In the bearings
The brakes use friction to stop the bike and the tyres use friction to grip the road.
friction
Probably from the friction of the air squeezing through the small space?
Friction is what ultimately stops your bike
Friction. Air friction, road friction and mechanical friction.
friction
Fluid Friction, & Rolling Friction.
The friction is useful on a bike when you push it.
it gets hot
Friction Is Useful For Lots Of Things Like Walking Or Riding a Bike
Sliding Friction
friction