This is the Focus Applied Technologies Baby Chassis Dynamometer for motorcycles.
The wheel of the vehicle undertest sits here in between these two rollers.
The front roller is the idler roller preventing the the vehicle from running away,
While the back roller, the driven roller transmiting torque through this belt to the dynamometer.
It is suspended on the bearings before and aft and torque is measured from this load cell.
Speed is measured from the speed pick up on the main roller,
Both torque an speed are reported to the dynamometer controller which is also responsible of controlling the load.