Changing Main Gear Tires

From Matronics

A. Dennis Savarese (dsavarese AT elmore DOT rr DOT com)

Disassembly

1- Remove the wheel assembly from the airplane

2- Deflate the tire by removing the valve core

3- Look at the valve stem and you will see a nut and washer holding the valve stem in place on the rim. Remove the nut and washer.

4- Use two large screwdrivers or similar tools, insert the screwdriver or tool between the tire and outside rim. Press down on the screwdriver to release the tire bead from the rim. Do this in several locations around the rim until the bead has broken away from the rim. Repeat for the other side of the rim and tire.

5- Once both the top and bottom tire beads have been broken away from the rim, place the wheel assembly on a suitable pad with the brake drum down. Now press the outside of rim down. The two large semi-circular clips will release between the rim and the hub. Remove the clips noting precisely which way you removed them. They are not the same length from the notch to the end in both directions. It is important when reassembling the rim to make sure one end of the clip is NOT extending over the valve stem area.

6- After the clips are removed, lift the outer rim up and away from the hub. Next lift the tire and tube up and away from the hub. There should be a thin metal sleeve over the valve stem. It has a 90 degree bend at the top with a hole in it for the valve stem.

Reassembly

7- Spread talcum powder or similar inside the new tire. This will allow the tube to slide uniformly inside the tire when you inflate it.

8- Find the red dot on the new tire. Insert the tube and align the valve stem with the red dot on the new tire. Remove the valve core from the new tube. Inflate the tube in the new tire to evenly spread the tube inside the new tire. Allow the tube to deflate. Again, check the alignment of the valve stem on the tube to the red dot. Be sure to keep the rubber valve stem guard on the tube.

9- Spray some soapy water on the beads of the tire.

10- With the valve stem up, place the new tire and tube over the hub.

11- Next place the outer rim over the hub, being sure you align the notches of the rim to the hub. These are for the big clips to fit into. Once again, check the alignment of the valve stem to the red dot on the tire. Realign if necessary.

12- Place the metal sleeve back over the valve stem.

13- Place the washer and screw the nut loosely onto the valve stem.

14- Place the large clips on the rim making sure one end does not cover the opening of the valve stem. The clip should not protrude at all into the valve stem cavity.

15- Press down firmly on the outer rim and while doing so press the large clips in place. Once in place they will lock the rim to the hub.

16- Insert the valve core into the valve stem.

17- Inflate the tire making sure the clips seat properly between the rim and hub.

18- Tighten the nut on the valve stem to allow the valve stem to protrude approximately 1/2" or above the nut.