Vision Metron 6D Integrated Bar and Stem

The Vision Metron 6D, as used by Vision's sponsored pro teams in the WorldTour, is a super-aero, super-stiff integrated cockpit with a comfortable, ergonomic shape that will reduce drag by a measurable amount compared with a round-profiled bar and separate stem. It's a lot of money to pay for a handlebar, but if all other aero and fitness bases are already covered it could be a worthwhile upgrade for serious riders looking to save watts on race day. However, it won't save any weight over the standard bar/stem and could be a bit stiff for less powerful riders.

Compared to deep-section wheels, integrated cockpits only arrived yesterday. This is because as wheel technology has matured, bike designers have turned to the other areas of the bike and have discovered that the leading edge – the bar and stem – is crucial in aerodynamics, and many of the top aero bikes already come with dedicated aero bar/stems by their house brands.

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To put some numbers on it, Specialized claims its latest Aerofly II bar saves 20-plus seconds over 40km compared to a round bar. Meanwhile, by Zipp's calculations, its SL-70 handlebar creates just 0.11 Newtons of drag compared to a round-tube section handlebar's 0.74 Newtons, equivalent to a saving of 6.4 watts.

Vision does not supply any wind tunnel data for the Metron 6D – surely missing a trick here – and does not make any claims for the Metron 6D compared to its competitors, but it's likely that the lack of stem bolts and faceplate, combined with the smooth, uninterrupted sweep from the top and sides of the wing-shaped bar into the stem section, makes it pretty fast.

The 6D has a different shape from the 5D, which is still a current model. It is completely straight across the tops, like a standard bar, whereas the 5D is swept forwards.

Incidentally, there's a Metron 5D ACR (Aerodynamic Cable Routing) which completely conceals cables and hoses, taking them inside the stem and into the head tube – you would need to check your frame's compatibility – but no Metron 6D that does that (yet).

As for the Metron 6D's weight, well, Vision says it has a 'great strength-to-weight ratio', not claiming anywhere that it's light, and that will be because it's not: it was heavier by 15g than the fairly low-end aluminium ITM Visia bar and stem, including all bolts, that it replaced. I suspect that this is because pro bikes – even those with disc brakes – can now hit the UCI minimum weight limit easily, meaning a bit of heft can be built into the bars.

Unboxing and set-up

The Vision Metron 6D comes in a big box containing everything you need to set it up for all available types of braking and shifting. Underneath the stem is a compartment for a Di2 three-port junction box and there's a cover with included bolts and washer. It's also drilled for a Di2 bar-end junction box.

The internal cable routing holes look big enough for hydraulic hoses plus standard gear cables, and so will of course accommodate mechanical gear and rim brake cables. I'll admit I cheated and didn't cable them to capacity because my test rig is equipped with 'vintage' STIs with external cabling, which would cause a wind tunnel meltdown.

Regardless, Vision has ticked all boxes: the cable holes are directly opposite each other so there's no need to poke, force and curse cables and wires around tight corners and there's even a complimentary pair of plastic tweezers in the box to assist with this. They are actually just holes rather than channels inside the bar, so you do have to catch the cable end and hook it out.

There's a bag of optional proprietary aero spacers, including a dedicated top one that sits flush underneath the stem and one for the bottom of the stack that sits on the headset bearing, plus a top cap and even a bung.

None of the spacers is designed to sit above the stem, so you have to cut your fork steerer down if you want to use the Metron 6D-specific top cap directly on top of the stem. If you don't want to cut your steerer – as I didn't because I was only testing the bar – you can run standard round 1 1/8in spacers above it and then a regular round top cap, but that rather defeats the object of an aero bar.

On the subject of bar height, the Metron 6D only comes in a +/- 6-degree rise – although there are different stem lengths and bar widths to choose from – so before you buy you should do some careful trigonometry to make sure it's not going to wreck your bike-fitted position.

Vision also supplies an out-front Garmin mount plus a generic-computer out-front mount. I used the Garmin mount and found it was more solid than some tri-bars I've used in the past. There was no vibration at all and the Garmin clicked in very firmly. If you fancied 'doing a Hirschi' and using your computer/computer mount as tri-bars, this would be more than up to the job. 

Performance

All of the Metron 6D's 40cm, 42cm and 44cm width options come with an 80mm reach and 125mm drop, which broadly classifies them as compact, making them easy to ride with minimal change to overall position for the changes in hand position.

Once I got my contact points there or thereabouts using round spacers, as mentioned, I found the Metron 6D comfortable to hold. The tops supply a bit of extra surface area while climbing, the flat section as it turns through 90 degrees to meet the shifters also gives the heels of the palm a bit more support, while the classic bend of the drops felt nice and familiar, just like any other bar.

However, while it was great ergonomically, I found the sheer stiffness a little excessive for even a two-and-a-half-hour group ride in the lanes, even though it was a fairly pacy one. I am prepared to admit that I'm not the most powerful or heaviest rider, and since this bar was developed with Vincenzo Nibali and the Merida team then it's hardly surprising that it's overkill for many less powerful riders.

Its extreme rigidity showed up the flex in my bike's front end, which wasn't noticeable with a common-or-garden bar and stem.

Vibration damping on smoother tarmac was great, especially with a quality bar tape like the Arundel Art Gecko (which, incidentally, is reusable after all).

I concluded that in order to get the ride quality out of the Vision Metron 6D that it is designed to give, you need to be a powerful rider and you need to fit it to a bike that's itself already very stiff. Vision can't be criticised for this: the Metron 6D was developed for pro riders, after all.

Value and conclusion

Yes, yes, you could buy a whole bike for less, but the Vision Metron 6D is by no means the most expensive integrated cockpit out there. In 2018 we reviewed the Deda Alanera, which cost £699 at the time and the updated version with more integrated cabling costs the same.

Even more expensive is the MOST Talon Ultra, at £750, which is only compatible with the Pinarello Dogma F12.

The Trek-specific Bontrager Aeolus RSL VR-C integrated bar/stem is a little cheaper at £549, while the PRO Stealth Evo costs £449 and is compatible with any bike. And there are, of course, Chinese carbon bars that are cheaper still.

So the Vision Metron 6D is not outrageously expensive in the integrated cockpit market by any means.

> How to get more aero without spending a fortune

We don't have the capacity to aero test at road.cc, so I don't have any of my own data to prove that the Metron 6D was faster than the round-profile bar, or indeed any of the above bars. However, there's enough out there already to prove that aero bars are faster than round ones – that's not in doubt.

In summary, the Vision Metron 6D would be the missing piece of the aero jigsaw for a rider who has already invested in aerodynamics, is at the top of their fitness game and is prepared to spend the money to get that little bit more out of their performance, but if you're not a serious racer there are upgrades that are easier on the body, and the Metron 6D won't save any weight over a standard setup.

Verdict

Uncompromisingly stiff aero cockpit that's perfect for strong racers looking to save watts but not shave grams