Here's an article Motorcycle Rearsets ? The benefits and how they help you
The benefits of motorcycle rearsets
Creating a stable base – The number one reason why they should be considered is the ability to adjust your foot and therefore leg position to allow you to create a more stable base for your whole body when sitting on and hanging off your bike.
A more stable base means you are using your feet and legs to clamp yourself onto the bike and are less inclined to hang on with your arms, meaning greater freedom for the front end to do it’s job properly, rather than having to deal with your inputs on the bars at the same time (see below for how to set them up properly).
Getting comfortable – As a direct result of the above, a more stable base means less strain on your body to keep you held on the bike, meaning greater comfort and less energy spent during your riding time.
Increased ground clearance – They create more ground clearance and as such allow you to lean the bike more. While this is a good justification for rearsets, the main purpose should be getting yourself stable and comfortable on the bike.
Better grip from pegs – The aftermarket pegs that come with rearsets are often designed to give greater grip than standard road pegs, further improving your lower body’s hold on the bike.