is a friction device on the rear mech.
It will not allow the arm to move forward easily.
So the arm will not bounce forward in response to a bump, and create slack chain.
But it will move forward in response to the force created by a gear change.
The clutch only operates on forward motion of the arm: it will resist giving out slack, but it will move backwards taking up slack instantly.
It has no real purpose on road mechs.
It can be dis-engaged using a lever on the mech.
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Thanks to you both for the explanation.
I suppose I was thinking of non-tarmac road e.g. Roubaix
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The clutch is a thing to prevent the chain coming off the front chainwheel under extreme vibration in off-road conditions.
In a normal road mech, one purpose of the arm on the rear mech is to act as a chain tensioner, to take up the slack as the chain length required changes as you shift gears.
It is spring-loaded, and gives and takes chain length readily.
Off-road, this does not work so well. As the bike bounces around, the arm will flap forward and back easily. As it flaps forward, the lower run of chain will become slack, increasing the risk of the chain dropping off the front chainring.
The clutch is a friction device on the rear mech.
It will not allow the arm to move forward easily.
So the arm will not bounce forward in response to a bump, and create slack chain.
But it will move forward in response to the force created by a gear change.
The clutch only operates on forward motion of the arm: it will resist giving out slack, but it will move backwards taking up slack instantly.
It has no real purpose on road mechs.
It can be dis-engaged using a lever on the mech.
So what's the point in disengaging it?
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So what's the point in disengaging it?
The extra friction in the chain tensioner adds noticeable resistance to shifting to a bigger cog/chainring. With the clutch enabled shifts are slower and adjusting the drive train so every shift works smoothly is harder.
The amount of friction is adjustable so instead of turning it off you can try turning it down, but that is of course yet another variable to fiddle with if things are misbehaving.
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So what's the point in disengaging it?
Its a lot easier to remove the rear wheel with it disengaged, otherwise you have to fight the clutch in addition to the spring.
SRAM clutches dont have a switch, instead you push/force the cage forward and there is a pin that can hold them there. Its actually very helpful and something that would be good on other models.