DRIVING IMPRESSION: Kuhn has revised many details on its GA13231 four-rotor rake. Arguably, the standout change is that the electronics now allow section control of the four rotors.

The hydraulic drive system on Kuhn’s four-rotor rake is seen as one of its main selling points — and this hasn’t changed on the latest generation. Instead, improvements to smaller details are the key focus on the facelifted GA13231 and GA15321 units, which have maximum working widths of up to 12.50m and 14.70m.

Vulnerabilities addressed
In the past, the support shaft on the bogies was prone to cracking above the weld. Thanks to larger diameter, thicker walled steel and a different welding technique, the new support shaft is much studier.

There’s also something new on the hydraulic raking height adjustment of the four rotors: two integrated hydraulic cylinders now lock the mechanism in the adjustment unit. They only open when adjusting the working height, which means the rotors do not have to be adjusted independently. You can still separately adjust the height of each rotor if required. The familiar boost feature has been retained.

Just about floating
The two coil springs that used to suspend the front rotors are gone and have been replaced by the lifting rams on the GA13231. This has two advantages: the target pressure can be set from the control box, which, as well as being convenient, allows the software to adjust the set pressure to the target working width. In wetter conditions, you can set the rotors to almost float, helping reduce soil contamination in the forage.

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