The top speed figures from Friday's MotoGP free practice session at Laguna Seca showed Valentino Rossi's Yamaha leading the way on 262.9km/h, but the biggest surprise was the variation between the Ducati riders.

Casey Stoner was just 0.4km/h behind Rossi to set the second fastest top speed, but team-mate Nicky Hayden - who complained about a strange lack of acceleration - was only 14th on top speed, 10.2km/h slower than Stoner.

But that still made the American the second fastest Desmosedici, since satellite riders Sete Gibernau and Niccolo Canepa were 13.4 km/h and 17.7km/h slower than Stoner.

That meant Ducati riders were ranked 2nd, 14th, 15th and 16th for top speed. Only Scot Honda's Gabor Talmacsi was slower, with 234.3km/h.

Laguna Seca's relatively short main straight puts a greater emphasis on acceleration than outright power.