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Fresh Produce: Shimano Saint SM-CD50 Chain Device

12:14 19th March 2013 by Ed Haythornthwaite


It must be about a year ago now since we first got to see pictures of Shimano’s first foray into the world of chain devices, but for some reason it has taken until now for it to finally become available. They didn’t even have any for us to use at the official Saint launch last summer. So why has it taken so many years for Shimano to make a chain device, and why one they announced one did it then take so long to become a reality? Well I’m not too sure of the answer to the first question, maybe it was because they didn’t feel the market was big enough, but I am pretty sure that the answer to the second question simply comes down to the fact that we saw it before we were meant to. Basically someone somewhere accidentally left a photo of it in a press images folder and once it was out there there was no going back.


Anyway, it has now finally arrived and it appears to be just the same as the original pictures that we saw. Shimano have decided to go down a different route to everybody else and the result is their ‘Modular Chain Device’. The main idea behind it is that you can chose how much bash protection you want to run. Shimano realised that most riders always have the same leg forwards when entering a technical section (the kind of place where you might experience an impact) and so those riders really only need to run a bash ring at a certain point, the rest never comes into play. So the bash ring that comes as part of this chain device only covers about a quarter of your chainring and you simply mount it where you are going to need it. If you’re one of those ambidextrous type riders who can lead with either foot then there’s the option to buy an extra section of bash ring which will then give you all the protection you need, and on the flip side if you don’t feel the need for any bash ring protection then you can also buy this chain device without any.

The guide itself seems to be very well made and there are some great little details like the rubber piece that’s fitted to the lower part of the top guide in order to help reduce noise. All the hardware is also captive, and to adjust and open the top guide requires just a single allen key. Shimano have gone for a slider design at the bottom and this features a replaceable wear plate which produces very little friction or noise. We’ve yet to try one out in the dirt, but the one that was fitted to a show bike did feel incredibly smooth. The lower guide is also sprung loaded and can move out of the way a little should anything hit it. Personally I’m not sure whether it needs it as the lower guide is pretty well tucked out of harms way and it definitely adds extra weight. Still you never know, one day this feature might save a load of damage.

Because of the segmented bash ring it does mean that both the upper and lower guide look a little ‘open’ when the bit of bash ring isn’t covering them. Only time will tell whether or not this is an issue, but first impressions are that it looks kind of wrong somehow. I’m sure though that as long as you have the top guide fully clamped down on the chain so it can’t lift off the ring then it should work a treat despite looking a little odd.

We’ll get this fitted to a bike and let you know how it fairs, but initial impressions are that it’s a very well made piece of kit that’s pretty competitively priced. That is unless you need more than one of the bash ring segments, or you want to be able to easily swap chainring sizes (because you really need different bash segments for each chainring size). Despite the sprung lower guide it’s still very light too.

What do you lot reckon to the idea?

Price: £99.99 inc 1 x Bash Segment, £69.99 with no Bash, £39.99 for extra Bash Segment
Weight: 149g
Chainring Sizes: 34, 36, or 38t
Mounting: ISCG or ISCG 05


  1. Hancock

    Good to see it can be used with a proper bash guard.
    Seventy quid’s, not as bad as I was expecting either. It still leaves the Superstar as number 1 guide for use with a bash guard though.

  2. Messy

    Taco bashguard is definitely the way to go for chain devices. Same amount of material as this but it’s ALWAYS in the right place. Plus, It doesn’t look weird.

  3. TigerLilly

    Terrible idea to mount the bash guard to the crank instead of the frame, a hard hit will bend the crank tabs, which leads to wobbly chainrings, which leads to chain issues.

    1. Dan

      I don’t really care too much but by your logic that would mean a “taco” style guide would write of the frame (which used to happen)

      From my personal experience if you hit something hard enough with a bashguard on your cranks to bend the tabs, the last thing I would be worrying about would be chainring wobble (which can be sorted out with a vice).
      Also bashguards have been used for long enough, by enough people to know that that isn’t really an issue.

      1. dtm

        When using a modern taco the frame wont bend or be damaged as the mounting bracket is designed to fail before the frame has to absorb that much impact. With this design the impact can’t go anywhere but into the drive train. Not ideal.

  4. Tim

    Looks pretty ugly. Won’t see anyone running two pieces of a bash guard either. Especially since they are charging £39 for a little piece of plastic. I’ll stick with e13.

    1. Ed

      They’re metal actually, but I’ll agree with you that’s it’s a fiar old bit of money for not that much. Shouldn’t they cost about a quarter of the price of a chainring?

      1. gabe

        i can understand them being more than a quarter of a chainring, as shimano will probably sell about 4 of these to every 10’000 chainrings they sell…But yeh £39 is a tad steep. Surprised they don’t do a full bash as an option at least. and I agree i dont6 really see any advantage to this method over a taco. This seem a bit like all the disadvantages of both designs with no plusses. I am a huuuuuge shimano fan with massive faith in their r&d and manufacturing processes. but this device shakes that faith a bit. seems a bit unfinished…

  5. martin dorn

    Been running one for a couple months and hasn’t skipped a beat. Using it with a zee mech and its amazingly quiet and smooth

    1. Paul

      where do i buy?!


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