[joshmv]

Hey guys,

I have a Topeak Mountain pump but I just got my first road bike today so I'm trying to decide if I need a second pump.

The gauge only goes up to 75 or 85, so I'm wondering if the pump will still work for higher pressures. I am planning to get a dedicated gauge if so rather than having another pump sitting around.

Has anybody tried this? Sorry if it's a silly question.

Thanks!

 

[looigi]

The force required to compress a pump is determined by the diameter(area) of the piston and the pressure. Bigger pistons require higher force for a given pressure. Pumps for mtb tires have bigger piston diameters to pump more volume which is good for filling the relatively large volume of mtb tires. Road tires have much less volume and run higher pressures, so road pumps usually have smaller diameter pistons which make it easier/possible to reach the higher pressures of road tires.