[Closed] Rear Mech - which?

The SLX M7000 rear mechs seem pretty good. Fitted one to my mtb recently (along with an M7000 shifter)

SLX is fine tbh, the jockeys ime aren't quite as good but they still last well and you can get replacements for £10 if you need to. Mostly I find mechs die when I smash them off a thing so it's not worth stressing over

Cage length depends on your exact setup

Im a zee mech person because of its low profile. FR version works with 10 or 11 speed with a 34 up front.

OK I've been holding out for the 'Black Friday' deals, and as it stands 10 speed XT has gone up in price at all retailers 😆

Will 11 speed XT mech work with 10 speed drivetrain? Or am I better waiting for Black Friday 'sales' to finish, and getting 10 speed XT then when they come back down in price?

Ta

I think I saw SLX long cage on offer with CRC for a reasonable wedge in the last week or so.

http://www.chainreactioncycles.com/shimano-slx-m7000-10-speed-rear-derailleur/rp-prod148232?gs=1&utm_source=google&utm_term=&utm_campaign=Chain+Reaction-UK-PLA-PLA-All-DT-SE-Shopping+QLB+Product+Desktop&utm_medium=base&utm_content=mkwid|sdllV6np0_dc|pcrid|161850334074|pkw||pmt||prd|540636UK

Medium is pretty cheap too.

That's pretty good, but XT quite a bit lighter.

Still struggling to find out if you can run 11 speed mech on 10 speed?

Still struggling to find out if you can run 11 speed mech on 10 speed?

pull ratios are different between 11 and 10 speed mechs.

If you read the thread up there though it says the pull ratio is determined by the lever not the mech. Makes sense too, a mech is just a fancy spring

Think I will go for XT 11 speed from Merlin

That does seem to be a good price. Tempted to get one myself in case I go to an 11-46 cassette, as I'm pretty sure my old XT will draw the line at that.

Yes 11 works fine with 10 speed shifter. I thought about it and as the mech is only a spring loaded device to go from a-b, as long as the distance it can move is the same and the upper jockey will clear the largest sprocket (b screw can move it enough), then it should work fine. The shifter controls how much it moves/how much cable is pulled.

I bought an 11 speed xt mech a while ago for my 10. It's been perfect with my 11-40 setup

as long as the distance it can move is the same

The shifter controls how much it moves/how much cable is pulled

The shifter controls how much cable is pulled, that's true, but the mech ratio controls how this is translated into lateral movement of the jockey wheel, and this [u]isn't[/u] the same for 10 and 11spd mechs, so your statement isn't quite true...

it's all here http://blog.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/

If you run a 10 shifter with a 11 mech then it'll undershift slightly, (which may well still be okay in reality). Cable pull on a 10 shifter is 3.4 and the mech ratio on a 11 mech is 1.1, so the mech will move 3.4 x 1.1 = 3.74mm per shift, which is slightly less than the sprocket pitch for a 10spd cassette of 3.95mm. In my experience Shimano (factory) setups overshift a tad, so undershifting may actually improve things.

If you run a 10 shifter with a 11 mech then it'll undershift slightly, (which may well still be okay in reality). Cable pull on a 10 shifter is 3.4 and the mech ratio on a 11 mech is 1.1, so the mech will move 3.4 x 1.1 = 3.74mm per shift, which is slightly less than the sprocket pitch for a 10spd cassette of 3.95mm. In my experience Shimano (factory) setups overshift a tad, so undershifting may actually improve things.

So, if i'm getting this right, and you set the mech to be bang-on in the middle of the cassette, then the worst case is 5x(3.95-3.74mm) = 1.05mm short at one end of the cassette. This will be noticeable, won't it? 😕

I suppose although the shifter is pulling the same amount of cable, it doesn't necessarily mean the mech is moving that amount, which is what I didn't take into account. Fortunately it's not noticeable and in fact it works better than the 10s mech as I'm using a larger than 36 sprocket 🙂

So, if i'm getting this right, and you set the mech to be bang-on in the middle of the cassette, then the worst case is 5x(3.95-3.74mm) = 1.05mm short at one end of the cassette. This will be noticeable, won't it?

You do have it right. According to the number sit undershifts by 0.2mm each shift, which is 1mm over 5 shifts (or 6 sprockets).

But it doesn't appear to be a problem in reality, given the anecdotal reports that it works okay..

I've not done the 10shifter-11mech thing myself so I can't confirm it either way.