RD-M4000 Alivio; suprisingly tough?

[Brucey]

The final generation of XT 9s MTB rear mechs (such as RD-M772) were a new design called 'shadow' (later followed by 'shadow plus') in which the cable is mounted on an arm behind the main part of the mech, that looks like it might go into the spokes, or foul the chain when running small-small but doesn't do either. These mechs have only one sprung pivot and a slant parallelogram and are arguably spiritual successors to various sun-tour mechs of old, rather than other shimano mechs.



This mech design has facility for being 'direct mounted' which appears to have been not at all popular; most of these mechs use the included hanger adaptor.

The same design features carried over into the 10s dyna-sys mechs but with a much lower shift ratio, about 1.2 (actually less than this I think) instead of 1.7.

These features also carried over into other mechs such as 9s alivio RD-M4000.



The differences with these mechs being that there is a barrel adjuster fitted and there were many more parts made from mild steel, including the inner cage plate, the cable arm, and the hanger adaptor. In the posher models these parts are often made of aluminium.

One omission on RD-M4000 is any kind of spoke barrier on the inner cage plate; in fact this mech (in common with many other current shimano models) could hardly be better designed to snag and make a 'death plunge' into the spokes and wreak the usual havoc. Best to keep tabs on the low gear stop screw adjustment.

I recently was given a very mangled RD-M4000 that had done the death plunge; "you never know, it might have some useful spares in it, ha ha". It was the most mangled mech I'd seen for a long time; the hanger adaptor was twisted by about 45 degrees and the inner cage plate was so bent that it was touching the pinch bolt. There wasn't a straight line in it.

Out of idle curiosity I had a go at straightening it; I expected the mangled parts to just snap, but to my surprise they didn't, and after a few minutes I ended up with a roughly mech-shaped mech. I had a go at a mangled SLX mech with a similar layout and that straightened up OK too. I wish I'd taken photos of them as they were; now they just look like slightly dirty mechs with a few scratches on... I suspect that a posher version might have bent a bit less but that it also might have cracked when being straightened.

So swings and roundabouts as normal then; this style of mech is more likely to finish in the spokes, bent to heck, than many, but more likely to be repairable if it does....

cheers

[Peter W]

That's very interesting.

I fitted a cheap 9 speed Alivio 12/36 cassette to my older 9 speed Spesh Roubaix, in combination with a 9 speed Deore M.T.B. rear mech, and the bikes 9 speed Sora shifters. It all works. The intriguing thing is though that the cheap Alivio sprockets are 'bendy' when levered with the blade of a screwdriver.(Metal bending - no free play in cassette.) This slightly affects the changing at times.

It changes properly over the full cassette range when changing down, i.e. from smaller sprockets to larger, because of the ramps, but is sometimes hesitant in changing back up, i.e. from the larger sprockets in particular to the next smaller one, but only over the three bigger lower gear sprockets. There is no hesitation changing across the higher geared end of the cassette where that sprockets are smaller and less bendy.

I can only assume that the bendability of the larger ones makes the chain stick, sometimes needing a double click to shift, then one back once it has. Still, at the price(18.99) I can live with it, and still be pounds in pocket even if it does wear out more quickly than a posh expensive cassette. Hell, I can buy 3 0r 4 of them for the price of a better one! I'm past caring about image!

[Brucey]

it seems unlikely that bendy sprockets affect the shifting too much/all the time because the shift will always have a chance to happen at the dead spot in the pedalling cycle, i.e. when the sprockets are not seeing any load. Not that you should be shifting under appreciable load anyway.

If the upshift shifting is a bit slow there are several possible reasons for this including;

- dodgy cables
- slight misalignment of the mech (remember there are multiple places for this setup to bend)
- worn guide pulley bushing (won't affect downshifts so badly because of pusher plate on mech)
- worn chain
- slight mismatch between shifter and sprockets (9s MTB shifters have slightly different cable pulls vs 'road' 9s shifters and 9s MTB cassettes are built with the ramp mismatch in a different place to 'road' ones)
- gear cable differently flexible vs the one intended (stiffer gear cables can affect the shift ratio in the lower gears)
- cable mounted incorrectly at the pinch bolt (eg clamp plate set in wrong orientation)

- or some combination of the above; all these things can add up because they rarely cancel one another out.

cheers

[pwa]

And back to having a barrel adjuster on the mech. TF for that.

[Peter W]

Thank you. I had wondered about that slightly different cable pull. It does sound to be the most logical factor. It was also suggested to me (as you say too) that the old outer cable (fitted new well greased inner) could also be a spoiler. I will replace that.

The issue is only a minor blip and easily compensated for when it occurs (double click and one back takes just seconds) and it's more than worth it for the supercharging effect on my well worn legs in that lower than 1 to 1 bottom gear ratio up those serious climbs! (And I do appreciate that barrel adjuster.)

[reohn2]

The only 9sp sprockets I've bent have been on XT cassettes(type with sprockets riveted to an alu spider),this was on tandems.
The cheap end HG30/50 IME are good quality solid kit,I split these cassettes to make custom ratios with some of sprockets in these cassettes ending up with the ramps out of sequence,but they still change well.

