Copyright 2003, Roadracing World Publishing, Inc.

More details have been learned about the rear tire failure and resulting crash involving Graves Yamaha’s Jason DiSalvo Tuesday during the annual Dunlop tire test at Daytona International Speedway.

According to Yamaha Team Manager Tom Halverson, DiSalvo was on the 11th lap of an 18-lap, full-race-distance (15 race laps, one parade lap, one warm-up lap, one cool-down lap) run when his rear tire blew where NASCAR Turn Four flattens into the adjoining straightaway.

The long run was done not only to look at tire wear but “to see if it had enough fuel to run well on the last lap without sputtering (from fuel starvation),” Halverson told Roadracingworld.com Wednesday morning. “The fuel tank holds 18 liters and the bike uses one liter per lap.”

Halverson said some bikes tend to sputter and run poorly when the fuel level gets low in the tank and the gravitational forces of the Daytona banking work against the bikes’ fuel pumps.

Early reports that DiSalvo’s tire may have been rubbing against his swingarm were incorrect, according to team members, who pointed out they were watching his tires very closely during the long run from various points on the track and would have seen the tire rubbing against the swingarm much sooner than lap 11.

Halverson showed Roadracingworld.com digital pictures he took of tire marks left by DiSalvo’s crashing bike. Starting at the exit of NASCAR Turn Four, tire marks left on the pavement seem to indicate DiSalvo’s tire was hopping. Later marks seem to indicate the bike was weaving violently before the rear tire locked up completely and threw its rider off.

DiSalvo first hit the ground well before the track crossing area on the straightaway between NASCAR Turn Four and the Tri-Oval, which is over 700 feet from the final resting place of his Yamaha, according to Daytona International Speedway personnel. DiSalvo slid for an estimated 150 yards.

In addition to suffering a concussion in his tumble and slide, DiSalvo received friction burns on his back which left clear imprints of the raised edges of his “cool suit” on his skin. Halverson showed Roadracingworld.com pictures of DiSalvo’s back burns.

DiSalvo also suffered burns and abrasions to both hands and had a sore heel. All in all, Halverson said he was impressed with the job done by DiSalvo’s safety gear.

DiSalvo is expected to come to the Speedway Wednesday but is not expected to ride.