Ducati's MotoGP Speed | Ask The Geek

Why is Ducati's MotoGP bike so fast compared to the other bikes?

Chart of Ducati speeds compared to Honda, Suzuki, and Yamaha at MotoGP rounds
This chart shows the top speed recorded by the fastest Ducati, Honda, Suzuki, and Yamaha in the Qualifying 2 session at each MotoGP round in 2015.Sport Rider

Please explain why the Ducati MotoGP bike is so fast compared to every other bike in the field.
Gary Ritts
Los Angeles, CA

Ducati's Desmosedici MotoGP bikes have always been the class of the field in terms of horsepower and top speed, from the first version in 2003 to the current model. To put some numbers on just how fast, and how fast compared to the other bikes, I looked at top speeds from all of 2015's Q2 qualifying sessions for the top 12 riders.

The fastest speed in all the sessions was 217 mph, set by Andrea Iannone at Mugello, Italy. A Ducati posted the fastest speed at all but two of the 18 rounds, with Andrea Dovizioso fastest at seven tracks, Iannone at eight, and Yonny Hernandez at one. At eight of the events, Ducatis were one and two in the top-speed charts; at one, they were the top three, and in two rounds—Misano and Mugello—Ducatis filled the top four places in the top-speed results. On average, the fastest Ducati in qualifying posted a trap speed 2.5 mph higher than the fastest Honda, 3.7 mph higher than the fastest Yamaha, and 8.1 mph higher than the fastest Suzuki. That is an impressive list of results, but it seems to be getting even better this year: At Qatar, the opening round of the 2016 series, the top seven bikes in one practice session were all Ducatis, with the eighth-placed bike more than 6 mph off the fastest Ducati.

Top speed is more about power and aerodynamics than anything else, and while top-end power is important, the bike must also accelerate well off the turns and onto the straights. The Ducati and Honda V-4 layout might help here compared to the inline-four engines of the Yamaha and Suzuki. While the V-4 does have more spinning parts and bearings in the top end of the engine, there are fewer main bearings on the crankshaft (three versus five), and the 90-degree V angle of both bikes eliminates the need for a balancer shaft whereas the uneven firing order of the inline-fours necessitates a balancer shaft. Overall, the V-4 engine might have less friction than the inline-four. (That said, reports are that both the Honda and Ducati crankshafts spin backward relative to the wheels, and this would require an extra shaft inside the engine; the Yamaha also spins backward, but the jackshaft to accomplish this could double as the balance shaft.)

The Ducati's desmodromic valve system also helps the Desmosedici's power. While all the other manufacturers use pneumatic valve operation with compressed air or nitrogen closing the valves, Ducati's system closes the valves with a mechanical actuator. One of the inherent advantages of desmo valve operation is a higher rpm ceiling, but that is not much of an issue here; the maximum bore size regulated in MotoGP effectively sets the rpm limit for the bikes. More importantly, the mechanical closing of the valves reduces friction and allows more aggressive cam profiles and timing to be used, with a corresponding increase in power.

Turning to aerodynamics, again the V-4 engine has an advantage over the inline-four, with a smaller frontal area. The rider is also an important part. While neither of Ducati’s factory pilots are the shortest or lightest on the grid, both are fairly compact: Dovizioso is 5-foot-5 and 147 pounds, while Iannone is 5-foot-8 and 147 pounds. The Ducatis and the riders might not have much of an advantage over the Hondas of Marc Marquez (5-foot-5 and 130 pounds) and Dani Pedrosa (5-foot-3 and 112 pounds) but certainly would over Valentino Rossi (5-foot-9 and 152 pounds) on the inline-four Yamaha M1.

Looking only at the numbers, if the Ducati’s advantage was strictly aerodynamic it would have more of an advantage at the faster circuits. But that is not the case: Ducatis had the top four speeds not only at Mugello, the fastest track on the calendar, but also Misano, one of the slowest. Put everything together and it points to the Ducati being the most powerful bike while also enjoying an aerodynamic advantage over the Yamahas and Suzukis. The Desmosedici’s desmo valve operation is surely part of the equation, but it’s also worth noting that Ducati in MotoGP has historically compromised some rideability in the pursuit of all-out power.