I ride an EZ 1. Best purchase I ever made. I got it used on EBay and never had a single regret. I've probably put 2000 miles on it since I bought it, and all I have done is wear out the seat cover. Super comfortable, reasonably fast (I am a Bicycle Vehicularist), and gets a lot of positive attention. $350.00 is a steal if it's in rideable shape.
Why do you want to change the tires? The small wheels make for a great ride, and they seem to be a bit tougher than 26" or 700 cc wheels. I ride off road often (though nothing very technical...I mainly just do 2-wheel hiking and camping) and the smaller wheels handle the rough very well. For commuting, distance riding, and general use, there is nothing better.
The only drawback I had was having to buy another indoor trainer that it would fit, for when the weather is less than desirable. I had to get a CylceOps Mag Trainer, and an adapter for 20" rear wheels. All told, it was only around $95.00 for both, on EBay, so it was not that bad, and now, my wife even rides the EZ indoors, and she hates riding regular bikes.
'Bents do require you to adjust your riding style a little, but it's nothing serious. You cannot stand on the pedals to climb hills, but the seat back gives you extra leverage as you push forward on the pedals, so it is easier to spin up hills than on a regular bike, even if not as fast. I am never in a hurry, so it's not a problem with me. As long as I get there, that's all that matters. Personally, I think climbing hills with the EZ is easier than with a conventional bike. I don't seem to have near as much trouble, or get as out-of-breath, even loaded down, or pulling my trailer. .
I have had no regrets at all buying the EZ. I sold 8 of my other bikes (I did keep my favorite Mountain Bike, just for when I feel a little wild....), and I like the EZ so much that I am seriously considering getting a trike, if the Mrs will let me. My riding distance and time has increased over 100% since I got the EZ. In fact, I seldom drive anymore, unless it is absolutely necessary. The EZ put the fun back into riding. No sore butt, no numb hands or crotch. and really no need for special bike clothes anymore.
I really don't understand why recumbents are not more popular. They are such more practical than a conventional bike for general use, imho.
Hope this helps....
Last edited by Schwinnhund; 11-03-15 at 01:03 AM.