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Gear Box versus Direct Drive Brush Cutters 

84 brush Cutter feature

Should a brush cutter have a gear box or a direct drive? When skid steer brush cutters first hit the market, they were based primarily on a tractor bush hog design with a right-angle gear box, shear pins and a clutch plate. This design was full of both unnecessary features and weak points.

Users quickly found that being able to raise and lower the cutter meant that larger material could be tackled. In addition, the fact that skid steers could get where tractors couldn’t, meant new areas were being cut that had been left before. Cutting these new areas meant finding hidden obstacles like rocks and stumps.

Soon gear box shafts were being broken rapidly despite trying to use stump jumpers. Also manufactures were beginning to experiment with going beyond the traditional 2-blade design and going to a 3- or 4-blade design. This new trend of extra blades greatly increased the cut quality and productivity but again, gear box failures were the weak point.

gear box or direct drive on skid steer brush cutter

Blue Diamond Direct Drive

Blue Diamond spent extensive time trying to find a gear box to handle this new design and decided that if we were going to have a durable drive system, we would have to build it ourselves.

Are all direct drives equal? Absolutely not. Many direct drives are barely an improvement on a gear box. They still use a 1” to 1.5” shaft with a single nut holding it on to the splined shaft. In this case, they still require a stump jumper to keep from breaking the shaft off.

When we made our brush cutters, we made a custom direct drive. Our direct drive features:

  • A 3.5” forged shaft with a 0% breakage rate
  • Blade carrier connects to the shaft with 10 ¾” hardened bolts (no need for a stump jumper)
  • Grease filled drive eliminates oil loss due to barbed wire cutting lower seal
  • Motor splines directly into shaft eliminating and shear pins and or clutches


Blue Diamond Attachments uses this brutal drive system in every brush cutter we make. Could we use a lighter drive in our less expensive models? Yes, but we aren’t going to because we want your experience to be the best we can make it. Paying less up front will most likely give you more down time, more parts expense and a worn-out brush cutter long before it should be.