LANDING GEAR SHIMMY

[Jim B]

Hi to all
I converted from tail dragger to tri gear 5 years ago and never had a problem with shimmy. Recently on take off and landing I started getting a shimmy. With the plane on blocks, I looked at the nose gear and main gear legs. I found very little play in any of the wheel bearing and nose gear bearings. The nose gear is straight. I did find slop in the push rod to nose gear arm and put additional washer on the clevis pin to reduce the play. This lead me to think the tires maybe out of balance so I looked at them. They need to be replaced because the center of the thread is almost all gone in some areas of the tires. Out of curiosity, I added up the number of landing I had on the tires and was surprised to see they had 626 landings. So my question to you, How many landings do you get out of a set of tires?
Jim

[wlarson861]

With the toe in on the tail dragger mains I usually get a little over a two years worth of landings before they need replacing so about 200 to 300 landings. If you have over 600 landings I'd say you got your money's worth.

[Jim B]

Bill
I was also getting 300 landings per set of tires in the tail dragger configuration. I was just really surprised at that many landing in the tri gear configuration.
Jim

[peter anson]

Hi Jim, I think it depends largely on the landing surface. Grass runways are very gentle on tyres. My original Cheng Shins lasted 480 landings, probably 80% on sealed runways and 20% on gravel or grass. Correct toe-in is also really important. I noticed that my new tyres were heavily worn after only 40 landings, and found that the alignment was incorrect; one wheel now had zero toe-in and the other was slightly toe-out. It turned out that I had bent the gear legs slightly doing a poor landing in "challenging" conditions.

Peter
Sonex 894

[Jim B]

Just to close the loop on the shimmy, I did replace all three tires and tubes and no more shimmy.
Jim