Four months after the race premiere at Unbound, the world's most famous gravel race, Factor has presented the Ostro Gravel to the public. The new product is set to compete for podium places in all the world's gravel races in the future, and Factor is confident of its chances of success thanks to consistent aero optimisation. According to Managing Director Rob Gitelis, the Ostro Gravel is even "the fastest gravel bike in the world". TOUR has already been able to test the bike. Even without a visit to the wind tunnel, we came to a surprising conclusion.
The Ostro Gravel is not only similar to the Ostro VAM in name, it is also supposed to achieve comparable aero values to the fast Bolide, at this year's Tour de France decorated with two stage wins. Factor favours tubular shapes in the wing design. The centrepiece is the one-piece cockpit, which is designed to reduce air turbulence and make the Ostro Gravel faster.
Wind tunnel measurements are still reserved for competition bikes at TOUR, but according to our riding impressions, the Factor has to compete for the unofficial title of the fastest bike in the world. Gravel bikes stretch. At just over eight kilograms, it is on a par with comparable competitors. However, the Ostro Gravel, whose frame and fork are not maximally torsionally stiff, reacts somewhat sluggishly when setting off. Once on the move, the stable bike with its relatively upright riding position is hardly upset - as long as you don't take an angled course under the wide tyres, as tight bends require precise steering.
The unconventional steering behaviour is due to the so-called crossover concept of the gravel racer, which with narrower tyres (30 to 35 millimetres) should also function as a road bike and steer around corners with a little more agility thanks to the smaller wheel diameter. However, the Factor then offers even less comfort than with the 40-millimetre tyres fitted.
Overall, the Ostro Gravel, like the similarly designed Wilier Rave (TOUR 1/2022), represents a compromise - and it comes at a high price. The six models, all equipped with wireless shifting from SRAM, cost between 8120 and 10800 euros.
The Factor Ostro Gravel in detail
- Price9710 Euro
Frame/fork/steering bearing weight* 1044/532/88 grammes
Frame sizes** 49, 52, 54, 56, 58, 61
Seat/top tube/head tube 500/565/150 millimetres
Stack/Reach/STR*** 589/391 millimetres/1.51
Wheelbase/caster 1030/62 millimetres
Equipment
Drive/Circuit SRAM Red eTap XPLR (1x12; 44, 10-44 t.) Brakes SRAM Red (160/160 mm)
Wheels/tyres (weights)**** Black Inc Thirty-Four/Goodyear Connector Ultimate 40 mm (f./h. 1434/2006 g)
Measured values & individual scores*****
Weight of complete wheel 8.1 kilos Grade 2,0
Steering head stiffness 70 Nm/° Grade 4,0
Lateral stiffness Fork 38 N/mm Grade 3,7
Bottom bracket stiffness 47 N/mm Grade 3,3
Seatpost spring stiffness 66 N/mm Grade 3,3
Spring rate fork 43 N/mm Grade 2,3
*Weighed weights. **Manufacturer's test size in bold. ***Stack/reach projected vertical/horizontal dimension from centre of bottom bracket to top of head tube; STR (Stack to Reach) 1.36 means a very stretched, 1.60 an upright riding position. ****Wheel weights including tyres, cassette, quick release/threaded axles and brake discs if applicable. *****Individual grades, which are weighted differently in the overall grade, are only partially 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.
Jens Klötzer
Editor
