Shimano SLX M660 Chainrings
For riders looking for the best shifting chainrings available, you can't go past Shimano. Being the first brand to bring in ramped and pinned chainrings, the white lab coat guys at Shimano know a thing or two about giving you the fastest shifting drivetrain available.
 
Part of Shimano's  "HyperDrive" concept, the chainrings utilise SG-X technology for super smooth gear changes when combined with a Shimano front derailleur and chain. They are still compatible with other brands of chains and derailleurs, but for the best results use a Shimano HG chain and front deraileur. The outer SLX chainring features an all alloy construction that is machined, rather than stamped. Cheaper stamped chainrings can be wonky and have poor tooth quality, and while machined chainrings are more expensive to produce, they provide a much higher quality product. The SG-X chainrings feature patented spike pins to give smooth and fast gear shifts even under load, and the trick machining not only looks good, but also saves weight too.
 
Note: If you own the SLX M660 crankset, Shimano recommends replacing the chainrings with genuine Shimano products due to the specific width of the mounting points. Other branded chainrings will fit, but the chainline will be different and front shifting will be compromised.
 
The Shimano SLX Outer Chainring Features:

Shimano parts offer unparalleled smooth, quiet drive train performance.