[thelawnet]

The final generation of XT 9s MTB rear mechs (such as RD-M772) were a new design called 'shadow plus' in which the cable is mounted on an arm behind the main part of the mech, that looks like it might go into the spokes, or foul the chain when running small-small but doesn't do either. These mechs have only one sprung pivot and a slant parallelogram and are arguably spiritual successors to various sun-tour mechs of old, rather than other shimano mechs.

Shadow (not Shadow Plus) was introduced across the 9-speed range in 2009/2010, as RD-M972, RD-M772, RD-M662, RD-M592.

These were all supplanted by 10-speed versions the following year with the same design.

Shadow Plus means 'Shadow plus clutch', i.e. Shadow with a clutch, rather than, say, an improved version of Shadow. This was introduced with RD-M985 in 2011, the next year to Saint & XT, but not to SLX & Deore till M7000/M6000, so no Shadow Plus 9-speed eists.

This mech design has facility for being 'direct mounted' which appears to have been not at all popular; most of these mechs use the included hanger adaptor.

It wasn't quite this, it was rather that the 'Shadow' design resulted in the B-axle moving, hence the design required an extra B2 link to connect the derailleur to the hanger. This B2 link was permanently attached to the B-axle, and the B2 link then used a bolt through the hanger in the conventional manner.

Subsequently Shimano announced direct mount, whereby the B2 link was made removable using a (very tight) bolt, and you could then bolt a 'direct mount'-type hanger through the B-axle.

As I understand it, none of the old 9-speed had removable B2-links, as they were immediately replaced with 10-speeds, however the considerably newer RD-M4000 & RD-M3000 (but not M2000) do use this.

From what I can see, direct mount is now fairly standard:

M771 (non-Shadow)


M772 (Shadow, non-removable B2 link, conventionally attached)



M610 (Shadow, B2 link removed to attach to direct mount hanger)

The differences with these mechs being that there is a barrel adjuster fitted and there were many more parts made from mild steel, including the inner cage plate, the cable arm, and the hanger adaptor. In the posher models these parts are often made of aluminium.

There are some differences in the jockey wheels:

XTR (from M980), Saint (from 820) and XT from M786 - sealed bearings, tension wheel is semi-hollow to try to shed mud
Older XT - also sealed bearings, but not mud-shedding
SLX, XT, Deore, Alivio, Acera, Altus - not sealed bearings (but quite easy to disassemble, clean, and lubricate). At Acera/Altus level you get steel, rather than stainless steel bolts.

XTR sheds a mighty 5 grams over XT using carbon fibre.

At this point for 10-speed:

Deore = SLX
XT = XTR

[Brucey]

just to clarify, the 10s dyna-sys mechs are not the same design per se; they are similarly laid out but they have a completely different shift ratio to the 9s mechs. I am presently experimenting with adaptations to these mechs to see if they can be converted to other shift ratios BTW.

I've seen relatively few bikes where the direct mount was used as intended; I suspect that manufacturers and consumers alike instinctively resist a frameset that only easily allows a single maker's RD to be fitted. The adaptor (to fit to a standard hanger) may be ugly and clumsy but it has the unintended benefit of being able to bend in a prang without wrecking the rest of the bike.

Pulley variations in rear mechs are manifold and probably deserve a whole thread by themselves. I recommend using XT/ultegra quality pulleys in most mechs if you want them to last well, but there are exceptions to this e.g. because the tooth shapes vary.

cheers

[Peter W]

Good grief! It's all too much for a simple Yorkshire lad. Who knew that changing gear on a bicycle could be made so complicated, with year on year derailleur technical 'upgrades' being essential? You get the impression that nothing ever really worked properly before! (Come back Sturmey Archer of joyful youth - all is forgiven.)

Seriously, since adequate derailleur designs have been swapping gears about since goodness knows when, WHY should they need constant year on year 'improvement' just to continue to do so? What on earth is the point? (Except, of course, the cynical one!)

[thelawnet]

I've seen relatively few bikes where the direct mount was used as intended; I suspect that manufacturers and consumers alike instinctively resist a frameset that only easily allows a single maker's RD to be fitted. The adaptor (to fit to a standard hanger) may be ugly and clumsy but it has the unintended benefit of being able to bend in a prang without wrecking the rest of the bike.

There's a fairly simple solution, with manufacturers offering in many cases now SRAM 12-speed and Shimano 11/10-speed on the same frameset, you just design a standard and a direct mount hanger and if you want to spend hundreds of pounds converting your Shimano to SRAM or vice versa, then another £10 for a new hanger won't present many difficulties.

These are to fit the same Giant frames:

Standard:


Direct mount:

[pwa]

At about the time of 9 speed, derailleur gears had reached a state of grace, with MTB and Road stuff working together, very wide ranges possible, and crisp reliable changes for anyone who took the trouble to keep their cables in good order. Nothing that has happened since is an "upgrade".

[thelawnet]

Seriously, since adequate derailleur designs have been swapping gears about since goodness knows when, WHY should they need constant year on year 'improvement' just to continue to do so? What on earth is the point? (Except, of course, the cynical one!)

