BH G6.0 (2013)

The BH G6.0 is a beautiful, light-as-air carbon road bike that's super fast, very responsive and a joy to ride on your own or in a bunch.

Every since Cervelo launched their S1 back at the turn of the century aerodynamics has been considered at the design stage as much as weight and stiffness. The continued advancement in carbon fibre moulding means more complex wind cheating shapes have also become possible. With a lot of conflicting wind tunnel results and manufacturers claims out there does an aero frame really make that much difference? The BH G6 8.0 has been thrashed around the A-roads and lanes of Wiltshire, Somerset and Dorset to find out.

The G5 which, as you can probably guess, preceded the G6 came with an aero seat tube but that was it really with regards to the aerodynamics; it was however very well received thanks to its high levels of stiffness especially at the bottom bracket area. The G6 has improved on that, being designed around a BB386 bottom bracket - the latest standard of BB that uses BB30 press fit bearing cups but spaced at 86.5mm instead of the usual 73mm. This not only increases stiffness due to a larger cross sectional area but also allows BH to use large profile tubes to create the aero effect.

BH use core removal technology to create the monocoque frame which uses high pressure to remove imperfections in the carbon fibre. This allows them to put material where they need to and remove it where they don't, the result – a sub 900g frame where everything is carbon fibre including the dropouts and the front mech hanger - though there is a replaceable alloy gear hanger though should you require it.

The fork is specific to the G6 and has been designed to work from an aero point of view (BH claim it's the most aero fork they've developed) with the downtube drops down behind it with very tight clearances. A large junction at the fork crown should see an increase in stiffness and directness in the steering.

On our medium test model the headtube is 150mm tall and to cut through the wind it virtually matches that for depth creating a web between top and down tube. This and the huge bottom bracket area allows the down tube to be 70mm in the vertical plane while being kept narrow in the other in a bid to cut drag. The clearance for the front tyre is tight, just as it is at the rear where the seat tube is scalloped around the rear wheel, a wind cheating trick usually reserved for time trial frames.

Keeping the rear wheel in check are some massive chainstays, rectangular with a height of 50mm which aren't going to let any form of flex through as you stamp on the pedals. In contrast the seatstays are narrow, a usual ploy to remove some of the harshness from oversize frame tubes.

The 8.0 part of the G6 8.0 is the model number. Basically you have the same frameset throughout but the kit specs change. Ours comes with Ultegra mechanical and is priced at £2999.

The other options include:

8.1 : SRAM Force - £3499

8.3 : Ultegra Di2 - £3999

8.5 : SRAM Red - £4999

8.7 : Dura Ace - £5999

8.9 : Dura Ace Di2 -£7999

As far as the finish goes I think it looks great and the photos really don't do it justice. It does come with red highlights instead of the blue if that's more your thing and to be honest it does clash less with the wheel decals. The size range is quite limited though with only five to choose from giving top tube lengths of 52cm to 58.5cm.

So, is it any faster than a more standard frame? Well to be perfectly honest, who knows? A lot of wind tunnel tests and results very rarely have any bearing on real world conditions but one thing is for sure, the G6 is fast, very fast. An all up weight of 16lb means it accelerates up to speed with little resistance and once there it just keeps rolling. Speeds of 25-30mph on the flat obviously still require effort on the rider's part but it does feel less than I have noticed with other bikes. The wheels help, Vision Trimax T42's roll nicely and are well built. They aren't truly aero at only 42mm deep but as Mat said in his review of them back in August they are 'versatile for everyday use or racing.'

It's alright being able to work well on its own, on the flat, but unless you're time trialling up and down your local drag strip all the aero benefits don't make much difference if you lose out on the hills or through the bends. Thankfully though the 16lb all up weight and the high stiffness levels means the BH is a good climber whether you're in the saddle tapping it out or honking up a 25% lung buster - everything feels stiff beneath you and you're certainly not wasting any energy through the frame.

Descending is also great fun. The front end tracks with confidence following whatever line you put it on, chopping and changing if needed. One of my favourite downhills that I've ridden hundreds of times really shows up any weakness in a test bike. Just under a mile long with most of it at 15% it's twisty and technical through trees and steep banks but it didn't throw up any concerns for the G6. Each change of direction was direct and precise with the front end tracking exactly where you pointed it. The rain and frost-damaged surface was no problem for the fork, as while it's very stiff it also soaks up road buzz surprisingly well - aided by the slight flex of BH's own brand carbon handlebars.

Also receiving a special mention are the Michelin Lithion 2 tyres. For what are essentially training tyres they roll amazingly well and give really confident grip levels and feedback.

Ultegra is a great groupset, virtually identical to Dura-Ace with regards to performance yet more realistically priced. All the cables route internally through the frame (so that it works with both Di2 and mechanical) and judging by how sweet the shifting is BH has obviously avoided any tight bends anywhere. FSA's SL-K Light BB386 carbon chainset is the only deviation away from Shimano and it's a beautiful bit of kit and very stiff. The thin profile (front to back) cranks work well with the wider BB standard keeping the Q-factor as minimal as possible. It is odd to have a compact chainset on an aero road bike but BH obviously know its market and there is an 11 sprocket at the back so you're going to be moving at a fairish old lick before running out of gears.

Downsides? There are a couple but really nothing that's a deal breaker. All that stiffness means a bit of harshness and discomfort does come through on long rides. The longest ride I did was around five hours and it was starting to tell a bit on my wrists and back towards the end. The extended seat tube removing any flex you'd receive from a standard seatpost is part of the problem while the San Marco Zoncolan saddle is the other as there isn't much give but on the flipside the slightly unorthodox shape does work well for getting down in the drops.

Those deep tube profiles and 42mm rims do make the G6 susceptible to cross winds as well - gateways in hedges can make for some interesting lean angles!!

Three grand is a lot of money for a bike but when you look at the kit level you're getting; sub 900g frame, BB386, carbon wheels and an Ultegra groupset - I think the G6 8.0 is also good value for money. It's more than just a point and shoot bike, the G6 8.0 is a great all rounder. I think we might have found a contender for the road.cc Top Ten 2013.

Verdict

Fast, light, fast, well specced and...um......did I mention how fast it is?