Sometimes a product comes along so obviously simple, that you wonder why no-one else thought of it sooner. Such was the case when Shimano released the DX M636 platform SPD pedals almost a decade ago. The big red pedals combined both the benefits of SPD and flat pedals, in a package that become a hit with DH racers (although the DX moniker was, and still is, used for BMX race parts). We’ve still got a couple of the pedals gathering dust in a corner of the BM office, so indestructible were they (Pfft - I'm still using a pair... -Mike).
A few years back an updated version, the grey 646 was launched, but it failed to improve upon the original and never really caught on. Step forward to 2007, and there's another successor in the shape of the M647. Their stoutness makes them ideally suited for DH and FR applications, but don’t let that put you of using them for longer XC jaunts, as we’ve been happily doing for ages, if you don't mind the slight weight penalty.
Whereas the original design employed a metal cage, the new pedals use resin in the style of the M424 pedal (although it's more like the alloy-caged 545 in size and shape). We initially feared that the indestructibility, a key feature of the originals, might be lost, be the opposite is actually true. While we've caused the premature expiry of several M545s, the M647's keep on going – the resin has a knack of shrugging off rock impacts, tending to just gouge a bit rather than break.
Inside the resin cage sits what is fundamentally an M540 pedal, which shares the mud-shedding design of the top-end M959. This sets the 647s apart from Shimano's other platform SPDs which are still using the previous, and somewhat less effective, generation of binding mechanism. The 647 offers secure and solid cleat engagement and a clear clicking out when you request it. The bearings are smooth from the box and haven’t needed any maintenance, and likely won’t for sometime yet from our experience with Shimano SPD pedals. The resin cage is quite bulky, but used with skate style shoes – such as Shimano’s MP66 shoes – presented no issues with clipping in.
Positives: Indestructible, durable, stability
Negatives: Slightly weighty
Verdict: Since introducing the world to the idea of platform pedals with a SPD core, we’ve become hardened fans and users. With the re-introduction of the classic DX pedal, an extremely tough, durable and indestructible pedal (and lighter than Shimano’s metal cage versions), combined with Shimano’s oh-so reliable SPD mechanism, they come up trumps.