For the contractor that uses a skid steer to clean up his tree jobs, the stump grinder attachment is a no-brainer! It keeps him from having to send out a second crew, it’s more cost effective, and the skid steer can load the chips and level the ground after removing the stump.
What has to be considered is that skid steers cannot produce the hydraulic HP that large diesel stump grinders are able for. There will be some sacrifice in speed in exchange for large time and cost savings using a stump grinder attachment.
Due to the limited flow available (even in a high flow skid steer) there are a few things to watch for. The swing function that some manufacturers offer can be very detrimental to the actual performance of the grinder. Most, if not all, swing functions are hydraulically driven and therefore take away from the hydraulic horsepower available to the motor. Swing functions also normally require electrical connections to operate, giving you more possible service issues and machine compatibility issues.
The most effective stump grinders on the market seem to be the more compact non-swinging types that have a grinding wheel perpendicular to the machine. These types of grinders give the grinding head the full hydraulic flow for maximum torque. Some of these grind while moving the machine forward, some while moving backward and some actually grind in both directions. Being able to grind in both directions obviously increases productivity.
The types of motors available will also play a substantial part in the torque available to the wheel. High speed claims are a trap that some manufactures play on. However, it’s a fact that the higher the speed, the lower the torque. It’s just like a bike… the higher the gear the faster you go, but when you go to climb a hill… no torque. The industry mainly uses geroler/ gerotor type motors which are an average of 70% efficient. This means that only 70% of the oil going to the motor is effective due to “blow by” that is the nature of this type of motor. Others use a piston type motor that can maintain up to a 96% efficiency. One word of caution on piston motors is to look for a reputable brand motor due to the expensive nature of them.
Skid steer stump grinding may not be for every customer. If you have no other reason to have a skid steer on the job or you only do stump grinding (not tree removal) then you would have to weigh your options carefully. It is not a replacement for a 100 HP stump grinder that runs 8 hours a day but, if you take down a tree and grind the stump while still on the job, it might be worth serious consideration. Or, maybe you don’t grind stumps every day and don’t want to spend the big bucks on a big diesel stand-alone unit. Whatever the reason, research carefully, as many lower priced skid steer stump grinders simply don’t cut it… so to speak.
For more advice, contact one of our experts today at 888-376-7027.