Check A Bike’s Bottom Bracket
Introduction
The bottom bracket or crank-axle is the bearing on which the cranks turn.
Pro Tip
It’s useful to disconnect the chain so you can check the resistance in the bottom bracket without interference from the back wheel. It’s easy to do this on derailer bike.
Step 2
Is the bottom bracket loose Enough?
Spin the cranks. They must turn freely with no clicks or catches and minimum friction in the bottom bracket.
Step 3
Is the bottom bracket tight Enough?
Grab a crank and pull it from side to side. If there is discernible movement – play – the bearing in the bottom bracket is too loose.