Can't say that i have ever had trouble with tubes, so i guess you guys got some extreme situations going on??
I also definitely can't agree on tubes costing 1/3 of the cost of a new tire. Where in the da world are you buying tubes??? LOL... Last tubes i bought cost around $18 each for good quality ones. As for the moisture problem, i just popped off a tire to get a nail out of it, went through the tire and the tube, patched the tube and tire and put it back together. The beads are shot on the wheel but with a tube its been fine for something like 15 years now, there is still no rust inside, looks the same as it did when i put the tube in there for the guy 15 years ago, the talcum powder i sprinkle in to allow the tube to expand without sticking somewhere was still in there as well, dust came falling out!
Now if you ride through mud and water a lot, then yeah a tube could be an issue if your bead isn't sealed and water gets in, but i haven't had that issue myself. I detest tire slime or any other crap like that, usually when i get one with that stuff in it i have to toss it and find a new one because its shot. That stuff should be put in for one reason, in an emergency to get home or to a tire shop, but not left in there. Tire slime, fix a flat, all that stuff is last ditch effort get home crap and its not worth the money it costs.
Each to his own, but i have some tires with tubes in them, and i have never had a single issue with them. I helped take off some tractor tires that had tubes in them, they were on for 40+ years... Guess what, no rust issues... So i guess its dependent on the use of the machine.
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1984 Honda ATC200ES "Big Red"
1982 ATC200E "Hondie"
1988 TRX300FW "Project Quad" Still in progress....