pumps

I hate to say it, but it sounds like the same problem I had with a Bell pump frame mount pump. It
was junk and I replaced it. It would not dependably pump to 35 psi. I drove to the store, bought a
new one (Blackburn), and tested it in the parking lot before driving home. Any good pump should be
capable of 75 psi, and most will go to 120. In my opinion, any other brand you buy will be better
than a Bell.

Good luck, Ernie

TF said:

Is my pump dead? I have a Bell bicycle tire pump...I am able to inflate my tires to about 35PSI
and then the internal pressure of the tire will start to push the handle back up and makes it very
difficult to inflate more than that. I once got it up to about 38PSI (according to my digital tire
gauge) and then I attached my pump again to try and get it higher. When I attached the valve and
sealed it, the handle shot upwards at my neck like a guillotine trying to choke me
:-/...last time I'm putting my neck over that pump. Even if I can get
the pressure higher, there is a lot of force pushing back up on the handle and if I don't push
back down, the air will leak out of the pump and my tire.

I walked my over to my friend's house half block away and then borrowed his Blackburn pump to
inflate my tires to 65 PSI (the reccomended max for my tires). I never used his pump and it seemed
much much easier to inflate to 65 PSI than I could do with my Bell pump. Even before today, I was
only able to pump my tires to about 50PSI with my Bell pump and it was a struggle to get there in
teh first place. I did notice a difference between his pump and my pump though. The barrel on his
pump was quite a bit narrower and somewhat taller than teh barrel on my Bell pump. His pump was
also significantly heavier than mine. Does the dimmensions and construction of the barrel make a
difference on the force required to pump air?

Is my Bell pump dead or a bad pump? My neighbor was selling a SKS AVACS Ren something or other
pump during his garage sale but no one bought it. This like the Blackburn was skinnier than my
Bell pump. Is that SKS a good one?

TF <[email hidden]> wrote:

: Is my Bell pump dead or a bad pump? My neighbor was selling a SKS AVACS Ren something or other
: pump during his garage sale but no one bought it. This like the Blackburn was skinnier than my
: Bell pump. Is that SKS a good one?

Bell is a pretty ordinary brand. On the other hand, SKS is a great name in pumps. I'd definitely buy
it if it was in working order.

Cheerz, Lynzz

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Is my pump dead? I have a Bell bicycle tire pump...I am able to inflate my tires to about 35PSI
and then the internal pressure of the tire will start to push the handle back up and makes it very
difficult to inflate more than that. I once got it up to about 38PSI (according to my digital tire
gauge) and then I attached my pump again to try and get it higher. When I attached the valve and
sealed it, the handle shot upwards at my neck like a guillotine trying to choke me
:-/...last time I'm putting my neck over that pump. Even if I can get
the pressure higher, there is a lot of force pushing back up on the handle and if I don't push
back down, the air will leak out of the pump and my tire.

Sounds like the check valve in the bottom of the pump gave out; mine did that last fall after many
years of service. Buy a new one.

Quoted message said:

I walked my over to my friend's house half block away and then borrowed his Blackburn pump to
inflate my tires to 65 PSI (the reccomended max for my tires). I never used his pump and it seemed
much much easier to inflate to 65 PSI than I could do with my Bell pump. Even before today, I was
only able to pump my tires to about 50PSI with my Bell pump and it was a struggle to get there in
teh first place. I did notice a difference between his pump and my pump though. The barrel on his
pump was quite a bit narrower and somewhat taller than teh barrel on my Bell pump. His pump was
also significantly heavier than mine. Does the dimmensions and construction of the barrel make a
difference on the force required to pump air?

Absolutely. A smaller barrel means you can generate higher pressures with less force, because the
total area you are trying to move is smaller. For example, if the barrel has an area of 1 square
inch and you are pumping to 50 psi, you have to provide 50lbs of force. A 1/2 square inch area at 50
psi means you only have to provide 25 lbs of force. Of course you aren't moving as much air at a
time, so it will take more strokes of the pump (or longer ones) to fill up the tire.

....

--
David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord,
it's morning".

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