Updated

A new environmentally friendly tire and cool morning temperatures had NASCAR drivers clocking speeds they weren't even sure were possible Tuesday.

On the first day of a closed tire test on Indianapolis' historic 2.5-mile oval, Mark Martin wrote on Twitter that he had hit 212 mph in the morning. When Jeff Gordon saw the post, he asked his own team how fast he reached and said he was told 214.

Drivers attributed the speed to almost perfect conditions in the morning -- good grip and a cool track. In the heat of the afternoon, Gordon said the tire wear increased and the speeds slowed.

Clearly, though, those on the track were encouraged by the results.

Gordon and Trevor Bayne both said they would embrace a night race at Indy, too.