The Neighbourhood Mechanic: Pressure check

The second best thing you can do to maintain your car in reasonable condition is to maintain tire pressures. The first being regular oil changes. You've heard it many times in this column, “tires are the only thing between you and the road.” Low tire pressures not only cause handling issues, braking issues, and premature tire wear, running on underinflated tires cost you money. Pushing a flat tire down the road will cause you to use more fuel. Fact: tires will lose up to one pound of inflation each month. Just like the deflating party balloon, there are no holes yet the air escapes. Cold weather also has the effect of reducing tire pressures. Be smart, invest in a tire gauge and don't be afraid to use it.

Q. Are there any drawbacks to using CO2 to inflate tires? There is a product on the shelves where a small regulator is attached to a CO2 bottle supposedly enough to fill three 13” tires and with a coiled, flexible hose attached to which one would attach the tire inflator. I'm wondering if mixing air with CO2 would pose a hazard or if the tire was inflated totally with CO2 would be a problem. This product appears to be the ideal “emergency” kit when on vacation should one be unfortunate enough to have a flat.

A. The latest trend in tire inflation is to remove oxygen from the equation. This is done by charging the tires with nitrogen. Oxygen encourages the degradation of the rubber and has a tendency to expand more dramatically as the tire warms up. By switching to nitrogen tire pressures are more stable. Using CO2 does not remove the oxygen from the charge so I would assume it can't be more harmful than straight air. I would also think that CO2 fill is just a temporary measure and when the tire is repaired you use the proper alternative.