All this travelling light business is really overated IMHO. I mean, arriving at a campsite without Gin, Tonic, Glass, olives etc. just lacks a certain something. The sidecar helps of course
On the tube thing I think it is equally a worry what some people don't carry over what they do. I've met plenty in Europe and just beyond carrying a single tube because someone told them it was the thing to do, but with no idea how easy it is to change. The same guys who expect to fit a 21" tube into their 17" rear without ever practiceing at home (and without pinching it) will be carrying a chain and sprockets for a 3 week ride
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because it's on a list they read for a RTW. The G-clamp I carry for dealing with awkward tyre beads (doubles as a vice) probably weighs less and a bottle of slime (or RAC card) would be just as much use to the unpracticed.
Water is another good one. 10 litres per person per day is fine away from civilisation, but why do I see riders getting on the ferry to Spain with full water bottles (although those panniers with the tank build in could be a useful way to shift a gallon or three of dago red on the way home). Lugging 10kg of English water then drinking coca cola all the way can't be the way to do it
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(not that I drink the stuff, prefer the whisky neat, although tea would taste better I'm told). Too many people just wanting to say they own a camelbak or Sigg bottle, or not understanding what their own kit is for? The empty Camelbak weighs something similar to a 300ml plastic bottle bungeed to the rack and will be fine until you start buying litre bottles a week later? Up to each person of course, I'd stop to use a Camelbak tube anyway (uncontrolled drinks risk putting my pipe out).
I think I'd rather see inexperienced riders with piles of stuff while they make their lists of what they personally didn't need/can't use, the people doing big trips after a lot of practice having exactly what they need (and no more) and us semi-alchoholic, food obsessed, pipe smoking types safe on our outfits doing it Victorian explorer style. It's whatever makes your trip.
Got to do now, time for tiffin,
Andy