Tires on many aircraft do not wear evenly. On Cessnas, for instance, the tires are hanging at the end of a spring-steel strut, and the tire's vertical axis orientation depends on how much load is on the gear.
Fly Babies, while they have stiff landing gear, see the same sort of wear. Due to both landing loads and the pull from the flying wires, the ends of the axles tend to bend upwards slightly. This makes the inside of the tires wear faster than the outside.
This is pretty common in Fly Babies...and doesn't seem to cause any problems. The axle bends a bit, and tends to keep the new angle.
If you just swap the entire wheel assembly from left to right, you don't gain much. The same side of the tire is still on the inside, hence a similar wear pattern continues.
To maximize your tire life, you need to remove the wheel from the airplane, disassemble the wheel, remove the tube, then flip the tire over and reassemble with the more-worn section to the OUTSIDE of the wheel.
If the tube gets pinched anywhere when you put the wheel back together, it'll develop a leak. Reassembly is best accomplished with clouds of talcum powder (e.g., "baby powder") as a lubricant. Shoot the inside of the tire with the powder, then stick the tube back in. Make sure the inner radius of the tube is nice and powdery, then reassemble the wheel. Shift things around as the wheel's mating surfaces rejoin to make sure you aren't pinching the tube.
Attach the two wheel halves together (with the bolts, snap rings, etc.) then *partially* inflate the tube. Then deflate it, install the valve core, and run the pressure up to normal. With the talcum powder inside the tire, this'll let the tube shift slightly if it's a bit off-center.
While you have the wheel off the airplane, you might as well grease the bearings. Real mechanics have a fancy bearing greaser. The rest of the skinned-knuckle brigade gets by with a tub of bearing grease from the local NAPA store.
Clean off the exterior of the bearing and set it on a clean paper towel with the wider-diameter side up. Grab a dollop of grease and put it in the palm of your left hand (or right hand, if you're left handed).
Then pick up the bearing with your clean (clean? Ha!) hand andshove the tapered part of the bearing (where all the little rollers are) into the grease in your palm. You're trying to shove grease into the gaps on the sides of the rollers. Rotate the bearing slightly, and shove a new section into the grease. Work your way around (you might have to renew...or at least, re-pile...the grease in your palm), then re-install the bearing.
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