KTM could bring 2019 bike forward after prototype's Jerez debut

Test rider Mika Kallio rode the prototype in the Spanish Grand Prix at Jerez earlier this month and finished ahead of KTM's full-time works riders Espargaro and Bradley Smith on their current-spec bikes.

Espargaro, who is convinced the new bike is a marked improvement, said he does not want to "waste more time" with the old version but admitted KTM cannot yet make the switch for its full-timers due to engine-related time constraints and homologation regulations.

"KTM is trying, they are going to make a big effort to giv ite to us for maybe Spielberg," Espargaro said.

"Honestly I don't want to waste more time with that bike [the old one], I think the potential is really big on the new one."

Espargaro, who finished 11th to Kallio's 10th at Jerez, said he anticipated that outcome but conceded it was "not nice" to be outrun by the test rider.

"We could imagine the result from the first day I exited [the pits] behind Mika," said Espargaro.

"When I tested the bike I was surely half a second faster than myself [on the old bike].

"When the conditions were more tricky, with low grip on the track, the new bike works much better.

"I am happy for that. It is not nice that Mika, the test rider, beat us, but is a pretty good sign that the new things coming are working good."

Kallio, who said he enjoyed being "the clear fastest KTM" in the Spanish GP, explained that the prototype bike's strongest point was its consistency over a race distance - even if it struggled for initial grip on fresh rubber.

"Maybe at the beginning I was struggling a little bit more than compared to my team-mates about the grip level on the rear, it was not so easy to follow them," he said.

"Then lap by lap I saw that, from the first lap till the last lap the pace was exactly the same so that is really good.

"I saw the other guys started to struggle more with the grip, especially coming out of the corners they were spinning a little more than me.

"That is the really good point of the new bike even if there is some negative things.

"Everything is so new at the moment so we need to work more and see if we can find some [fix] for those problems."

Kallio will make the next of his planned five 2018 wildcard appearances in June's Barcelona race, where conditions are likely to be similar to Jerez and where Espargaro believes the current-spec bikes will once again "suffer" compared to the prototype.