Shock Pump question

[Heel Drop]

So I got a shock pump today and I am wondering......

 

the pump inlet screws onto the valve and then a second knob must be turned to open the valve and let the air in.( Its liek a little secondary turning knob that has a pin that opens the valve)

 

I pump it see the pressure but then when I undo the knob to stop the air from going in/coming out I hear a little air escape.

 

Because the air pressure is so high I wonder if when I read the pressure this air that escapes contirbutes to that reading and that means when I undo the knob and I hear air going out the actual reading is then less.

 

When I use the air outlet knob its so sensative you just touch it and the PSI drops by 10-20 psi . I am just wondering when I read is it really that accurate once I undo the pump .If a little air escapes the reading drops

 

 

Any case that is what logic tells me.

[Trance Dance]

Do a test: pump it to desired pressure, unscrew the pump. Re-attach the pump and see what it reads. It should be the same. If not, then air does escape.

[MrJacques]

That little bit of air escaping is normal, I think, and it shouldn't make a big difference. You can always check the sag of the fork with the pump attached and after you have removed it.

[King_Crispy]

Do a test: pump it to desired pressure, unscrew the pump. Re-attach the pump and see what it reads. It should be the same. If not, then air does escape.

+1

Applied logic

 

 

Seriously. You're new to this. It's something you have to practice. Getting it in and out on and off. You will figure it out quick enough.

You keep pressing down on the nipple while unscrewing it. It's something that you fiddle with a few times then, BAM, s h i t, it works!

[Frosty]

It's the air from the pipe between the pump's piston and the valve stem.

Unscrew that "secondary" knob first before unscrewing the one on the valve - and the only air to escape is the air in the pipe.

Edited September 15, 2012 by geraldm24

[Heel Drop]

jip very new to this ...............but thanks got it

[awesme]

hmm

 

It might actually be a little down, as air comes out of the form and into the pipe between the form and pump to then drive the pressure gauge.

 

When pumping all you're looking for is the pressure in the fork, once you get to the desire pressure disconnecting the pump causes the valve on the fork to seal, keeping that pressure inside the fork, as you disconnect the pump the air in the rubber line escapes, when you now reconnect the line you will get air from the form filing the line, thus decreasing the fork the slightest amount.

 

G

 

Do a test: pump it to desired pressure, unscrew the pump. Re-attach the pump and see what it reads. It should be the same. If not, then air does escape.

[kosmonooit]

A P A P O P

[Frosty]

A P A P O P

That are the Afrikaans version

 

The soutie version would be... A P I A P O P

[awesme]

huh

 

and now in all understandable no acronym words ?

 

on the subject of shock pumps, any good experience, models that can be suggested?

 

G

[kosmonooit]

huh

 

Sorry it's an East Rand joke. You have to have been there ... although I can't reallly look back to that period with fond nostalgia.

 

I have a Lezyne Shock Pump, very well make and portable, You get larger one with a dial.

 

http://www.bicycleexpress.com.au/site/DefaultSite/filesystem/images/Store/Products/Accessories/LezyneShockDrive.jpg

Edited September 18, 2012 by kosmonooit

[scotty]

Not sure what make mine is i was given it by my LBS, it has a little rubber knob you press after pumping which releases the air trapped in the pipe, tested it by re attaching and checking the pressure and it's correct.

[akneethling]

I've got one of these........ Works for me. Paid R80 for it.

 

http://www.topeak.com/products/Pumps/Pressure-Rite