Pump gauge always reads low
 

So I was pumping up my Specialized Armadillo 700x25 to the recommended pressure of 115-125psi. I accidentally pumped one tire to 130, so I unhooked the hose of my Blackburn Air Tower floor pump. A few minutes later I tried it again but the guage read 40psi. The tire felt pretty solid and I doubt that much air could have leaked in a few minutes.

How am I supposed to use the gauge? Every time I start the gauge reads pretty low. I don't want to burst an inner tube by over-pumping it.


By the way, they're schrader valves. I don't know if that makes a difference.

get a 2nd opinion Gage, GH Meiser, of Posen Ill, 60469 made the Accugage,
its a lifetime + quality Gage.

Made in Presta or Schrader .. dial up to 160 psi

so it's not normal for the gauge to read differently each time I attach the nozzle to to the valve?

May be a problem specific to your pump. have you spoken to the dealer or contacted manufacturer?
to outline the differences,
After opening the nut and tapping the stem to unstick the valve,
Presta valves open with the air pressure from the pump being greater than the
air pressure in the tire-tube. they are the most common type valve for high pressure
bike tires

Schrader valve cores have a spring in them, and the pump head needs a pin to keep the pin in the valve core open.,
more common on low pressure mountain and junior bike wheels,

Perhaps your initial reading is the pressure in the hose and not reading the tire?

though I have a tire gage off the pump, the 2 pumps i have:
from Medai, and Silca, have been pretty reliable.

Just a long ways down to the floor, and my eyesight is not as good ,
My now being over 60.

The guage is ok. After you attach the hose to the valve, you have to pump it until the air just starts to go into the tire, thats your tire pressure.

thank you. I'm still going to take the pump and the bike back to the LBS and ask them if I'm using it right.