I had a hard landing a couple of months ago. It was a combination of low vis and target fixation. The nose wheel came down hard.

I pulled the cowl the and checked mounts, puck system and anything else I could think of. I lifted the nose and spun the tire. Everything looked fine and I counted myself lucky. I was soon to find out it wasn't.

Since then I had 3 or 4 flights with no issues. This past weekend my nose tire had lost air - it was noticeably low. There was obviously something wrong because I had replaced the tire and tube about 4 months ago and it had never lost any air.

So I went to pull the wheel and my first issue was that I could not get the axle to slide out of the hub. This meant I couldn't get the nose wheel off the plane. Then I spun the tire and looked closely from the front of the plane. The tire was clearly spinning out of round. Apparently I didn't check for an out-of-round issue when I spun it in my initial inspection. 

Looking closely at the bearings I could see what looked like a very slight deflection in them. Again, I missed this on my initial inspection. 

I ended up pulling the nose fork off the plane. Even on the bench I could not force the axle out of the wheel. I ended cutting the axle out with a grinder. 

Either the axle was bent or the bearings damaged, or both. So, I ordered a new axle, axle nuts and bearings. 

Today I removed the tube from the tire to locate the source of the air leak. The tube had a clear indention from something pushing on it. Looking inside the tire I found two small junks of metal. My first thought was that I had somehow left these in there during the initial install.

Then I took a closer like at the wheel halves. Each wheel half had a chip of metal missing, on the inside portion. This was impossible to see without disassembly. 

So the wheel chips rubbed on the tube and caused the air leak. I have now ordered a new tube and new wheel halves. 

If I had just checked to see that the tire was just not spinning free, but also in-round, I would have detected a problem right after it happened. At the time I just looked at it from the side and it spun fine with no unusual sound.

What I didn't do was look at it from the FRONT to see if it was still in round when spinning. You couldn't tell from looking at it from the side. 

I got lucky that the tire didn't go flat in the air. All in all this was a fairly inexpensive fix and a few good lessons learned.

My take-aways:

1. Don't be stupid when landing,

2. Look at a tire from the front to detect an out-of-round condition.

3. Disassemble the front wheel after a hard landing to detect any internal damage to the wheel. 

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Great report and advice, Gary - thanks!  Some of the Zenith models have Matco wheels that are spun aluminum with radiused inner flanges where the wheel halves meet:

I don't see how this design could chip like your wheel did but I agree with you it's better to err on the side of caution and do a complete breakdown and inspection if external damage is evident and/or the wheel is out of round.

John

N750A

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