Symonds: F1 2007 is impossible to call

The winter has seen an almost unprecedented level of driver movement, and the teams must also acclimatise to the Bridgestone tyre monopoly after six seasons embroiled in a tyre war.

"If you look around the teams there is so much change this year, more than I can remember for many, many years, so it really makes it the most difficult pre-season call that I can remember," Symonds told autosport.com.

"And to be honest I am not a great fan of trying to make pre-season calls because it is difficult."

Every team except Toyota will start 2007 with either an altered driver line-up, or a different engine or tyre supplier.

The key protagonists in the last two world championship battles have all changed places, with Fernando Alonso moving to McLaren, Kimi Raikkonen joining Ferrari, and Michael Schumacher stepping down.

The arrival of Lewis Hamilton and Heikki Kovalainen also creates the unusual situation of two rookie drivers occupying seats in potential title-winning teams.

Despite his reluctance to make predictions, Symonds was cautiously optimistic about Renault's preparation for the new year.

"We are looking pretty optimistic, we know what our targets are in terms of reliability," he said.

"We know we are not out there testing as much as we have done in previous years so we are very realistic about where everything is, but we feel pretty good about it.

"As I always say, how competitive you are going to be is a relative thing. It doesn't just depend on what we do, it depends on what the others do."