Weird jerking at takeoff…

So my wifes 2011 Polaris 550 is acting up. Didn’t really notice anything while riding on the dirt trails, but once we got on gravel or pavement we really noticed it.
When at a dead stop and you start accelerating, the wheeler jerks until it gets moving/rolling. Once your moving it doesn’t happen anymore until you come to a stop and then start going again. It seems more noticeable going forward vs. reverse.

If you watch the first video below and watch the back tire really close you will see it slip as i start going forward.

My initial thought was a flat spot on the belt, however when i took the belt off and measured it with a calipers i only found a .010" variation in 1 spot and it wasn’t glazed or anything. The wheeler only has a couple hundred miles on it and i’d like to be certain it’s the belt before i drop $100+ on a new belt.

Any ideas??

Weird jerking at takeoff…

So my wifes 2011 Polaris 550 is acting up. Didn’t really notice anything while riding on the dirt trails, but once we got on gravel or pavement we really noticed it.
When at a dead stop and you start accelerating, the wheeler jerks until it gets moving/rolling. Once your moving it doesn’t happen anymore until you come to a stop and then start going again. It seems more noticeable going forward vs. reverse.

If you watch the first video below and watch the back tire really close you will see it slip as i start going forward.

My initial thought was a flat spot on the belt, however when i took the belt off and measured it with a calipers i only found a .010" variation in 1 spot and it wasn’t glazed or anything. The wheeler only has a couple hundred miles on it and i’d like to be certain it’s the belt before i drop $100+ on a new belt.

Any ideas??