Like snipe hunts, the subject of winter air in tires is always good for a laugh. Of course, this is the time of year that winter-air salespeople do their best work because waking up to flat tires on a cold morning is a pretty common occurrence in many parts of the country. Snipe hunts happen because the group plays along and eventually it starts to make sense. Members of the Winter Air Society, or WAC, use the same tactics to prey on fleets with a variety of solutions to this problem.
In areas where the early morning temperatures are extremely low, the flat tire will handle like a block of ice, making it impossible to re-inflate it in the field if the beads are unseated. These tires are typically taken indoors, where they eventually warm up to the point where the beads can be reseated. After inflating the tire to the maximum pressure on the sidewall, progressive shops will submerge the assembly in a giant water tank to check for leaks. Mysteriously enough, no bubbles appear — even when the valve stem is moved from side to side. So why was the tire flat?
Temperature has a huge impact on inflation pressure, with every change of 10 degrees leading to an inflation adjustment of 1 psi. If the temperature rises from 50 degrees to 100 degrees, the gauge will read 5 psi higher than the original, or cold, inflation pressure. Likewise, if the temperature drops from 100 degrees down to 10 degrees, the tire will lose 9 psi.
Chicago is synonymous with cold winters, and I can remember one in particular where a series of sub-zero mornings led to an outbreak of flat steer tires. My service techs would leave the trucks on blocks and return a few hours later with the warmed up tires ready to go.
Since it's my goal to put the members of WAC out of business, the only solution to the problem is a cold inflation pressure check when the temperatures are cold, but not too cold. December is the perfect month for checking inflation pressure first thing in the morning because the air inside the tire should be around 32 degrees in most parts of the country, which isn't cold enough to run a high risk of frozen valve cores.
As I've mentioned in the past, if you're not willing to purchase metal inflate-through valve caps, don't bother talking to your tire service provider about a fleet pressure check. I had such a customer and every fall the valve caps on his equipment would disappear so my techs could get to the valve stems. When they found a flat but couldn't find a leak, they would replace the valve stem. Another customer bought the inflate-through caps, rarely had problems in winter, and didn't need valve stems on road service calls. Coincidence? Maybe.
The members of WAC will be out in force after the holidays trying to sell you a wide range of products that will prevent flat tires, irregular wear, and vibrations. In some instances, the slick brochures and distractions cannot overcome the logical solution — a regular inflation pressure maintenance program.
But for most fleets, that's like Santa Claus squeezing down the chimney. Children believe it's possible because their minds are on the presents. Fleets that think they can prevent problems without checking cold inflation pressures might as well wait in front of the fireplace with a glass of milk and a plate of warm cookies.
