This is a small Lego Technic tractor I’ve designed, based on the new 56mm Lego tractor tires and Lego Power Functions. It uses two PF Medium motors for driving and steering. Because it is a small model the IR receiver and batterybox don’t fit in the tractor, it needs the trailer or the 2-point batterybox-attachment. Especcialy the trailer adds to the playability of the set.
Get the instructions and partslist of this moc on Rebrickable.
As shown in the pictures the trailer can handle the 5x7x3 cargo crates which add to the playability. The crates are not included in the moc so you can decide for yourself if and how many you would like.
The batterybox in the trailer or on the rear mount adds a lot of weight to the rear axle of the tractor, to be able to steer the tractor needs a frontweight.
I have tested the model with rechargeable batteries, if the voltage drops it is possible to replace the 12- and 20-tooth gears for two 16-tooth gears (not included in the inventory list). This regains some of the speed without losing to much torque.
Steering the model can be a bit difficult for (small) children. The set has an option to reduce the steering radius by putting two 12-tooth gears on the steering beam as shown in the pictures. The 12-tooth gears can be placed on the trailer when not in use.
The steering system is based on a moc by davejsp.
In the video below you’ll see test drives indoor and outdoor, in different situations.
After taking it outdoor the tires seem to have lost some of their grip on my slippery floor, I think driving in the loose sand has something to do with it. Taking the set outdoor is at your own risk.
The infrared technology from the PF remote can perform less in direct sunshine, but indoors it works very well. Instructions are included for adapting the remote, but if you already have a setup that works well for you it should be fine te use that. I based my adaptation on a design by olivierz.