AKRON, Ohio - No need to get rid of that spare tire, but radial tire "love handles" are misleading indicators of tire inflation and performance.

Still, many motorists visually rely on the size of the bulges near the road surface to determine whether a tire is inflated correctly, according to engineers at Goodyear.

Only a quality tire pressure gauge will do, said Bill Egan, chief engineer of advanced product design. In the winter, check tire pressure frequently, with every change in the weather to maintain proper inflation.

In a radial tire's case, "love handles" aren't due to lack of exercise. They occur naturally. However, some new radials on the market have won the battle of the bulge, Egan said.

Goodyear's new run-flat tire lines, for example, don't exhibit the customary radial bulge. Although they are radial tires, the reinforced sidewalls keep them from deflecting in the same manner as conventional radial tires, Egan said.

"The bulge in the lower sidewall adjacent to the tread is inherent in the way a conventional radial tire deflects. This area is the least rigid and is adjacent to the most rigid, the tread. In run-flat tires, the differences in rigidity between the sidewall and tread are not as significant as in normal tires," he said.

In conventional tires, visually inspecting the shape and size of the bulge is not viable, particularly with changing winter temperatures, he said. Ambient temperatures affect tire inflation pressures; cold air is more dense than warm air, automatically reducing a tire's pressure.

For example, a tire inflated at 32 pounds per square inch at 70 degrees will drop to 26 psi at freezing.

An underinflated tire reduces fuel economy, shortens tire life and reduces snow traction. The underinflation also makes those "love handles" grow, Egan said, but not enough to be noticeable.