The safety bicycle was a big improvement on the previous penny-farthing design which it replaced. The chain drive, coupling a large front sprocket (the chainring) to a small rear sprocket (the sprocket) to multiply the revolutions of the pedals, allowed for much smaller wheels, and replaced the need for the large, directly pedaled front wheel of the penny-farthing. The smaller wheel gave a harsher ride; once pneumatic tyres were developed and replaced the previously used solid ones, this disadvantage was no longer an issue.