Stewart-Haas Racing duo Tony Stewart and Ryan Newman will both be forced to start the Daytona 500 from the back of the field after tangling in the final practice session ahead of Sunday's race.

The pair were running together in the draft when Newman suffered a right rear tyre failure on the #39 US Army Chevrolet in turn two, spinning in front of Stewart's #14 Office Depot/Old Spice car.

With nowhere to go, Stewart slammed into the side of Newman's car which then made contact with wall before returning to the pits with heavy damage to the right rear. He will now switch to his second back-up car of the week having previously switched to a back-up after his incident in the Gatorade Duels.

The car he will race in the 500 was slated to be Stewart's back-up but then became a communal team back-up after Stewart came through the Budweiser Shootout unscathed - with his Shootout car then becoming his own back-up machine.

"This one is junk," Newman reflected. "The right rear just exploded between one and two. It gave me 100 yards of sign that it might and then there was a vibration and I was getting ready to come in but it was too late.

"Unfortunately I took out my team-mate but I don't know who else was caught up in it. I'm disappointed in the situation that Goodyear has put us in. I don't want to be in this situation and it's hard to talk about but we'll do what we can."

Stewart will revert to the car he took to third in the Shootout car for big race on Sunday but he was less than impressed with the cause of the incident. (See separate story HERE).

Stewart had been due to start the 500 from fifth on the grid, while Newman was due to start 36th.