Taxying in after a short flight in our Piel Emeraude, the left tire went flat, so I removed the tire, replaced the tube, fitted the tire, cleaned up the tools, then noticed the right tire was almost flat! Having used my only spare tube, I was able to bring a cylinder of compressed air to the aircraft and get enough air into the tire to be able to quickly taxi to the hangar, put the aircraft away, and jack up the wheel ready for repair.
The first flat was a leaky patch repair. The second was a pinhole leak in the tube.
I'm using Aerotrainer 500x5 tires and butyl tubes from Desser, and have had a number of similar pin-hole type failures over the last few years in that aircraft. In fact, I've had more similar tire failures in this aircraft with those tires than I've had in all the other flying I've done in all types (some of those 18 wheelers!) combined!
The inside of the tire has ridges evident at about 45 degrees to the circumference of the tire, and these leave noticeable impressions in the tubes. It is in this area that pin hole leaks occur.
I've spoken to a number of tire experts to try to locate the problem, and the only thing left is that I'm using too low a tire pressure. I use 25 psi, but I'm thinking that I might up them a few psi.
Any thoughts, anyone?