screw threads on inner tubes - mismatch

[Julian Gallop[_3_]]

I am running into a problem with screw threads on inner tubes.

Until recently, I thought that valves were straightforward. There were
just 2 types if you ignore Woods. So by making sure that I specify the
right valve, I never had trouble buying a new pump connector or a new
inner tube at different times. Screwing on the pump connector to the
valve just worked. So previously screw threads for Schrader valves were
compatible or else I have been lucky. Sheldon Brown at
http://www.sheldonbrown.com/gloss_sa-o.html mentions just one thread 7.7
mm (.302") x 32 T.P.I.

However two weeks ago, I bought a new inner tube over the web, making
sure it was the right valve type (Schrader). However when I tried to
attach the pump connector, there is some mismatch. I either fail to
attach it completely or succeed eventually in attaching but fail to
detach it quickly enough before all the air rushes out. As you can
imagine, this is extremely frustrating.

So for Schrader valves, what possible screw threads are there out there?
And how does one specify the screw thread when buying over the web?
(I would use the local bike shop if it hadn't shut recently - this is
the sort of thing they would have known).

Thanks in advance,

Julian Gallop


Thanks in advance,

Julian Gallop

[Rob Morley]

In article >, Julian Gallop
says...
<snip>
> So for Schrader valves, what possible screw threads are there out there?

Just the one - the problem may be caused by wide manufacturing
tolerances.

[Pete Biggs]

Julian Gallop wrote:
> I am running into a problem with screw threads on inner tubes.
>
> Until recently, I thought that valves were straightforward. There
> were just 2 types if you ignore Woods. So by making sure that I
> specify the right valve, I never had trouble buying a new pump
> connector or a new inner tube at different times. Screwing on the
> pump connector to the valve just worked. So previously screw threads
> for Schrader valves were compatible or else I have been lucky. Sheldon
> Brown at http://www.sheldonbrown.com/gloss_sa-o.html mentions
> just one thread 7.7 mm (.302") x 32 T.P.I.
>
> However two weeks ago, I bought a new inner tube over the web, making
> sure it was the right valve type (Schrader). However when I tried to
> attach the pump connector, there is some mismatch. I either fail to
> attach it completely or succeed eventually in attaching but fail to
> detach it quickly enough before all the air rushes out. As you can
> imagine, this is extremely frustrating.
>
> So for Schrader valves, what possible screw threads are there out
> there? And how does one specify the screw thread when buying over
> the web? (I would use the local bike shop if it hadn't shut recently
> - this is the sort of thing they would have known).

You'll be better off with a pump connector that just pushes onto the valve
rather than screwing on. It'll be compatible with all your valves, and, if
it's a good one, won't leak.

~PB

[7@m3 G33k]

Pete Biggs wrote:
<snip>
> You'll be better off with a pump connector that just pushes onto the valve
> rather than screwing on. It'll be compatible with all your valves, and, if
> it's a good one, won't leak.
>
> ~PB
>
>

I'll go along with that. Any decent pump these days will have a
reversible washer & insert combination to allow you to use the pump with
both Schrader and Presta valves. To be honest I've not seen a pump with
a screw-in adapter like that for years and a good job too: they were
always a right pain in the backside to use!

So treat yourself a nice new pump. I've always found Topeak to be
effective and made to last. And once you've got a sparkly new pump start
switching to Presta valve innertubes: much easier to inflate than
Schrader IMHO.

Ian

[[email protected]]

On 8 Sep, 10:42, "Pete Biggs"
<p...@pomegranateremovehighlyimpracticalfruitbiggs. tc> wrote:
> Julian Gallop wrote:
> > I am running into a problem with screw threads on inner tubes.
>
> > Until recently, I thought that valves were straightforward. There
> > were just 2 types if you ignore Woods. So by making sure that I
> > specify the right valve, I never had trouble buying a new pump
> > connector or a new inner tube at different times. Screwing on the
> > pump connector to the valve just worked. So previously screw threads
> > for Schrader valves were compatible or else I have been lucky. Sheldon
> > Brown athttp://www.sheldonbrown.com/gloss_sa-o.htmlmentions
> > just one thread 7.7 mm (.302") x 32 T.P.I.
>
> > However two weeks ago, I bought a new inner tube over the web, making
> > sure it was the right valve type (Schrader). However when I tried to
> > attach the pump connector, there is some mismatch. I either fail to
> > attach it completely or succeed eventually in attaching but fail to
> > detach it quickly enough before all the air rushes out. As you can
> > imagine, this is extremely frustrating.
>
> > So for Schrader valves, what possible screw threads are there out
> > there? And how does one specify the screw thread when buying over
> > the web? (I would use the local bike shop if it hadn't shut recently
> > - this is the sort of thing they would have known).
>
> You'll be better off with a pump connector that just pushes onto the valve
> rather than screwing on. It'll be compatible with all your valves, and, if
> it's a good one, won't leak.
>
> ~PB

Thanks for the replies on this thread about threads. Yes I now have
a pump that pushes onto the valve. It has a lever action to establish
connection with the vital part of the valve. As you say, it doesn't
critically depend on the screw thread. Problem solved.

Julian Gallop

[reason for delay in acknowledging - I did a lot of travelling for
work and had less good Internet connections than anticipated. Replies
were appreciated]