| Re: Rim brake heat and clincher blowoff, was Re: Potential good news for Mt. Washington access.
jobst brandt wrote:
> Tom Sherman writes:
>
>> There still needs to be a control for temperature in the static
>> test, since of course compressing air into the tire raises the
>> temperature of the air and casing. However, if the tire is inflated
>> slowly, actual temperature rise will be insignificant.
>
>> In addition to the motion between the tire and rim that Jobst Brandt
>> mentions as possibly affecting blow-off pressure, there is the
>> effect of heating the tire, since the rubber will change properties
>> with temperature.
>
> I don't believe inflating a tire makes enough temperature difference
> to worry about. I have not noticed hot tires from inflation nor even
> a hot hose or brass hose-to-valve coupler (hose chuck). I am aware of
> Silca frame fit pump heads getting hot in the hand while pumping but
> that is a big difference from a floor pump and hose.
>
> I think we are scraping at nits. Besides, who gives a damn how much
> pressure a stationary wheel can hold. We are interested in safely
> riding down steep grades.
Then shouldn't it help to know as much as possible about what factors
affect blowoff? In addition to the static case, you could ride the bike
with increasingly higher pressures, without braking, to test your
hypothesis that motion between the tire and rim is contributory. If
temperature as well as pressure were a factor, perhaps using a different
material for the tire bead would help.
--
Benjamin Lewis
Luke, I'm yer father, eh. Come over to the dark side, you hoser.
-- Dave Thomas, "Strange Brew"
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