Why is it so much harder to keep up speed on your bike when you’re in the grass than when you’re on dirt or hard soil?

Question

It feels like the tiny little speck of grass shouldnt bring that much friction. Is there something I’m missing?

In: 2

Answer 1

Simplest answer?
FRICTION.

Pavement is smooth, it has very little ‘drag’ on your bike tires, allowing them to rotate easily.

When you try to pedal through grass, the grass itself, and the soil it’s rooted in create ‘drag’ on your tires, impeding your ability to pedal easily.

Think of it as little ‘bike brakes’. You know how when you engage the brakes on your bike, those little rubber pads ‘grab the tire rims’ and slow/stop you? Well, picture the grass doing the same thing, hundreds of times, but very, very weakly, as the grass flexes when you roll thru it. The soil does a similar thing. But, bottom line, is FRICTION.