Tamiya Unimog Project

Page 1: Assembly

The CR-01, despite being a "newer" model, come in a box with nice old school art and internal dividers for presentation. When the box is opened you see a smaller box of hardware, the substantial tires, the metal chassis rails, and the clear body.

The side rails are really nice formed channels with many drilled holes allowing a variety of mounting options. The box in the back is very heavy and contains all the hardware and metal parts including gears and axles. As usual for Tamiya kits, bags are labelled A through D to correspond to sections of the instructions so you only need to open what you need.

The cantilevered suspension on this model is very unusual. Instead of having vertical shocks connecting the axle to the frame, there is a vertical pushrod which connects to a two-piece crank arm. The crank arm then attached to the shocks which are mounted diagonally along the frame. The two pieces of the crank are connected via a hex shaft with some clearance in it which results in slop between the arms. I later corrected this by adding a small diagonal link between the arms to lock them together.

The crank assemblies are attached to the frame rails and so are the plastic side plates. The battery tray and electronics platform serve as cross members. At this point the frame is pretty flimsy because the sides are only connected at the top.

The front and rear axles are identical if you build them with the four wheel steering option. At this point (prior to upgrades) I did front wheel steering only. The model has front and rear differentials, but per the instructions they are built locked. They can be unlocked by removing a set screw.

The 8 suspension links are nice aluminum threaded shafts with plastic ends using large steel balls. The links attach to the side plates of the frame, not to a center member like most other 4-link setups.

The shocks are unusual in a couple of ways. Most obviously, they are installed diagonally on the side of the frame instead of in their usual position. They are driven by crank arms. They have no coilover springs. Instead, the springs are attached separately where the shocks would usually be. Finally, they actually extend as the suspension is compressed which is the opposite of the usual arrangement. The shocks themselves are plastic oil filled units which are not unusual.

Most kits start with the gearbox, but this model saves it until last. The center of the gearbox is a planetary system with three planet gears on a plastic carrier. This is the only stage of reduction apart from the pinion/spur combination which makes for a compact gearbox. The silver can motor is then attached to a metal motor plate along with the drive shaft ends.

When the gearbox is attached to the chassis it connects the frame sides at the lower end and finally stiffens everything up nicely. This is a very durable model. The front bumper and end cross members have also been installed to close out the frame. I've installed a temporary power system to try it out until the last of my upgrades arrive. The body posts will be trimmed to fit the Unimog body.

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