While Jorge Lorenzo was in a positive mood following the MotoGP two-day test at Brno this week, Colin Edwards continues to be frustrated by the lacklustre performance of his Michelin tyres.

Edwards was one of the more vocal critics of Michelin following a dismal showing in the Czech Republic Grand Prix, one that saw the French tyre manufacturer record a finish no better than ninth place.

Indeed, the Tech 3 Yamaha rider was affected more than most as he finished down in a disappointing 14th, just behind team-mate James Toseland, but well over a minute behind race winner Valentino Rossi.

Deciding to remain at Brno to take part in the ensuing collective test, Edwards was pleased to have made progress but questions why similar performance couldn't have been achieved on the race weekend.

"I don't know if we actually improved anything," he told MotoGP.com. "I think we could just have found something that should have used on Sunday. We need to sit down and think about the situation a little bit."

Meanwhile, Edwards is encouraged by MotoGP's endeavour to cut corner speeds following a spate of high-speed crashes in recent rounds. Pointing out that the series has 'outgrown' the circuits on the calendar, Edwards is hopeful something can be done without ruining the spectacle at the same time.

"There are a couple of issues. We've got bikes reaching the safety road now, and that's because of the corner speed. Tyre development has outgrown the tracks that we use.

"We need to engineer something for better safety, and also for a better show. I'm all for making it a bigger spectacle, but two guys out in front with a twelve second lead after six laps? It's a joke to me."