In 2005, I bought my first H18, which came with a used Cat trax, probably 10 years old at that point. I added cradles, and used them happily. Then in 2009, I sold that H18 and bought my current H18SX, and continue to this day to happily use the cat trax.
At the beginning of this season, one tyre kept losing air, and each time we went sailing, out came the pump, and we'd inflate enough to launch and return. That became boring, so I called the manufacturers in Florida, who shipped me an inner tube USPS. A local RV/snow-thrower/small machine shop cleaned out the tire and installed the inner tube, and we're good to go.
Dan of Florida and the RV guy both said (correctly) that if the tire is allowed to become deflated, the sidewalls will crack, which is where the leak was. (I had a problem last winter.... another story for another time... which caused this issue).
When I took the wheel off, I was amazed at the simplicity and elegance of the design. Couple of retaining washers and cotter pins, delrin needle bearings... these wheels should last forever.... and they are worth every penny. I look forward to many years of happy rolling....
Suggestion - Over the winter months, keep your cat trax non weight bearing and tires inflated.
1989 Hobie SX18 Sail # 1947
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'