Inflating Tyres Safely
Today’s Passenger and R.V. tyres, are tubeless. In order to get the beads to seat and seal, specialised equipment is needed, with a blast of air into the tyre casing, sufficient to move the beads outwards till they contact the rim. Virtually the only way this can be done without this equipment, is to fit a tube, and pump away till the tube walls do the job for you. That is why dedicated off-roaders always carry a spare tube, tyre levers, a pump, and if they are wise and experienced, some tyre lubricant.
So assuming that the tyre is still inflated, and only needs a top-up, it’s down to the local servo you go. Join the queue (you can feel virtuous because they’re probably won’t be one). Uncoil the hose from its stand. Unscrew the valve cap, give the valve a blast of air by depressing the trigger and the stem in the centre of the airhose to clean the area of the valve. Unscrew the metal or plastic valve cap, and top up the air pressure. Then on the first tyre of the set that you do, check the pressure against the gauge that you carry in the glovebox. After that, move on to the next wheel, but not before you have screwed the valve cap back on.
That’s your first line of defence against air loss.
It’s surprising the number of motorists who realise that they have a slow air leak a week or so after they have topped up their tyres. Commonly, dirt under the valve stem is the problem. Detect this with “the spit application test”. If a blob of glottal applied with the finger over the valve orifice bubbles, then the valve core needs replacing. It only costs a few cents, but a slotted valve cap, or core removal tool, is needed. Ask your friendly service station operator for help, because the tyre has to be almost deflated, unless he’s quick!
Entry filed under: Tyre safety & maintenance.