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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
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.
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.
On Sat, 10 May 2025 15:22:38 -0000 (UTC), bp@www.zefox.net wrote:
I do have an old "WindPipe", from Specialized. This is two-mode,Rebuild kit: <https://www.certini.co.uk/accessories/pumps/specialized-windpipe-rebuild-kit--silverblack__45392>
Offhand, it looks like the seals are o-rings. Measure your existing
o-rings and find substitutes. <https://www.harborfreight.com/search?q=o-rings> <https://www.ebay.com/itm/372061728115> <https://www.ebay.com/itm/372621207595>
There might be a leather "cup" valve inside. <https://www.pyramydair.com/blog/2007/12/how-to-make-a-leather-piston-seal/>
If you want an air pump with really high pressure, look into air gun
pumps, which typically operate between 100 and 200 psi but can go much higher. <https://www.airgundepot.com/vault/articles/how-much-psi-can-a-hand-pump-produce/>
4 stages perhaps? <https://www.amazon.com/NDCYJG-Pressure-4500Psi-Filling-Stirrup/dp/B0CGF988MN>
"Today?s hand pumps can hit 4500 psi."
Try a conventional single stage bicycle pump to get to around 100 psi,
and then use a two or more stage air rifle pump to go higher. Trying
to pump to high pressures from atmospheric pressure involves too many
low volume hand pump strokes.
Another problem with high pressure air rifle pumps is heating: <https://en.wikipedia.org/wiki/Boyle%27s_law>
The usual method is to pump a little, wait for the pump to cool down,
and continue. I also suggest that you carefully monitor the air
pressure to prevent your tire and valve stem from achieving escape
velocity.
No warranty expressed or implied on my advice.
On 5/10/2025 10:22 AM, bp@www.zefox.net wrote:
Are there any two-stage tire pumps on the market? I'm lookingSuch exist:
https://giyopumps.com/blog/what-is-a-2-stage-bike-pump/
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.
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 lookingSuch exist:
https://giyopumps.com/blog/what-is-a-2-stage-bike-pump/
If I'm reading right, that's a 2-mode pump, not 2-stage.
The selector gives it away.
A real 2-stage pump has no selector; the first stage delivers
output to the second stage, the second stage delivers output
to the receiver (tire, in this case). No need for a selector.
If the first stage pressure exceeds that of the tire, the air
just passes through the second stage. If the tire pressure is
higher than the first stage delivers, the air pauses in the
second stage to be compressed again on the return stroke.
Thanks for writing,
bob prohaska
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
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
Just saw this while looking for something else:
https://www.topeak.com/global/en/product/1142-ROADIE%20DA%20G
Just saw this while looking for something else:
https://www.topeak.com/global/en/product/1142-ROADIE%20DA%20G
