Q: Is there any noticeable advantage to inflating tires with pure nitrogen instead of air? Does this result in any improvements in performance or fuel consumption?

I know of an auto dealership that is automatically adding $199 (plus HST) to the cost of all its new vehicles to inflate the tires with nitrogen. Is this really necessary and is this additional cost reasonable?

I have been using regular air for more than 50 years and have found it to be generally satisfactory.

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A: There is much hype about nitrogen, and it is just a lot of hot air. It is a money-maker for dealerships offering to fill your tires for $20, but this $199 is a new high. In addition, it is a ripoff of the highest order. If nitrogen was free, sure I’d use it — why not? But really, it offers so little advantage over compressed air it is not worth one extra dime.

The air we breathe and the air that is compressed in your tires is already 78 per cent nitrogen. Pure nitrogen is used in big commercial aircraft, some long-haul trucks and elite class race cars. In aircraft and race cars, it is used because a pure gas (instead of a mixture of gasses like compressed air) lets the engineers predict exactly how the tire will react when it is stressed by heat. Heat causes the tire to enlarge (we are talking about small amounts here) and so the racing engineers can get optimum pressures.

In aircraft, the tire undergoes tremendous stress: warm at takeoff, deep below freezing at altitude and then back to normal temperatures when the landing gear goes down. The impact of landing creates a huge heat spike. In a situation like this, the engineers need to be able to predict every reaction of the tire.

However, when you are driving down the highway, you don’t need this degree of predictability. On a hot day, your tire will increase pressure by a few PSI. Do you care if it is 2.2 extra PSI or 2.7 psi? If you need that information, then get nitrogen and carry a computer with you to calculate how that affects maximum grip. For most of us, life works fine with compressed air.

The reason compressed air is a little less predictable is that it contains some moisture that was in the air when it was compressed. The water vapour causes the unpredictability. However, most good garages have water traps on their air compressors. If they are functioning and emptied, there will be little water vapour.

Fuel economy depends on maintaining proper air pressure. It does not matter what gas is in the tire. If it is inflated properly, the fuel economy will be the same.

Q: I just replaced the tires on my 10-year-old car. Do I need a wheel alignment, which has not been done on the car?

A: Yes, after 10 years, your car deserves and needs a wheel alignment. It is a good idea to get one whenever you buy new tires. Correctly aligned wheels will maximize the tires’ life by stopping uneven wear patterns. Alignment should also be checked after a major impact on curbs, potholes and the like.

Q: I drive a 2008 Ford Taurus AWD an average of 12,000 km per year. I am older, retired, and don’t venture out in bad weather. I have used Goodyear TripleTreds in the past and they are a terrific tire. However, they tend to be noisy and hard riding. I see that Goodyear Assurance ComforTred offers nearly the same traction in snow, wet and dry, and it seems it may have a quieter, softer ride. Do you have any thoughts on the ComforTred replacing the TripleTred in my situation?

A: The Goodyear TripleTred is an excellent tire. Though it is an all-season rated tire, it does surprisingly well in light snow. The ComforTred is not as good in the snow. I would not make that switch unless the car stayed in the garage when there was snow on the ground. The Goodyear ComforTred is really a traditional all-season tire. And, “traditional” in this sense is code for “three-season” tire.

I highly recommend the ComforTred for people looking for a great ride on their cars. I don’t think it is suitable for snow and I would seriously question anyone who says it is almost as good as the TripleTred.

Got a question about tires? Ask John Mahler at: thetireguy_1@hotmail.com