First ride: Shimano Ultegra 6870 disc
Shimano Ultegra 6870 disc groupset
As the autumn weather starts to grip northern Europe, Shimano had the foresight to arrange its demo days for the European press in Sicily on the slopes of Mount Etna.
A tough little climb, Etna Sud has many switchbacks and a gradient that rarely drops below 10 per cent - surely an ideal place to test how well the 11-speed electronic groupset shifts under load and, when you've turned around at the top, just how well the disc brakes work, too.
Hitting speeds of over 80kph on the descent, the discs were sure to get a good workout and so it proved. Deliberately dragging the brakes to simulate an alpine descent stuck behind a coach or the like you could hear the metal rotor get hot as the whole system soaked up the heat generated.
But despite prolonged dragging the stopping power never altered and the feel at the lever remained constant and predictable, which was impressive. The noise soon dissipated once normal descending resumed or the ground levelled out.
When it came to the shifting it was every bit as good as you'd find with 9070 series Dura-Ace, performing seamless shifts under full load time after time with no fuss. Of course the weight and materials aren't quite as good as 9000 but during the brief first ride I simply couldn't fault it and frankly couldn't have told the two apart.
If there was one downfall to the BMC test bike that Shimano had built up, it was with the RX31 wheels. While up to the job in terms of being able to cope with the high level of braking power, they were heavy. At a guesstimated weight of around 2kg they certainly should have been up to the job but the lack of rigidity to the wheels once mounted in the frame was enough to get the disc rubbing on the pads when riding even lightly out of the saddle.
It's obviously very early days for road disc brakes and there will no doubt be countless improvements made in the coming years. But based on our ride, as a starting point the Ultegra version is already very worthy of consideration.
Ultegra 6870 prices
Rear derailleur Ultegra Di2 6870 £219.99 250g
Front derailleur Ultegra Di2 6870 £199.99 155g
STI gear shifters Ultegra Di2 6870 from £299.99 295g
E-tube SEIS handlebar cable set from £89.99
E-tube SEIS frame cable set £209.99
E-tube SEIS wire lengths from 300mm £19.99
E-tube SEIS battery mount £99.99
E-tube SEIS battery - internal £129.99
E-tube SEIS battery - external £59.99
Battery charger from £64.99
STI gear shifters ST-R785 Di2 inc caliper £599.99 515 + 263g
Disc brake rotor - single £54.99 205g