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Old July 20th 18, 05:20 PM posted to rec.bicycles.tech
JBeattie
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Posts: 5,870
Default Making America into Amsterdam

On Thursday, July 19, 2018 at 11:34:53 PM UTC-7, wrote:
On Thursday, July 19, 2018 at 8:59:16 PM UTC+2, Frank Krygowski wrote:
On 7/19/2018 2:13 AM, wrote:
On Wednesday, July 18, 2018 at 11:08:23 PM UTC+2, Frank Krygowski wrote:
On 7/18/2018 12:15 PM, jbeattie wrote:

I spit on tiny clown pumps -- no, I mean it. Sometimes the pump-handle/piston needs lubrication. I prefer the hose models, but all of them are a PITA and require about 200 strokes to get a tire up to pressure.

I also carry CO2 cartridges and used both the pump and the cartridges last weekend due to a flat-fest with my son. I buy cheap cartridges in bulk from Amazon. Yes, the environmental impact of steel cartridges is bad . . . but they're so convenient! I scoffed at them until I started using them, but I would not go with CO2 alone. I always carry a pump.

A couple years ago, after some health problems, I went on a club ride
that was nearly too much for me. It was very hot, and I think my recent
bronchitis was still constricting my breathing. I was fighting to keep up.

As we were climbing on one of the more remote roads around here, one guy
flatted. Normally I'm one of the chief flat fixers, but I lay my bike
down, then lay myself down on its downhill side and propped my feet up
on the handlebars, trying to get some strength back.

Lucky for me, the repair was a disaster. They put in one spare tube, but
it was leaking badly. They put another tube in and tried inflating it
with CO2. The CO2 fitting somehow misfired. They wasted another CO2....
and so on.

I finally got up and gave them my full-size Zefal pump, the only
inflating device I ever carry. (Except on the folding bike, where I
have a mini pump stashed.)

They succeeded with the Zefal. And I had recovered enough that I was OK
the rest of the ride, and perfect after a Dairy Queen stop for a bunch
of Mountain Dew.

I think if I were to carry anything else on the bike, it would be
Mountain Dew.

--
- Frank Krygowski

My experience is just the opposite. A common mistake people make with CO2 cartridges is that the fill their tire in one blow. The valve will freeze if there is some humidity in the air. Better is to fill your tire in 3 or 4 blows and wait a couple of seconds in between. people should have paid attention during science class ;-)

https://en.wikipedia.org/wiki/Adiabatic_process

I know about adiabatic processes, and it's obvious the temperature of
the expanding CO2 will drop. But I have no personal experience with CO2
tire inflaters. Are you saying the inside of the valve freezes? Can you
explain how that happens?

It seems to me the CO2 being injected must be dry, and the tube is
essentially empty of air. I'd think if ice formed, it would be on the
outside of the valve where it doesn't matter.

--
- Frank Krygowski


Good question but somehow some moisture gets in and freezes the valve stuck. There is a relation between the relative humidity and the occurence of a stuck valve. It can be solved by warming the valve by holding it between your fingers for a couple of seconds.


I get freezing on the valve, but I've never had a problem with getting a complete fill with a single "shot." I use a PDW Shiny Object that has a screw valve. https://ridepdw.com/products/shiny-o...nt=24673864833 You can start with a low flow and then ramp it up. https://cdn.shopify.com/s/files/1/14...879473743 691 I typically just open the valve and let it go.

-- Jay Beattie.
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