Flow Fitness NOW TM2.5 Treadmill – UK Special Edition The UK Special Edition Flow Fitness TM2.5 Treadmill comes with a blistering maximum speed of 20km/h, but what puts it into a different league from other treadmills in its price range is that it comes with a max user weight 150KG and the state-of-the-art Xsorb suspension system. Top speed of 21km/h (13.0 mph). Maximum incline level of 15%.