8mm sterling silver bike chain bracelet size chart:

Below is the correct way to measure your size for a sterling silver bike chain bracelet. 
Cycolinks Sterling Silver Bike Chain Bracelet Size Chart

We recommend that you wear a bracelet 0.5cm - 1cm bigger than your wrist measurement. 

1. A bracelet is perfectly sized when you measure your wrist tightly and add ~0.5-1.5cm.

2. If you are between sizes, ask yourself how you like to wear your bracelet. If you wear it tightly choose the smaller size and if you like to wear it loosely take the next size up.

3. The most popular bracelet size is 19-20cm for men.