Original Year	1994
# of pieces	461
Categories	Cars & Trucks: 4x4's
Dimensions	37(L)x20(W)x21(H)
Features	Steering, V-6 engine, front and rear suspension, winch, differential
Other Views

8858 Rebel Wrecker

Click the image to download the LDraw file of this model.
Model by Benjamin Wendl

This beautiful truck, released in 1994, is one of my very favorite Technic sets. It looks great, the size is a nice balance between part count, features, and price, and the suspension is the best you will see on any set. For any size, this truck would be considered packed with features. For its medium size, it is absolutely brimming with them. The rear differential drives a V-6 engine. There is rear trailing arm suspension and front independent double wishbone suspension with an anti-sway bar. The front wheels also steer of course. Finally, there is a ratcheting winch on the back.

With all of these features, you might assume that this model is pure function over form, but that is not the case. There's a wonderful "slammer bar" front bumper, nicely shaped fenders, a reasonably detailed cabin, rally lights on a sturdy roll bar, and those huge tires!

This is one of those old Technic sets that I recommend every fan should own. It is an excellent example of everything that's great about Technic.

Note that the set number, 8858, was also used as an alternate number for the old set 858 in some years. This is one of the few numbers to be re-used.

Features
Steering The front wheels can be steered using an overhead "hand of god" control. This wheel turns a set of 14 tooth bevel gears. The next axle passes through one of the new 16 tooth idler gears (shown in dark gray) before meeting a set of 8 and 24 tooth spur gears. Finally, an 8 tooth pinion mates with the tiny new gear rack. This gear rack has ball joints at either end which attach to steering links. Thes links terminate at the ball joints on the steering control arms. Because everything in the system uses ball joints, the steering is able to function even when the geometry changes due to suspension travel. The steering wheel at the driver's position is not connected to anything.	Click for an animation of the steering in motion.
Drive Train The engine is connected to the rear axle via a fairly convoluted gear system made even more complex by the presence of the rear suspension. The crankshaft turns a 16 tooth gear which mates with a 16 tooth idler followed by another 16 tooth spur. The second gear passes engine torque through, and is the same gear which is located in the steering system described above used as a mere idler. The next gear is an 8 tooth spur but this acts only as a spacer; it is not attached to anything. The location of the universal joint is very important. Since the rest of the system is attached to the movable trailing arm of the rear suspension, the drive system must be able to pivot about the same axis as the suspension. The u-joint allows this. Next, a pair of 8 tooth pinions move the torque to the right into a 24 tooth crown, the first time the gear ratio has changed. This crown mates with the ring gear of the differential, resulting in a total ratio from the engine of (16:16 x 16x16 x 8:8 x 8:24 x 24x24) = 1:3.
Engine The rear wheels are used to drive a V-6 engine. The engine is made from cylindrical engine elements. The two cylinder banks have a standard V angle of 90 degrees. The crankshaft is offset 1/2 stud from center, giving the pistons a stroke of 1 stud. Each pair of pistons shares a common crank pin. Because the crank pins are each offset 180 degrees, the forward and back cylinders are synchronized. This can be seen clearly in the animation. This engine bay certainly is packed with engine. I suspect this truck has a very high power to weight ratio. You can see the massive torque of the engine twisting the frame in the animation!	Click for an animation of the engine in motion.
Differential The rear axle is "live" and use a differential gear which incorporates a built in 24 tooth ring gear (new this year). The differential is made to house 3 of the 14 tooth bevel gears. One is on each axle, and one planet gear in the middle allows the axles to turn at different rates.	Click for an animation of the differential in motion.
Front Suspension This is some sweet front suspension, unparalleled in any other Technic set. Suspension motion is controlled by a double wishbone system on either side which uses the new A-arms, shown in blue. The ball joints at the upper and lower A-arms connect to a control arm with ball joint sockets. This system results in a 4 bar linkage which keep the wheels perpendicular to the ground as the suspension moves through its travel. Attached to the lower A-arms are a pair of shock absorbers anchored to the frame. This allows the suspension on either side to operate independently. The suspension has significant travel, limited only by the bottoming of the shock absorbers. You can see from the computer image that significant thought was put into the attach point of the shocks. The upper end is offset by half a stud using engine crankshaft elements. Finally, there is a third shock absorber which acts as an anti-sway bar. This is attached to a pair of cams and links the right and left side wishbones to each other. The result of this is that some of the force from a leaning vehicle is transferred to the other side. This system also results in a stiffer spring rate when both sides move together than when they move independently.	Click for an animation of the suspension in motion.
Rear Suspension The rear wheels are supported by a pair of trailing swing arms with the large size shock absorbers. Though this makes the suspension itself independent, the live rear axle with a differential effectively links the two sides together. You would need u-joints on either side of the diff to make this truly independent.	Click for an animation of the suspension in motion.
Winch There is a rear boom which rests at a fixed angle using several liftarms. A ratcheting winch is controlled by a crank (literally) on the left side of the vehicle. A pole reverser handle with a bushing on it acts as a pawl, mating with a 16 tooth gear used as a ratchet plate. Another pole reverser handle releases the mechanism.	Click for an animation of the winch in motion.
Wheels and Tires This set uses 4 of the new large 68.8x40 balloon tires and white wheels.

Other Views
Side View	Top View
Front View	Back View
Computer Render

Contact me with comments on this page.

8858 Rebel Wrecker

Features

Other Views