Re: Two stage tire pump?

On Sat, 10 May 2025 10:35:47 -0500, AMuzi <am@yellowjersey.org> wrote:

On 5/10/2025 10:22 AM, bp@www.zefox.net wrote:

Are there any two-stage tire pumps on the market? I'm looking
for a frame-sized pump that makes it a little easier to get
near 100 psi. Best I know of is the Topeak Road Morph, but it's
single stage and takes most of my weight to surpass 100 psi. Not
impossible, but sure to get harder with time.
 
A pump that perhaps doubles or triples pressure on the pull stroke
and then delivers output on the push would help a great deal.
 
I do have an old "WindPipe", from Specialized. This is two-mode,
not two-stage. It uses a very small-bore cylinder for high pressures
and a co-axial large-bore cylinder for low pressure. The internal seals
gave up and it no longer develops any pressure at all. Far as I can
tell they're no longer offered. It was helpful while it worked, but
being single-stage the volumetric efficiency was always lousy.
 
Thanks for reading,
 
bob prohaska
 

>
Such exist:
>
https://giyopumps.com/blog/what-is-a-2-stage-bike-pump/
>
and have for quite some time:
https://www.yellowjersey.org/photosfromthepast/n_1pmp_ho.jpg
>
and you are correct in principle. That said, as you noted,
quality, longevity, efficiency and price can be significant
factors besides the basic design itself.
>
n.b. first link above is not an endorsement.

I usually pump my tires to 80 PSI. I carry a Topeak Road Morph on the
bike for use out on a ride, but I'm content with only having 40/50 PSI
in a tire while finishing a ride. I carry a Topeak Joe Blow in the
truck.

--
C'est bon
Soloman