[ExI] Larger diameter inner tube in smaller diameter wheel

[spike]

Spike wrote:
>>... Then it occurred to me: that longer tube might have worked anyway

>...I've done this before and it works fine.  Tires don't stretch enough
with inflation to even feel a lump.

>...As has been said, though, if you're trying to stuff a 559 ("26") inner
tube all the way down into a 406 ("20") wheel, you might want to fold it
over twice so that the extra weight is symmetrically distributed.

>...Note that tubes are much cheaper online than in stores.  JensonUSA
usually has a good selection under $5....JS


Thanks JS.  

One of the extropians suggested the diametrically opposed folds to
counterbalance each other, but I thought of another cool variation on a
theme.  Imagine the valve stem at 0 degrees.  Now arrange the double folds
at about 100 degrees and 260 degrees.  Then the double folds will
counterbalance the Schroeder valve and the tire will be better balanced than
one with the correct tube.  I would pay a slight weight penalty but that
doesn't matter much for a touring bike.  Cool!

Since I am on the topic, I have additional insights to share.  Our own long
lost Amara Graps is a big bicycle fan.  She is alive and well, living in
Latvia.  She is a touring rider.  I may post this forward to her, hoping she
has some comments.  

I have a recumbent bike, which I have owned for over a decade but only
started riding a lot in the past year or so.  Now I ride about 8 miles a
day, which isn't a lot but it's a start.

Imagine you have a weight of any size: 5kg is plenty for this experiment, or
thought experiment.  Hold your elbow at pi/2 so that your humerus is
vertical and the ulna and radius are parallel to the floor with the weight
in your hand.  Hold it there for a few minutes, or until you can't hold it
any longer.  Don't move it, just hold it out there.  There is no work being
done in the physics sense, no force times distance.  There is force, about
50 newtons, but no distance, so no work.  Hold it until your arm is too
tired to hold it any longer.  OK put it down.  Question: how do you feel?
Are you ready to do the same with the other arm?  Or would you prefer to
just sit for a while?  I predict you are tired.  All over, not just that
arm.  Conclusion: holding a muscle tense uses up energy.

OK now apply the lesson learned to bicycles.  When one rides a standard
diamond frame, the back muscles are tense holding up the torso, the neck
muscles must hold up the neck.  So a diamond frame rider uses up energy just
coasting.  But the recumbent rider can relax every muscle except the ones
doing the work.  So I conclude that for very long rides when speed is not
all that important, but energy management is critical, a recumbent might be
your best bet.

Comments or counter evidence please?

spike