ping123

I am considering to buy an electric pump. A standard size hand pump comes with a lever to lock and unlock the pump head from the tyre valve. This lever also pushes down the pin of a schrader valve. The lever mechanism may act as a quick release when the tyre is fully inflated. That keeps the air leakage to minimum when we unlock the pump head.

Many electric pumps do not have lock levers. The pump head and the inner tube value are connected by turning action which is slow. Will significant amount of air leak out when we unscrew the pump head and cause a pressure drop of more than 10 psi? I usually pump the tyres to about 100 psi.

Moe Zhoost

Replace the chuck with one with a quick release mechanism. I use the JACO Lightning S2 chucks.

ping123

I bought a Xiaomi 1S Electric Air Pump. Very good product overall. No leakage of air when unscrewing the pump head off.

Troul 

I was hoping that it was a slip fit for a presta valve.

79pmooney

OP, be aware that any pump with a hose will lose air when you remove the chuck. But that does not mean the tire lost any. The presta valve is held shut by air pressure inside the tire and only releases air when it is pushed in. A proper chuck, whether slip-on, slip-on with lock or screw-on does not push that valve in when you remove it. The air you hear being lost is the compressed air inside the hose. (It is possible to be clumsy and push that valve in with many chucks. The old advice was to "karate chop" your pump head to knock it directly down the direction of the valve stem. Not so feasible with all chucks but you get the idea.)