Dropping to H-rated tire for winter not a problem

Q: I have a 2009 Nissan Maxima with P225/45R18 Goodyear tires that are V-rated. I am in the process of shopping for winter tires and rims, and continue to receive conflicting information on staying with a V-rated tire or moving to an H-rated tire.

I am trying to understand how the car will perform if I move to an H-rated tire. The common response I receive is that you don't drive the same in the winter and therefore you don't need the additional speed rating. I find it hard to believe the only reason you would need a V-rated tire is for the speed rating.

A: For the winter, there should not be any problem in moving from a V-rating to an H-rating. Most winter tires are Q- and T-rated, even further down the speed chain.

The higher speed ratings are really a measure of a tire's ability to dissipate heat and a measure of its stiffness. These are issues that are not at the forefront in winter driving.

I doubt you will be able to feel the difference in winter driving between a V and an H. Both tires are very stiff. That stiffness gives the Maxima its quick steering reaction. Feeling loss will be negligible.

Q: We have a Toyota Venza, which was newly introduced last year. It is difficult to find a set of P245/55R19 winter tires.

The dealership introduced us to the P245/65R17 Michelin X-Ice 2. They don't carry any 19-inchers, and said it would be safer with the rim size down a couple of inches. Is that correct?

My husband uses the car to commute to the city daily. My son may use it to go to ski resorts in winter. The car is an all-wheel drive with 4.0 L engine.

A: Your Toyota dealer is quite correct – you can downsize to 17-inch wheels and tires. The Michelin X-Ice Xi2 is a great choice, so get it now before they run out of stock.

In downsizing to winter tires, it is important to keep the overall diameter of the wheel and tire the same as the OE fitment. Both these tires are within 0.1 of an inch perfect.

As for "safer," the dealer is stretching this a little. Generally when you downsize, the tire's diameter stays the same but the tires get narrower. Being narrower makes the tire dig down deeper. In this case both the 19- and the 17-inch tires are the same 245 mm width, so you are not gaining any traction. But there is no other narrower alternative.

Email tire questions to John Mahler at thetireguy_1@hotmail.com. Please include vehicle's make, model and year, tire brand and size, as well as your name, address and phone number.