Why would people buy a shorter swing arm and wut purpose do they have

 

It is for flat track racing. It brings the back end in, so it will want to slide around easier. It might be hard to imagine but a minus one inch swing arm makes a HUGE difference.

 

Thats crazy thanks for tellin me wut there used for

 

its most likely lighter to.

 

It also helps the quad to "hook up". A shorter swingarm changes the weight transferred to the rear wheels. Just remember, it will also make it wheelie ALOT easier, and you can't steer it with the front tires in the air.