The Honda-powered team tried out the French tyres for the first time in Barcelona after the post-season test ban ended.
BAR are running an interim car as well as the old BAR005 model before launching their 2004 race car in February.
"This week's programme is essentially the start of our 2004 season," said technical director Geoff Willis.
"We have made significant advances for next year with both engine and transmission, and we are eager to start evaluating those with the benefit of our 2004 Concept car."
The BAR Formula One team has switched its tyre supplier for next season from Bridgestone to Michelin.