Well mostly to sell new product.

If you remove barrel adjusters from your derailleur then people who don't have them on their shifter need new shifters as well. Of course it may not be a bad thing to remove your barrel adjuster if you have them on your shifter and you are trying to cut grams from your groupset weight, and it helps with differentiating new product from old - customers don't want to think you are selling them the same product with a new name, so it's helpful to have visual differences even if the function in terms of springs etc is the same.

And if you redesign your derailleur to stick out less, and give this design a new brandname such as 'Shadow', then you can persuade people that your derailleur is newer and better than the old one which 'lacks' Shadow, even though 'Shadow' isn't a feature per se, like 'this phone has a front camera and this one doesn't', it's just a different (and not necessarily better design).

And then you can have around eight different spec levels, some of which are functionally identical (no performance advantage whatsoever between prices) to significantly cheaper ones, and persuade some people to replace an existing, say 'Deore' product with an 'SLX' one that doesn't work any better.

And of course you have a total lack of independent media willing to actually debunk marketing statements such as 'this groupset is designed for XC, while this one is trekking' are a load of rubbish, and explain the technical differences between one product and another such as 'these derailleurs use a stiffer spring than this one', but instead with a straight face tell you that the new bike is 100x better than the one from three years ago even though it has only the most minimal of changes.

Of course there are some improvements over time, but the product cycle is driven by marketing not technology.

[Brucey]

I've seen relatively few bikes where the direct mount was used as intended; I suspect that manufacturers and consumers alike instinctively resist a frameset that only easily allows a single maker's RD to be fitted. The adaptor (to fit to a standard hanger) may be ugly and clumsy but it has the unintended benefit of being able to bend in a prang without wrecking the rest of the bike.

There's a fairly simple solution....

Maybe you missed the point (again) which is that the unintended benefit of this whole business is that if you use this style of derailleur on a standard hanger you have one more part that can bend (without breaking, and that might be straightened again) when you have a prang.

I for one am sick to death of frames which (quite needlessly) use yet another style of easily broken, difficult to replace crappy hanger. A 'solution' which means even more different hangers is no 'solution' at all; it is just adding to the problem....

To my great surprise it seems that RD-M4000 mechs can usually be straightened in the event of a prang; this feature is pretty rare these days. It is a 9s mech so it will work with the widest variety of shifters etc. What it isn't designed for is a close-ratio cassette though.

I only started this thread because I was surprised that some new-ish part actually had some kind of useful advantage over other stuff; it is so frequently the other way around.....

cheers

[Neilo]

That's very interesting.

I fitted a cheap 9 speed Alivio 12/36 cassette to my older 9 speed Spesh Roubaix, in combination with a 9 speed Deore M.T.B. rear mech, and the bikes 9 speed Sora shifters. It all works. The intriguing thing is though that the cheap Alivio sprockets are 'bendy' when levered with the blade of a screwdriver.(Metal bending - no free play in cassette.) This slightly affects the changing at times.

It changes properly over the full cassette range when changing down, i.e. from smaller sprockets to larger, because of the ramps, but is sometimes hesitant in changing back up, i.e. from the larger sprockets in particular to the next smaller one, but only over the three bigger lower gear sprockets. There is no hesitation changing across the higher geared end of the cassette where that sprockets are smaller and less bendy.

I did exactly the same and had the same problem, a lot of fiddling, I would adjust it so much that the problem would move the other way round, I had to give it an extra nudge to go up to the larger sprocket. I found it better to live with that than an extra shift down the cassette. I've managed to get it spot on now, it was nothing to do with bendy sprockets as you suggest, it was using the B tension screw to get the derailleur in the right place, If I remember right, the top jockey wheel was too close to the cassette, and the chain was catching on the teeth of the next sprocket, not allowing it to shift over.
It took my quite a while to figure out that one.

[thelawnet]

I've seen relatively few bikes where the direct mount was used as intended; I suspect that manufacturers and consumers alike instinctively resist a frameset that only easily allows a single maker's RD to be fitted. The adaptor (to fit to a standard hanger) may be ugly and clumsy but it has the unintended benefit of being able to bend in a prang without wrecking the rest of the bike.

There's a fairly simple solution....

Maybe you missed the point (again) which is that the unintended benefit of this whole business is that if you use this style of derailleur on a standard hanger you have one more part that can bend (without breaking, and that might be straightened again) when you have a prang.

I for one am sick to death of frames which (quite needlessly) use yet another style of easily broken, difficult to replace crappy hanger. A 'solution' which means even more different hangers is no 'solution' at all; it is just adding to the problem....

If it makes it work, it's a solution. It might or might not be a better solution, but that wasn't what I was addressing.

In terms of the 'different' hanger, the direct mount hanger is significantly stiffer. This may result in the derailleur itself being damaged (and in the case of a £20, new, RD-M4000 brought into a shop, most likely chucked in the bin and replaced with a new one, rather than spend labour rates repairing it, due to the relatively low cost, especially as a B2 link on its own sells for £10 and the derailleur could end up being bent as well) but there is a lower incidence of broken hangers, so it is not quite so crappy in that sense.