TOTW: Check your tire pressure, at least weekly

The riding tips on these pages are my personal opinion about matters related to motorcycle riding. They are not the official position of any organization, and are for your consideration only. They are not hard and fast rules, they should not necessarily be applied in all circumstances, and they should not be applied without thinking. Always use your judgement and take all current safety factors into account while riding. You are responsible for your riding, not anyone else (especially me). These tips were originally published by a motorcycle riding course, called “Tip of the Week” (the reason for the TOTW in the titles).

Tire pressure is critical

Your tires are a critical part of your motorcycle’s suspension, and the most important component of your traction. If you think about it, your bike is actually touching the earth only at the “contact patches” — the two spots where your front and rear tires touch the ground — at most a couple of dozen square centimetres.

Tire design assumes a fairly narrow range of inflation pressure for proper response. Tire pressure changes with use, age, and temperature. (And, of course, leaks.) If your tire pressure is so important, and can change so easily, it’s critical that you check it regularly. If you do no other mechanical work on your bike, you should check your tire pressure (and your oil) frequently.

Incorrect tire pressure reduces traction and stability. This will affect your cornering ability and reduce your ability to brake to a stop in a short distance. Incorrectly inflated tires will wear out more quickly and are much more likely to develop a leak, or even a blow-out, endangering you while riding. Although you shouldn’t, you can drive a car with improper tire pressures and not notice (How many times have you seen someone, possibly yourself, who didn’t know they had a flat until someone told them?), while on a motorcycle it will cause serious problems

Service managers tell us that a surprisingly large number of riders bring them bikes with tire pressures far below the correct value, and obviously never check it. This is a safety hazard and causes them to put much more money into replacement tires than is necessary.

Keeping it correct

Get a good quality tire pressure gauge. Make this the only tool you buy if you’re not interested in mechanics. Take good care of your gauge — don’t have it clanging around loose in your trunk.

Form the habit of checking your pressure at least weekly, and before any long ride. Check the pressure when the tires are cold; e.g. first thing in the morning, not at the end of a ride. Check it every morning during a multi-day motorcycle tour. The correct pressure will be specified in your owner’s manual or by the tire manufacturer. Two important notes on the correct pressure for your tires:

  • Unlike cars, most bikes require different pressures in the front and rear tires — less in the front. Don’t be fooled by reading the recommended pressure for one tire and then setting them both to that value.
  • Get the pressure specification from your owners’ manual, or from the tire manufacturer for non-stock tires. The pressures stamped on your tires’ sidewalls may be the maximum safe pressure rather than the recommended pressure, depending on the brand. Don’t assume it’s the recommended pressure.

There’s no point in checking the pressure unless you are able to adjust it. A gas station air pump will work fine, but there is a risk that you won’t bother with the stop for a minor correction. On the other hand, a simple bicycle pump is quite sufficient to correct a small error in pressure, so you might consider having one on hand. Highly portable bicycle pumps that will fit in your touring bag are not expensive.

Space is cramped around the valve on many motorcycle tires. Make sure you can actually fit your gauge and your air pump hose over the valve before you need to use them. For example, the air hoses with long brass filler nozzles, like the one to the left, that are common in many large truck stops won’t fit in the available space in some motorcycle wheels. Better to find this out before you are desperately seeking air.

If you make any major changes to the load on your bike (e.g. riding with gear and a passenger when you normally do not) you may need to adjust your tire pressure, increasing it slightly. Consult your owners’ manual. As a rule of thumb, if the owners’ manual does not give directions, the hot pressure (after riding for 30 minutes) should only be 10% greater than the cold pressure. More than that and you are probably under-inflated, less than that and you may be over-inflated.

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