Tom Keats
December 30th 05, 03:41 AM
In article >,
Steve Sr. > writes:
> I was wondering if anyone has any information on the porosity of
> various kinds / brands of innertubes. By porosity I mean the very slow
> leakdown rate that occurs with sound tubes over days and weeks. You
> know... The reason you are always topping up your tires to prevent
> pinch flats.
>
> My current interest is any differences between the regular and
> "lightweight" road tubes of the same size. I am also wondering if
> "brand" makes any difference as well.
Y'know, I've had tubes of the same brand with different seepage rates.
So IMO, the particular brand may not be a useful quantifier.
There may be a variation from batch to batch with tubes from
the same manufacturer (or factory.) There may even be a variation
within batches.
I believe getting an especially air-retaining or an especially
air-losing tube boils down to the luck of the draw.
In general, tubes made from natural latex are lighter than butyl
tubes, and are somewhat more porous . Perhaps the weather
conditions at the rubber plantations might cause some variation
in the quality of batches of latex tubes? I dunno -- maybe how
closely latex or butyl tubes are stored to the ship's generators
(or other cargo whose out-gassings might react with "rubber")
en route from China might affect their quality too.
cheers,
Tom
http://www.sheldonbrown.com/tires.html
--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca
Steve Sr. > writes:
> I was wondering if anyone has any information on the porosity of
> various kinds / brands of innertubes. By porosity I mean the very slow
> leakdown rate that occurs with sound tubes over days and weeks. You
> know... The reason you are always topping up your tires to prevent
> pinch flats.
>
> My current interest is any differences between the regular and
> "lightweight" road tubes of the same size. I am also wondering if
> "brand" makes any difference as well.
Y'know, I've had tubes of the same brand with different seepage rates.
So IMO, the particular brand may not be a useful quantifier.
There may be a variation from batch to batch with tubes from
the same manufacturer (or factory.) There may even be a variation
within batches.
I believe getting an especially air-retaining or an especially
air-losing tube boils down to the luck of the draw.
In general, tubes made from natural latex are lighter than butyl
tubes, and are somewhat more porous . Perhaps the weather
conditions at the rubber plantations might cause some variation
in the quality of batches of latex tubes? I dunno -- maybe how
closely latex or butyl tubes are stored to the ship's generators
(or other cargo whose out-gassings might react with "rubber")
en route from China might affect their quality too.
cheers,
Tom
http://www.sheldonbrown.com/tires.html
--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca