Changing to a lower gear makes it easier to pedal uphill. You single speed is quite simply a lower gear than your fixed gear.
Either match the teeth on chainring and sprocket/freewheel on both bikes or just divide the number of teeth on the chainring by the number of teeth of sprocket/freewheel and make sure you get a number which is the same as the one you like.
Have you ever ridden a geared bike?
Changing to a lower gear makes it easier to pedal uphill. You single speed is quite simply a lower gear than your fixed gear.
Either match the teeth on chainring and sprocket/freewheel on both bikes or just divide the number of teeth on the chainring by the number of teeth of sprocket/freewheel and make sure you get a number which is the same as the one you like.