I have the 10' air tired version which is ohso much more comfy.
I've had it for about 3 years. Been awhile since I rode it so I took my 1lb. portable tank and off I went. 30+ miles. Those 1lb. tanks retail for about $3 new. Now here's the trick...http://compare.ebay.com/like/2307559353 ... s&var=sbar
You can get #25 "BBQ" tanks and refill them and save alot
of moolah this way. I went further and bought at my local propane dealer a #40 tank.
Combustion of propane gas yields carbon dioxide and water vapor. The only downside, is the little 25cc engine does not produce the torque forces to conquer certain hill gradients so some kicking is required for the steeper hills. On flat and no wind, my 175 lbs. and 8/80 sprocket ratio gets me about 25mph.