Nouns ending in -ette are usually feminine.
The suffix often forms a diminutive.
Is bicyclette masculine or feminine?
labicyclette
The rule behind it
99.3% of -ette nouns are feminine
In context
Je vous donnerai une bicyclette pour votre anniversaire.
I will give you a bicycle for your birthday.
Tu ne sais pas faire de la bicyclette ?
Can't you ride a bicycle?
Ne laissez pas la bicyclette sous la pluie.
Don't leave the bicycle out in the rain.