Use the largest size gear(low gears) at the rear you are comfortable with to keep the legs/ riders cadence high and spinning, as the cadence/rpm rate slows bogging down comes in to affect. Also lower gears/ high rpm cadence will stress the knee joints less. grinding away in gears to high and slow is not the way to ride, your knee joints will suffer over time.
If need be combine using a smaller front gear as well, don't expect to climb hills at 25km/h as one might on level terrain unless you are pro cyclist.
If need be combine using a smaller front gear as well, don't expect to climb hills at 25km/h as one might on level terrain unless you are pro cyclist.