Usefulness of high-pressure/high-volume switch on a track pump Among the track pumps (floor pumps) on the market, I see one advertised with the following feature:


  foot-activated high-pressure/high-volume switch


I'm interpreting this to mean that the pump has two modes:


High pressure and low volume, suitable for pressures between 80psi and 160psi.
High volume and low pressure, suitable for pressures between atmospheric and 80psi.


Is this interpretation about right, and does this feature make it more attractive than other models for someone who'll use it mainly for road bike tires, but also occasionally for mountain bike tires?

I'm intrigued by how they achieve this, since a first guess of how to build it would involve changing the diameter of the tubular air compartment, not exactly something that can be obtained by a switch. But that's for another question (perhaps on some mechanical site).
Are you riding on Tubeless tyres?  If so, the high-volume pump can help to "seat" a tyre to the rim.  

Some tubeless-focused track pumps have a reservoir which can be charged with air, and then released in one fast PHSSSSST to "pop" the bead out to the rim and establish a seal.



Note they should not be stored charged, so its not like a portable air tank or a CO2 cannister.

I've never personally seen a track pump with a switch like you describe, but guessing its trying to be more things for more people.   A conventional floor pump will probably work fine for your bike maintenance needs.   Get an entry-level track/floor pump and go from there.