Hi Felixthecat and Faith
As Faith said forte means resistant and strong but not only. This sentence is more than a double sense, it can be read in many ways... and being on VRossi helmet I'd think particularly to the following:
Forte refers to speed: (Andare) più forte non si può
Impossible to run faster
And to being smart, cool: (Essere) più forte non si può
Impossible to be smarter/cooler
Thanks walnut, that helps and makes a lot more sense than what I had come up with.
Thanks to the moderator for switching this to the Italian area from the Spanish. Didn't realize I wound up in the wrong section.