You should choose your bike pump based on 2 criteria: your use (quickly inflating the tires after a ride or fixing it at the side of the road) and the type of bike you are pumping up.
What do you need a bike pump for? For inflating a tire, of course! True, but not everyone has the same needs. You might just be re-inflating tires after a ride, or you may be dealing with an urgent repair miles away from home.
Quickly Inflating Your Tyre After a Ride:
Go for a foot pump or compact foot pump model to make pumping up your tires quicker and more comfortable (you will push more air into the tire each time than with a hand pump). Generally, foot pumps will pump to a higher pressure than hand pumps. They also require less effort to use.
A foot pump will be more precise: this kind of bike pump generally comes with a pressure gauge so that you can see the tire's pressure
Repairing Your Bike During a Ride:
If you need to carry your pump with you on bike rides, go for a hand pump or CO2 cartridge.
These small, compact solutions are easy to carry in a bag, on your bike's frame or in the pocket of your cycling jersey.
In terms of precision, some hand pumps have a pressure gauge for accurately inflating your tires.
CO2 cartridges are effective and very fast, but can only be used once.
2. The Type of Bike You are Pumping
Don't leave anything to chance: mountain bike and road bike tires have very different pump requirements. For other bike models (city bikes and hybrid bikes), the choice of pump won't be so strict.
Mountain Bike Tire:
For your mountain bike, go for a pump with a wide body so that you push a large amount of air in each time. This will inflate your tire more quickly.
Go for a pump with a thin body that, even though it pumps less air each time, will let you get up to at least 7 bars - the pressure you need for road cycling.
Certain pumps also have a telescopic function for pumping even more air when you first start pumping.