The current Racer Mini 4WD was introduced after the evolution of the Mini 4WD series developed by Tamiya in 1982. Two series of Mini 4WD have been launched in the US market in 1997: a racing oriented Super Mini 4WD series, and a Fully Cowled Mini 4WD series.

A cement-free snap kit, Tamiya Mini 4wds are basically "plastic model kits". Many upgrade parts are available for performance improvement. For example, using optional ball bearings helps in minimizing friction loss and utilizes motor power more efficiently. Selecting the right upgrade parts, you can enhance the performance of your car's stability in curves and acceleration.

Another enjoyment in "tuning-up" besides enhancing performance is that you can create your own machine by customizing it. You can get creative while tuning up your car. Try hollowing out your car to make it lighter or painting it with vivid colors.

The excitement you get with Mini 4WD is as great as the one you get with Radio Controlled Car racing. The Mini 4WD gives you the excitement of racing as if you were a car designer, engineer, and racing driver.

Mini 4WD snap kits are reasonably priced and can be considered a learning experience for many kids. They are easy to assemble and objects of pride and accomplishment for children and their parents. Through assembling their own cars and racing them, children will be able to gain a sense of competitiveness and creativity. Fun and learning can be had at the same time!


Mini 4WD Basic Knowledge

You can enhance the performance of your cement-free Mini 4WD by using Tamiya's various upgrade parts and provide it with increased power and faster speed. To do this, you need to know the basic element of the Mini 4WD.


Motor

Installation of tune up motors is the best way to increase the speed of your car. There are seven kinds of motors available for upgrade. All of them achieve higher performance than the standard motor included in the kit. It is essential to select the right motor since some are designed for top speed, while others are set up for cornering.


Gear Ratio

At a given output power of the motor, top speed and acceleration is determined by a gear ratio. In the comparison between a 4:1 gear ratio and a 5:1 gear ratio, the smaller 4:1 ratio is more suitable for speed oriented circuits, while the bigger 5:1 produces more acceleration.


Performance Difference Among the Various Gear Ratios

Different gear ratios are available for your choice. Use a small ratio for straightway courses and a big one for technical courses with many curves and ups-and-downs. Set up gears according to the track you are racing on.

Tires

Tires are an important part of your car and have a great influence on its performance. In combination with the wheels, weight, diameter, and width should be considered according to the type of course you are running.


Difference in Diameter

Small diameter: Good for a quick start, but not for top speed. Small diameter tires lower the center of gravity and helps your car corner better.

Large diameter: Good top speed and suitable for straightway. Better shock absorbing for bumpy course joints.


Difference in Width

Wide tires: Provides stability during cornering. Good for technical courses with up-hills, curves, and ups-and-downs.

Narrow tires: Good for straightway courses. Less drag on the motor and may have the advantage of longer run times.


Difference in Material

Rubber: Included in a snap kit. Weighs more than the sponge type, but useful for jumps and lowering the center of gravity.

Sponge: Weighs less than rubber type but with lower grip characteristics.

Reston: Lighter than the regular sponge type and better gripping. Good speed stretch. Can be used for all kinds of wheels.


Tire Maintenance

Use transparent tape to clean sponge type tires. Clean rubber type tires with an eraser and remove the eraser pieces with tape.

Wheels

Wheels, as well as tires, play an important role in tuning up your car. There are various types with different diameters and structures. Select the right one for your application. All of the different sized wheels can be used for the Super Mini 4WD series, however, if you have a Fully Cowled Mini 4WD, body modification will be required if you use anything other than the standard, small-diameter type wheels.


Types of Wheels

Small diameter type: Narrow Wheel which is a standard for the Fully Cowled Mini 4WD, Wide Super Low-Height Wheel, Wheel for semi-pneumatic tires.

Large diameter type: Included in a Super Mini 4WD snap kit. Lots of designs are available pick your favorite.

One Way type: Light One Way Wheel, Wide One Way Wheel, Low-Height One Way Wheel, Narrow One Way Wheel (exclusive for the Fully Cowled Mini 4WD).


Normal Wheel vs One Way Wheel

Normal: The speed of the wheels at both sides of a car is the same. This is good for the straights, however the outer wheel tends to be dragged during cornering and this may slow your car down.

One Way: The outer wheel rotates faster than the inner wheel does. Ensures smooth cornering and is preferred for technical courses with many curves.

Rollers

Rollers are a must when racing on walled circuits. They help your car negotiate corners smoothly. Key points in using rollers is their size, location and angle.


Handling Settings by Roller Size

Same size: Standard setting. Front and rear rollers have the same diameter. This makes your car easier to run straight since rollers are lined parallel when they contact a wall. Also minimizes power loss.

Bigger in front: Front roller diameter is bigger than that of rear roller. Suitable for courses with many corners since this pushes your car towards inside of the course when rollers contact a wall.


Smaller in front: Rear roller diameter is bigger than that of front roller. This makes your car run along with a wall. Gives stability during cornering, but creates power loss.


Racing with Mini 4WD

The true appeal of Mini 4WD can be found in racing them. Many kids compete in events put on by their local retailer. It is as exciting as real full size racing. Bring your own Mini 4WD and see what you can do. In 1997 Tamiya Mini 4WD Racing Tour will be held in numerous locations across the US.


There are formal rules and regulations for the Tamiya Mini 4WD Racing Tour. This makes the racing consistent and fair. The excitement of Mini 4WD racing is not just making them go fast. It is in analyzing and improving your car, expressing your creativity and making new friends. This is what sets Mini 4WD racing apart from many of the other activities available to youngsters today, and what has made mini 4WD one of the fastest growing hobbies in the world!


- Source: Tamiya.com