With a Penny Farthing, the wheel size is the gear size. Wheel diameter of a typical Penny Farthing might be 52in. This is certainly not a huge gear.
Today, when we talk about "gear inches", let's say 52in, what we mean is that the combination of a certain chain-ring, cog and wheel/tire is equivalent to a wheel of that size (52in) where the cranks are directly connected to the wheel.
Let's say we have a Penny Farthing with a 52in wheel. How does that compare to a modern bicycle?
Let's use 27in as the wheel diameter of our modern bicycle. 52in divided by 27in gives us the gear ratio necessary for an equivalent 52in gear, in this case 1.9. So with a 39t chain-ring we would need (39/1.9) a 20t cog. Also, cruiser bikes will often have a gear just about this size.
com 39/20 consegue-se subir praticamente tudo.
