LWB vs SWB Tamtech Chassis

There are two chassisî of the Tamtech road family:

– long-wheelbase chassis with an interest of 116 mm,
– short-wheelbase chassis in which there is the possibility of changing the distance between the front and rear axles by approximately 7 mm, from 97 mm to 104 mm. The image on the left shows how to set up the short wheelbase chassis with 97 mm wheelbase by installing the drive train axle – transmission in the blue point, and on the right shows how to set up the short wheelbase chassis with 104 mm wheelbase by installing the drive train axle – transmission in the red point.

The point at which the ball joint of the rear suspension links is bolted to the centre shell also changes.

The three step alternatives are as follows starting from the longest one on the left and moving towards the shortest one on the right, the width also changes by 1 mm:

The variety of wheelbases makes these chassis suitable for installing a wide variety of body in 1/24 scale. In theory, it is possible to adapt many of the static bodies to the Tamtech chassis. This guide shows how to assess the technical feasibility of installing a static body on a Tamtech chassis.
These models are so compact that they are smaller than the Futaba Attack remote control that completes their electronics. Despite their small size, there are many parts that make up the chassis and body; the picture shows all the parts that make up the Lancia LC2 model number 48002.

The differences between the short and long wheelbase chassis are many, and this is intended to be a list of the main parts that change from a short wheelbase model to a long wheelbase model; it is not an exhaustive list because the differences are many more.
The long wheelbase was the first of the two models to be released, and the short wheelbase is an evolution of it; you realise at the end of the comparison that the differences are so many that it is conceivable that the two designs are two completely different strands of the same basic idea. It is quicker to list the parts in common between the two models:
– gears and differential (in pink in the picture),
– pinions,
– FK-180SH Mini-Black motor (in red in the picture),
– ball-bearings,
– front suspension springs; there are two pairs with different hardness (in purple in the picture),
– rear suspension springs (in orange in the picture),
– rear wheel hub (in blue in the picture)
– 2 front wheels and rims (in blue in the picture),
– 2 rear wheels and rims (in green in the image),
– 2 steering system dies (in yellow in the picture),
– transmission axle (in sand in the picture),
– antenna holder (in dark green in the picture),
– electronics consisting of CPR unit, remote control, servo and Tampack battery pack.
In the pictures below and all the following ones on the left is the long wheelbase and on the right the short wheelbase.

The central body of the chassis is different between the short and long wheelbase models. The difference in the two shells leads to changes in all other parts of the machine from the steering system to the rear motor-transmission unit.
The biggest difference is the position of the CPR unit; in the long-wheelbase shell the electronics unit is installed more towards the centre of the car, whereas in the short-wheelbase shell the electronics unit is moved more towards the rear.
This shifts the centre of gravity towards the rear, improving traction but worsening steering precision. This partly explains why the short-wheelbase model is less driveable and manoeuvrable than the long-wheelbase model.
The two plastic tabs that hold the CPR ECU are at the front of the long-wheelbase chassis shell and at the rear of the short-wheelbase chassis shell.

The front assembly comprising steering and suspension is different, but provides the same functionality. The servomotor that controls the movement is the same for the two models. In the short wheelbase version, the servomotor is more exposed to frontal impacts as it is not protected by the central shell. The action of absorbing asperities is entrusted to two springs installed one for the right and one for the left drum, a very simple system that does not take up much space.

Although the short-wheelbase chassis is an evolution of the long-wheelbase version, it has always suffered at the rear. The ball-joint suspension arms have been changed from 3 mm in diameter (red parts in the picture on the left) to 2 mm in diameter (blue parts in the picture on the right) and tend to disengage easily.

The rear suspension-motor system is different between the two families; the design of the short wheelbase has led to modifications compared to the long wheelbase and the stabiliser bar tends to lock up, reducing the excursion of the drive unit, impairing driveability and losing handling. The picture shows the two plates that form the rear system that houses the motor, transmission and differential.

This completely changes the entire power unit, which also includes part of the suspension system.

The system for switching the long wheelbase model on or off involves a thumbwheel that turns electronics off or on.

The on-off contact system on the short-wheelbase version is an evolution of the one found on the long-wheelbase version; pressing switch turns the machine on and pressing switch again turns it off, in normal operation it could change state by switching the machine off.

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