New Pump- Size Query



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Gadget

Guest
I would like to purchase a Zefal HPX but all the sites say the 4 sizes has to be measured "center to
top". Now I've heard this phrase batted around a bit but am a little confused as to what this means.
If I remember my cycle mechanics right, am I looking to measure the seat post?

Gadget
 
P

Pete Biggs

Guest
Gadget wrote:
> I would like to purchase a Zefal HPX but all the sites say the 4 sizes has to be measured "center
> to top". Now I've heard this phrase batted around a bit but am a little confused as to what this
> means. If I remember my cycle mechanics right, am I looking to measure the seat post?

No, they're refering to the frame's seat tube - that's the near-vertical bit of the frame that
goes from the cranks to the seatpost. "Centre to top" means from the centre of the bottom bracket
to the top of the seat tube. Measure from the middle of the bolt in the middle of the chainset
(that'll do).

BUT, this is only strictly relevant if you're going to fit the pump on the seat tube. You don't have
to (and won't want to if you'e got two bottle cages). It can go under the top tube (crossbar) by
using a peg/clip/strap, etc. (Ask if you need further advice on that).

~PB
 
T

Tony R

Guest
"Pete Biggs" <pLime{remove_fruit}@biggs.tc> wrote in message
news:[email protected]...
> Gadget wrote:
> > I would like to purchase a Zefal HPX but all the sites say the 4 sizes has to be measured
> > "center to top". Now I've heard this phrase batted around a bit but am a little confused as to
> > what this means. If I remember my cycle mechanics right, am I looking to measure the seat post?
>
> No, they're refering to the frame's seat tube - that's the near-vertical bit of the frame that
> goes from the cranks to the seatpost. "Centre to top" means from the centre of the bottom bracket
> to the top of the seat tube. Measure from the middle of the bolt in the middle of the chainset
> (that'll do).
>
> BUT, this is only strictly relevant if you're going to fit the pump on the seat tube. You don't
> have to (and won't want to if you'e got two bottle cages). It can go under the top tube (crossbar)
> by using a peg/clip/strap, etc. (Ask if you need further advice on that).
>
> ~PB
>
I was thinking about an HPX to go under the top tube. Are they really secure though? My frame has a
wee peg thingy on the head tube - I presume a slight amount of compression of the pump keps it snug
against the seat tube. Are they likely to bounce out during unwise pothole negotiation? Tony R.
 
P

Pete Biggs

Guest
tony R wrote:
> I was thinking about an HPX to go under the top tube. Are they really secure though? Are they
> likely to bounce out during unwise pothole negotiation?

Can be very secure indeed, depending on exactly how it's done. I used well-fitting metal clip-on
pegs with previous bike, and am now using the head of a cable tie around the head tube as a peg.
I've hit potholes that were bad enough to sprain wrists and launch me over the bars - and been hit
side-on by a vehicle launching me and the bike to the other side of the road - all without
dislodging the pump.

> My frame has a wee peg thingy on the head tube - I presume a slight amount of compression of the
> pump keps it snug against the seat tube.

Yes but it depends on shape of peg and amount of compression. Does need a certain good amount of
compression, so depends on how lucky you are with tube/pump length.

Try it, then if it doesn't seem very secure, a velcro strap (or even two) around top tube will hold
it. If that's too much hassle though, then I would even consider sawing/filing off the peg (assuming
it's a braze-on one) and either using a metal clip-on peg on the top tube or a cable tie as
described above instead.

I've found plastic clip-on pegs on top tube can't be tightened sufficiently to resist the pump's
compression when peg needs to be fitted away from the end of the tube (ie. when pump isn't long
enough to go all the way to the end). These pegs can gradually slide back making the pump insecure.

Small tip: A foam pad stuck with double-sided tape under the top tube can stop the handle rattling.

~PB
 
A

Andrew Sweetman

Guest
tony R <[email protected]> wrote ...
> "Pete Biggs" <pLime{remove_fruit}@biggs.tc> wrote in message
> > BUT, this is only strictly relevant if you're going to fit the pump on
the
> > seat tube. You don't have to (and won't want to if you'e got two bottle cages). It can go under
> > the top tube (crossbar) by using a peg/clip/strap, etc. (Ask if you need further advice on
> > that).
> >
> I was thinking about an HPX to go under the top tube. Are they really
secure
> though? My frame has a wee peg thingy on the head tube - I presume a
slight
> amount of compression of the pump keps it snug against the seat tube. Are they likely to bounce
> out during unwise pothole negotiation? Tony R.
>

The spring in the pump handle is there solely to keep the pump in the frame. Security will depend on
how slight the amount of compression is. The top tube will presumable need slightly more grip than
down the seat tube, which may mean that there are some frame sizes that fall between the available
pump sizes. I have used an HPX4 under the top tube of a 57.5cm frame with a similar peg on the head
tube. This was a fairly tight fit, and I had no problems with security. However I did find that it
rattled a bit (inside of handle against outside of barrel), so I started using a velcro strap, which
would also be a solution if your pump doesn't fit as snugly as mine. I got my last strap from the
CTC shop - a Zefal "Doodad".

Andrew
 
P

Pete Biggs

Guest
> velcro strap, which would also be a solution if your pump doesn't fit as snugly as mine. I got my
> last strap from the CTC shop - a Zefal "Doodad".

One can also be made from any velcro strips that can be bought from a department store, etc. Just
need a fluffy length with a short bit of hooky stuff superglued on the reverse at the end, or
vice versa.

~PB
 
S

Steve Palincsar

Guest
On Sat, 29 Mar 2003 06:34:52 -0500, Pete Biggs wrote:

> Small tip: A foam pad stuck with double-sided tape under the top tube can stop the handle
> rattling.

So will a few wraps of friction tape around the handle of the pump.
 
T

Tim Hall

Guest
On Sat, 29 Mar 2003 11:34:52 -0000, "Pete Biggs" <pLime{remove_fruit}@biggs.tc> wrote:

<HPx>
>
>Small tip: A foam pad stuck with double-sided tape under the top tube can stop the handle rattling.
>

Ah! Thank you, thank you. Silence will return once more.

Tim
--

fast and gripping, non pompous, glossy and credible.
 
T

Tony R

Guest
"Pete Biggs" <pLime{remove_fruit}@biggs.tc> wrote in message
news:[email protected]...
> > velcro strap, which would also be a solution if your pump doesn't fit as snugly as mine. I got
> > my last strap from the CTC shop - a Zefal "Doodad".
>
> One can also be made from any velcro strips that can be bought from a department store, etc. Just
> need a fluffy length with a short bit of hooky stuff superglued on the reverse at the end, or
> vice versa.
>
> ~PB
>
Thanks for the tips. I like a nice quiet bike so they're much appreciated. Tony R.
 
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