screw more psi in the tires.

[BailOut]

This is one of those charged topics that seems to repeat every six months or so, and though I endure lots of negative feedback every time I feel it is important to separate fact from fiction and fantasy from reality. Before I begin it is wise to understand 3 things:

1) Tire companies are one of the worst places to get information about their products. The same holds true of any other manufacturer of consumable goods. While they have to do enough to meet minimum safety standards and product longevity everything is secondary to their primary goal of selling you more of said product through repeated need.

2) Automobile manufacturer's tests for tire pressure are aimed primarily and almost wholly at passenger comfort rather than accident avoidance, product longevity or fuel efficiency.

3) Much of what is considered "common knowledge" concerning tires and tire performance is based on older tire formats and manufacturing principles, and has been negated by newer materials and newer processes.

With those 3 things in mind the rest of what I am about to say makes more sense. It is not just me speaking here, either, but the collective experience of over 6 million miles of road testing by hypermilers and/or hybrid owners.

- The OP's experience with just a few extra PSI causing center tire wear does not ring true as steel belted radials (today's manufacturing standard) do not change shape much at differing pressures, especially with minuscule changes like 3 PSI. His issue is likely caused by his driving style or a manufacturing defect.

- Most folks seem to have difficulty understanding how higher pressures increase traction but it truly is a simple concept. Even at 60 PSI (which I run year round) the contact patch is still large. It is indeed decreased a few percentage points from the original contact patch but not by much overall, and what I gain is greatly increased sidewall stiffness. I commute a twisting, winding mountain road and at the stock pressure of 32 PSI I experience an effect I call "tire side roll", where the sidewall of the outside tire buckles and causes general instability. This is not fun in a hairpin turn at 8,000 feet. At higher pressure I rail the corners without issue, even at higher speeds. It is also worth noting that I live and commute in an area that sees 400 inches of precipitation and hosts 13 ski areas. While not everyone commutes mountain roads every day your car experiences the exact same forces during accident avoidance maneuvering, which is the best safety technique for our small car.

- Tire longevity has increased for every one of us that run much higher pressures. This also makes sense as tires have less rolling resistance at higher pressure. This comes back to the contact patch being slightly smaller. If the tire is fricting on the road slightly less each rotation then it is also wearing down more slowly. I am now at 25k miles on my second set of tires on my Yaris (Yokohama Avid TRZ) and they show no signs of excessive nor uneven wear.

- The MPG gain with higher pressure scales with your driving technique. Someone that normally only gets 32 MPG will not see large gains with higher pressures (though there still will be gains) but for a hypermiler it is an integral part of the advanced techniques. Engine off coasting, pulse & glide, DFCO etc. all greatly benefit with higher maintained speed and longer coasting distances, so much so that I can tell when I have low pressure in a tire just from the loss in my coasting distances and speeds.