On a bike, there are three contact points, the saddle, (aero or drop) bars and pedals, and we make much fuss about which ones we like and which we hate, and why this one is off just a hair, and that one is all wrong for us – but we rarely stop and think about the parts of the bike those contact points are connected to. Typically, our seat posts and stems and cranks are simply there; no changing needed, no thought put in. Well, after a call from Vision and a weekend or two with their newest Metron crankset, we recommend that you give serious thought to what those pedals are spinning.
We received the crank in 53/39 with 175mm arms, but what interested us was the bottom bracket specification – BB386EVO. 386 is a wider standard than our BB30 cranks, but uses a pair of spacer adapters to allow for cross compatibility. According to Vision, the wider crank spindle not only increases stiffness and reduces weight through the bottom bracket, but allows the usage of straighter crank arms, which should reduce squirm from the arm under load, as well. From a numbers perspective, BB386EVO is a win all the way around, and our experience bears this out. The crank is not merely noticeably, but significantly stiffer than our previous aluminum Vision TriMax Compact in BB30.
Now, this is in part due to the nature of moving from an aluminum crankset to carbon, but under hard acceleration, our previous BB30 crank tended to squirm a bit; there is no motion whatsoever with the Metron crank. Similarly, the crank arms themselves feel more direct. The aluminum arms gave a slightly numb feeling to the power arc of the pedal stroke where the carbon arms appear to have a direct link with our back tire’s go button. The straighter crank arms are claimed to have less deflection by Vision and we absolutely believe it, but they also pose a particular problem for riders whose feet are turned out – “duck feet” riders, of which Devon happens to be a card-carrying member.
To give a better mental image, here is Devon’s foot position on an Ultegra 6700 BB30 crank:
And here is his foot position on the Metron:
So even he’s got clearance, albeit not much. This is all due to that straighter crank arm and wider spindle width we mentioned earlier – by necessity, it gives less heel clearance than a curved BB30 crank arm. But if Devon can ride it, you can, too.
We’ll be putting more miles on the Metron in the coming weeks, so keep an eye out for our long-term review. For now, though, everything you need to know about the Vision Metron crankset can be summed up in one word: Stiff.