Thanks for the feedback. It was worth the time to ask.
I guess my next question is, "What is the toughest tube available?"
My primary riding purpose is fitness, so I'm not worried about saving 7 oz on something like a tube. If it is thicker and will last longer, I'm all for it.
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Current bikes: Unknown year Specialized (rigid F & R) Hardrock, '80's era Cannondale police bike; '03 Schwinn mongrel MTB; '03 Specialized Hard Rock (the wife's)
Gone away: '97 Diamondback Topanga SE, '97 Giant ATX 840 project bike; '01 Giant TCR1 SL; and a truckload of miscellaneous bikes used up by the kids and grand-kids
Status quo is the mental bastion of the intellectually lethargic...