On anything other than a rental bike, changing gears is an absolute necessity for any track cyclist. The hassle of holding the back-side of your chain ring bolts…is not. Knurling is the small ribbed portion on the back side of the chain ring bolt that holds it in place on your crank. You’ll want to remember that word because it’ll save you a ton of time and a lot of headache. Shimano’s chain ring bolts may be a little more expensive but the knurling they have make them absolutely worth it!