WASHINGTON (July 6)—Tire inflation pressures up to 25 percent below the vehicle manufacturer's recommended minimum on a 15-passenger van "should not have a substantial adverse effect on its handling," the National Highway Traffic Safety Administration said.
The agency added, however, that underinflation may undermine tire endurance. It also said its study of the effect of tire pressures on the handling of 15-passenger vans can't be taken as authoritative, because only one vehicle—the Ford E-350—was evaluated.
The National Transportation Safety Board had told NHTSA it was concerned that low tire pressures had contributed to rough handling in two 15-passenger-van crashes it investigated.
NHTSA issued the tire pressure/van handling report in conjunction with its third warning in three years about an increased rollover risk under certain conditions in 15-passenger vans. Checking tire pressures and treads every month, the agency said, will help prevent rollovers.