Paul Southworth <
[email protected]> writes:
>>>> Meanwhile, this can be fixed. I carry a spare stem from a latex tubed tubular tire in my patch
>>>> kit. In the event of a stem separation, I remove the failed stem, insert the tubular stem,
>>>> tighten its clamp nut and inflate the tire. I'm on my way.
>>> That works? What prevents the air from leaking out around the base of the inserted stem?
>> Take a look at one of these stems. Latex does not lend itself to molding around a brass stem as
>> butyl tubes do. Therefore, the stem essentially has a mushroom end that is forced through the
>> hole in the tube that is about as large as the threaded stem diameter. A jam nut id then screwed
>> down on a slightly cup-shaped washer to capture the rubber against the mushroomed end of the
>> stem, that coincidentally has concentric grooves in it. The nut uses the same threads as the
>> knurled nut that started this discussion.
>> Do it. It works.
> So do you have a source for the valve stems, or is there a particular latex tube brand you buy
> that has the magic removable valve stem? I have had a few latex tubes before but none like that.
If you have a good bicycle shop nearby that caters to racers who insist on the lowest RR, they will
have old (flat) latex tubes. I have many of them left over from tubular days. I'm sure there are
dead tubulars around from which you can extract valve stems.
Jobst Brandt
[email protected] Palo Alto CA