Pedro de la Rosa has explained that McLaren's slow pace at Jerez - which saw him beaten by a Force India - was down to the team running some 2010 specs.
McLaren spent the first day of this week's Spanish test evaluating compounds and casings for Bridgestone's 2010-spec rubber.
One of the requirements was to run with the upcoming restriction on tyre warmers while the second was to use a heavy fuel-load due to the ban on refuelling.
And de la Rosa's lap times were proof that it is not going to be easy for the drivers as he finished seventh out of the eight runners, 2.7s behind pace-setter Seb Vettel.
In fact the Spaniard was so far off the pace that even the Force India of Giancarl Fisichella was ahead of him on the timesheets.
"Running without tyre blankets makes it harder to get heat into the tyre - but that's the objective for next year and that's why Bridgestone will supply the teams with different compounds," the McLaren tester said.
"We managed a lot of laps today and the work with the tyres was very positive."
Source : Planet F1