McCarron: Consumers must pay price for need for speed

I recently received an email from a reader asking for clarification on the complicated rules about mounting speed-rated tires that differ from the OEM specification — and I found a complicated answer.

The question is: If a customer's vehicle comes OE with H-rated tires, but the customer doesn't want to spend the money to buy another H-rated tire, what are the dealer's liabilities when replacing with lower speed-rated tires?

A couple of tire makers I contacted suggested referring to the tire fitment guide recommendations.

Michelin North America Inc. recommends that the speed rating of the replacement tire be equal to or higher than that specified on vehicle placard.

I spoke with one of Michelin's tire experts who admitted that there are dealers out there who acquiesce to consumers' requests to downgrade the speed-rated tires on their vehicles and noted that speed indexes have been evolving very rapidly on tires, much more rapidly than speed limits on the road.

Some light truck tires may be S-rated (112 mph) or even R-rated (106 mph), but he advises against replacing R-, S-, T- (118 mph) or H- (130 mph) rated tires with a lower speed-rated tire.

There is actually a trend toward upgrading to H-rated tires, as T-rated tires are becoming less common, and replacing a T-rated tire with an H-rated tire. That's not a problem, he said.

"At Michelin, we're bumping everything we can to an H-rated tire," he said.

High-performance tires, those rated V, W, Y or Z, are usually found on sportscars — Chevy Camaro or Corvette, Ford GT or Mustang, any Porsche model, high-end Acuras, etc.

"They need to pay to play. They need to replace that tire with the exact speed rating on there," he said, adding tongue-in-cheek, that "if on the high end, you don't want to pay that (tire) price, you should not have bought that car."

These tires are designed for a lot of handling and a lot of speed, and so switching speed ratings is not recommended.

"If a Michelin dealer replaced a W-rated tire with a V, we'd be pretty upset," he said.

Now some mid-level car models, such as the Honda Accord Sport and the Toyota Camry Sport, are outfitted with V-rated tires for appearance sake, he said. A V-rated tire would allow the driver to run the car up to 149 mph for a short period of time.

"I don't know anybody that owns an Accord or a Camry that goes over 100. This was more cosmetic than anything else," he said.

If tires with a lower speed rating are requested or selected, then the top speed of the vehicle must be limited to such lower speed limits. The customer must be informed of the lower speed rating, he advised.

When a customer requests replacement tires with a speed rating lower than that specified on the vehicle placard, the dealer must advise the customer that the handling of the vehicle may be affected and the vehicle's maximum speed capability is limited to the lower speed rating of the new tire installed on the vehicle.

It might be wise to have these customers sign a document stating that these requirements have been explained to them.

Of course, practically speaking, vehicle owners likely can't guarantee the vehicle won't exceed the speed rating if they loan their vehicles to other drivers.

So in the end, a dealer's best bet is to stick to the recommendation on the vehicle placard and avoid potential grief.

If you have a tire service question, email Tire Business at [email protected] and let us help you find an answer.