Rutting isn't just about machine weight, tire width will also factor into it. The lightest Rider type mowers are likely the 28"-30" snapper or Cub Cadet rear engine riders. With those machines the majority of the weight is on the rear wheels. A 42" front engine Rider will have a wider rear tire, wider front tires and better weight distribution despite it being heavier. Commercial machines typically weigh hundreds of lbs more than consumer machines.