The riders of Team TOUR powered by Bulls are amazed at the handover of equipment at the ZEG premises in Cologne: the racing bike they will be using for the 2013 season is not at all what they are used to seeing - and certainly not what they are used to technically. Despite all the admiration, there is also a certain scepticism at the presentation as to whether the unfamiliar technology will work so smoothly and permanently. The Bulls Alpine Hawk has several technical features. "I wanted to build a racing bike for the future," says Gerrit Gaastra, who has been working as a consultant in the Bulls development department for several years. Gaastra had to do a lot of convincing, but was ultimately able to contribute all his experience to the new model and follow his urge to innovate. The charismatic Dutchman has been working in the industry for more than 25 years, and the Gaastra name has been an integral part of the cycling world for four generations. In the Alpine Hawk, he wants to unite important new developments: the eleven-speed, electronic shifting, disc brakes and tubeless tyres. But it was not so easy to bolt all these things onto a frame - the planned configuration had to be incorporated into the development right from the start.
But even on closer inspection, the Bulls doesn't look like a cobbled-together experiment. All components are visually and technically well integrated, all cables run inside the frame and the Di2 battery is hidden in the seat post. Despite the design for disc brakes, the carbon frameset remains relatively light - 1,070 grams for the frame and 417 for the fork are a good average weight for the 2013 model year. A curve in the down tube, the top tube, which is very flattened at the rear, and the curved seat tube make the frame very unique - it looks a little as if they have borrowed even more from mountain bikes in addition to the disc brakes. At first glance, the seat angle seems extremely slack, with the seat post leaning over the rear wheel at 71 degrees. However, the effective angle measured from the bottom bracket to the saddle is 73.5 degrees due to the kink in the tube, which is typical for road bikes. This trick is intended to realise two effects: Firstly, the seatpost can flex better due to the flat angle, which benefits comfort at the rear. The front derailleur also sits slightly offset behind the seat tube, which gives the developers the freedom to make the lower connection to the press-fit bottom bracket shell wider on both sides and therefore stiffer than on conventionally built frames.
Next eye-catcher: Disc brake
Shimano offers the mechanically actuated CX75 as a cross brake, making it the perfect match for the Dura-Ace levers and delivering very high braking power, good modulation and a defined pressure point. And it is surprisingly light: the 140 millimetre disc in sandwich construction made of steel and aluminium weighs 89 grams, plus 170 grams per brake calliper. The weight disadvantage is a good 200 grams compared to a Dura-Ace rim brake system, invested in a very secure feeling. Combining the brake on the rear wheel with the Dura-Ace eleven-speed transmission was not easy. In the end, the decision was made to increase the rear mounting width of the Alpine Hawk to 135 millimetres instead of the usual 130. This meant that hubs from the mountain bike segment could be used.
As a result, the sprockets now sit a little further out, which is why the chain line of the Dura-Ace drivetrain is quite tight - with a slightly imprecise adjustment, the shifting is less tolerant. But with precise adjustment, everything works perfectly - and thanks to the electronics, permanently. The XTR hubs were built quite stably, with 32 crossed spokes and a ZTR Alpha 340 aluminium rim from NoTubes, on which Schwalbe's Ultremo ZX Tubeless sits, which proved to be surprisingly fast in TOUR measurements (see TOUR 9/2012->). Regular TOUR readers should be wary of the rim: Last summer, the extremely light aluminium Rundling made rather dubious headlines at the TOUR Transalp with its folding tyres popping off. According to our assessment, the jumps under braking heat were the result of an undersized rim flange and a very flat brake track, which did not provide sufficient grip for a normal tyre. However, the tubeless tyre is held in place by a special bead in a groove in the rim base, which means that the sidewall and rim flange have little influence on the tyre's grip. Braking heat can also be ruled out here.
Schwalbe product manager Christian Lademann also views this combination with a clear conscience: "We have carried out tests up to twelve bar pressure without the tyre jumping off. That's about twice the recommended pressure for a tubeless tyre. However, I still consider the combination with folding tyres to be critical."
In practice, despite all the innovations, the Bulls rides like a normal road bike. The riding position is not too stretched and suits marathon riders, the handling is neutral. The suspension delivers what the good lab results promise, but the saddle could be made a little more comfortable with a seat post with offset. The fork is comparatively stiff. The function of the new Dura-Ace Di2 is beyond reproach and the powerful brakes are a revelation. The Bulls Alpine Hawk with Ultegra Di2 and XT-level disc brakes is available now for € 3,299, the top version shown here will be available in late summer for € 5,555.
Price complete wheel 5,555 Euro
Weight 7.2 kilos
Reference/Info www.bulls.de
Frame sizes** 50-60, 2 cm each (56)
Seat/steering angle 73,5/73,5°
Seat/top tube/head tube 514/560/181 mm plus 15 mm headset cap
Wheelbase/caster 990/52 mm
Stack/Reach/STR*** 579/390 mm/1.49
EQUIPMENT
Fork Bulls Carbon Lite Fork
Steering bearing FSA, top 1-1/8, bottom 1-1/2 inch
Brakes Shimano CX75 (v/h 140 mm)
Gearshift/bottom bracket Shimano Dura Ace Di2 (50/34 t, press-fit)
Wheels/tyres Shimano XTR/NoTubes ZTR Alpha 340/Schwalbe Ultremo ZX Tubeless
Handlebar/stem FSA Energy/FSA K-Force New Ergo
Saddle/post Fizik Arione/FSA SL-K (27.2 mm)
* The frame set accounts for 40 per cent of the overall score and the equipment for 60 per cent. Individual grades are included in these ratings, only some of which are printed for reasons of space. The grades are calculated up to the final grade with all decimal places; however, for the sake of clarity, all grades are given with rounded decimal places.
** Tested frame size greased.
*** Stack/reach: projected vertical/horizontal measurement from the centre of the bottom bracket to the top of the headset; STR (stack to reach): Values between 1 .45 and 1 .55 indicate a sporty riding position, values below are race-like, above are comfortable.
**** Adjusted weight for frame size 57 cm and fork steerer length 225 mm.
