Tamiya BBX Project

Page 1:  Assembly


   

The BBX comes in quite a large box which is separated on the inside as shown.  There are no blister packs, but the body is in a separate spot from the plastic parts, and the hardware has it's own inner box.  This model gets real, old fashioned, hand drawn box art!


     

As usual, I laid out all the parts on my build table as shown.  There are five sequential hardware bags and a large number of plastic parts sprues.  Pretty much all of the plastic is Nylon (polyamide), but most of the structural parts are glass filled.  On the right I show the contents of hardware bag A which will built the gearbox and motor mount.


   

Here are the three shafts making up the gearbox.  On the left is the ball differential which uses Imperial sized balls (3/32") which is unusual for Tamiya.  The center shaft holds the idler gear.  The right hand shaft is the input which will connect to the spur.  The spur gear is 48p (not metric) as well.  On the right I've installed the gears into the housing and mounted it to the plastic chassis tub.  I've also installed a temporary brushless motor until the right one arrives.


   

Hardware bag B contains parts for the rear suspension and steering.  On the right you can see the dual bellcrank steering linkage installed along with the steering servo.  Note that a low profile servo is required and uses a high torque servo saver.  The steering links are turnbuckles.


   

The four links shown on the left are the lateral supports for the rear trailing arms.  The link length is not intended to be adjustable.  On the right I've installed the link assembly onto the chassis.  The angled plate above the area is intended for the speed controller.


   

Hardware bag C is for the front suspension and the beginnings of the roll cage.  The right hand image shows the front roll cage which spans to the front bumper and has numerous cross members.  The driver figure serves as a cover for the receiver.  The battery slips under the driver by removing the lateral aluminum locking bar shown.  The whole driver platform has to be tilted up to access the battery.


   

Here I've installed the front suspension.  The upper and lower arms are both wishbone type which provides excellent support.  There are ball joints in the end to support the steering knuckles.  The shock towers are separate plastic supports which are quite thick.  The front bumper is minimal and does not protect the suspension arms.


   

Hardware bag D is for the shocks and axles.  The shocks have aluminum bodies with plastic caps and rod ends.  The shock bodies are not threaded, so preload adjustment is done with a clamping collar.  The front axles use quite a lot of preload as can be seen in the picture on the right.  The front shocks install between the wishbone of the suspension arms which makes for a much stronger installation than a typical cantilever.


   

The rear shocks connect to the trailing arms which pivot off of a joint in the roll cage.  There is a nut trapped in the roll cage for strength at this joint.  The steel axles are CVD type at the outer end and dog bones at the inner end.  In the right hand photo I've also installed the rear roll cage above the motor and gearbox, and the side cages which protect the trailing arms in the event of a rollover.


   

The tires and wheels are new and (so far) unique to this vehicle.  The wheels have a chrome finish and the tires have nice internal foams for support.  The right hand photo shown the completed rolling chassis.  The buggy would actually look very good just like this with no body at all.


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©2026 Eric Albrecht