“Is it true that the speed rating of replacement tires has to be at least the same as the speed rating indicated on the tire placard? ”  

YES. The speed rating printed on the tire placard represents the minimum speed rating for replacement tires. Although it’s fine to install tires with a higher speed rating, installing tires with a lower speed rating is not an option.If all replacement tire sizes must match the sizes printed on the vehicle’s tire placard, why do we put plus-size assemblies on custom wheels?

Remember, the vehicle’s suspension and steering system has been designed specifically for the size tires listed on the placard. Changing tire diameter beyond this point can adversely affect vehicle handling, antilock brake operation, and speedometer accuracy. However, as long as the outside diameter of the original equipment tires is maintained within 3%, the plus-sized custom wheel assembly should not cause any problems.

“Can speed-rated tires be repaired and still maintain their original speed rating?”

It depends on the tire manufacturer. Some manufacturers allow tires to maintain their original speed rating following a proper nail hole repair. Always check the manufacturer’s tire repair policies and inform the customer if any limitations apply.

“Is it necessary to install four snow tires or studded snow tires on front-wheel drive vehicles?”

YES. Front-wheel drive vehicles have a tendency to understeer. This is because most of their weight is concentrated in the front. Installing snow tires on both axles minimizes understeer by providing equal grip at all four corners. Since the weight

If all replacement tire sizes must match the sizes printed on the vehicle’s tire placard, why do we put plus-size assemblies on custom wheels? Remember, the vehicle’s suspension and steering system has been designed specifically for the size tires listed on the placard. Changing tire diameter beyond this point can adversely affect vehicle handling, antilock brake operation, and speedometer accuracy. However, as long as the outside diameter of the original equipment tires is maintained within 3%, the plus-sized custom wheel assembly should not cause any problems.

“Can speed-rated tires be repaired and still maintain their original speed rating?”

It depends on the tire manufacturer. Some manufacturers allow tires to maintain their original speed rating following a proper nail hole repair. Always check the manufacturer’s tire repair policies and inform the customer if any limitations apply.

“Is it necessary to install four snow tires or studded snow tires on front-wheel drive vehicles?”

YES. Front-wheel drive vehicles have a tendency to understeer. This is because most of their weight is concentrated in the front. Installing snow tires on both axles minimizes understeer by providing equal grip at all four corners. Since the weight in a rear-drive vehicle is more evenly distributed, installing two snow tires on the rear axle is acceptable.

“Is it true that the tires on 4WD and AWD vehicles should all be the exact same size and have the same tread pattern?”

Yes, especially where AWD vehicles are concerned. This is because driving on mixed tires can damage drivetrain components due to the difference in circumference between the tires on the front and rear axles. That’s why the tires on these vehicles must be identical, and why maintaining proper inflation pressure is so important. In fact, some vehicle manufacturers strongly recommend replacing tires in complete sets to ensure circumference is the same on both axles.

“Can you mix radial and bias tires on the same vehicle?”

Yes, but it is not recommended. As long as the vehicle is NOT a 4WD or AWD model. On front-wheel and rear-wheel drive vehicles, always install the bias tires on the front and the radial tires on the rear to prevent oversteer.

“Can you mix aspect ratios on the same vehicle?”

Not if the vehicle is a 4WD or AWD model. On front-wheel and rear-wheel drive vehicles, the tires with the lower aspect ratio should be installed on the rear axle to prevent oversteer.

“If you are replacing one tire on a vehicle, where should it be installed?”

Always pair the new tire with the tire that has the most tread depth, and then install both tires on the rear axle (except certain AWD vehicles). Be sure the replacement tire is the same size and construction as the other tires and has an equivalent or higher speed rating.

“What causes some tires to smell like ammonia when the valve core is removed?”

This smell is usually an indication that the tire contains ‘fix-a-flat’ or similar injectable sealant. Since many of these products are flammable, a spark generated within the vicinity of the tire can ignite the gas and cause an explosion. To prevent serious personal injury, it is vital that the gas be purged from the tire whenever an ammonia smell is detected. This can be accomplished by inflating and deflating the tire several times before unseating the beads. If the tire is going to be returned to service, clean the inside of the tire thoroughly, making sure all of the sealant has been removed.     

“What does it mean to ‘double bead’ a tire?”          

The term ‘double bead’ refers to installing both beads simultaneously. This is not an acceptable tire-mounting procedure and should not be attempted.