Aug.5 (GMM) When F1 farewells grooved dry weather tyres at the end of this season, Bridgestone must come up with an alternate way of visibly distinguishing between the 'hard' and 'soft' compounds at races.

It is believed the front-running idea for the return of slick tyres in 2009 is to colour white the sidewalls, rather than an inside groove as is the current practice.

The concept, and possibly others - including the possibility of colours other than white being used - will be tested prior to the beginning of the 2009 season, Bridgestone sources report.

Meanwhile, it has emerged that F1's official tyre supplier plans to use a reflective white paint for the groove for the first-ever night race in Singapore on September 28, according to the Dutch magazine Formule 1 Race Report.