Frugal Flyer: Worn out?

Put the bounce back in your tires

April 1, 2009

How would you like to double the amount of takeoffs and landings you get on your existing aircraft tires? With the cost of even the most modest aircraft tires topping $100 a pair, surely aircraft owners would do all that we can to get the most bounces out of them. So I’m surprised whenever I see an aircraft with tires getting replaced because they’ve been worn almost bare in some areas—yet still have plenty of available tread in others. Simply rotating the tires when they start to wear can allow owners to safely continue flying without buying.

It’s not quite as simple as swapping the left and right wheels. If the tires are wearing faster on the outsides, for example, that would still be the case after you swapped them. Instead, you must take the tires off the wheels and turn them around.

It’s not a difficult job. But it’s a dirty one. And there’s one dangerous aspect: An aircraft tire is a potential bomb as long as it’s got air in it. Tires must be completely deflated as soon as the airplane is safely on jacks. Don’t wait to take the wheel off the axle to deflate it. You might forget. Deflate the tire right away.

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In an ongoing effort to squeeze more flying out of our aviation dollars, AOPA is seeking your tips on frugal flying. Have you found creative ways to operate your aircraft more efficiently? Better manage maintenance, training, hangar, tie-down, or insurance costs? Or buy aviation-related goods in bulk or at lower prices? E-mail the author at dave.hirschman@aopa.org

Most aircraft wheels are split into two identical halves.

Once deflated, the bead can be easily broken and the tire removed and rotated.

This is an excellent time to repack bearings with grease and check brake pads—also tasks that pilot/owners can perform as preventive maintenance under FAR Part 43. When reinstalling the tire, clean the inside and lubricate it with a light dusting of talcum powder. Inflate the inner tube slightly to make sure it doesn’t get folded or pinched when inserting the wheel halves. Align the valve with the red dot on the tire for proper balance. Then connect the wheel bolts (and don’t forget the brake rotor).

Torque the bolts to the manufacturer’s specifications and then inflate the tire to its rated pressure. Deflate the tire again to make sure it’s not binding, and then re-inflate to rated pressure.

Make sure the tires are properly inflated. Too much air pressure will cause uneven wear, reduce traction, and put more stress on the wheels. Too little will shorten tire life and could cause a blowout.

Some manufacturers recommend waiting periods of up to 24 hours before reinstalling the wheels and tires on the aircraft. The installation process usually involves attaching new safety wire to brake calipers and a new cotter pin through each axle.

Unlike automobile tires that list manufacturing dates and locations plainly, aircraft tires have a bizarre, non-intuitive, eight-character numbering system that tells their age and place of manufacture. It goes like this: YJJJNNNN

  • The first number, Y, stands for the year of manufacture.
  • The next three, JJJ, are the Julian date representing the day of the year (up to 365).
  • The next four numbers are the tire identification codes for different factories.

Follow the manufacturer’s specifications and make the proper logbook entries. But wash your hands first. You don’t want that pristine airframe logbook stained with the brake dust, grease, and hydraulic fluid that’s sure to cover your hands.

E-mail the author dave.hirschman@aopa.org.