CO₂ Car Wheel Assembly

Once your car is painted, it is time to assemble the pieces.

Wheel Assembly

Materials:

Plastic straw - reduce friction between axle and body of vehicle

Metal rods - axles

Washers - reduce friction between body of vehicle and hubs

Eye screws - keep car on track while racing

Wheel Assembly

Procedure

Plastic straw

1. Check to see that the straw will slide easily into the axle hole that has been drilled. If it does not, re-drill the holes.
2. Cut the straw length so that it is only as long as the width of the car at the axle hole. The straw should line the hole, but not stick out from the sides of the car.
3. When the straws are the correct length, insert them into the axle holes.
4. The less friction you have between any of the moving parts of your car, the faster it will race. Check to see that no rough cut edges of the straw are sticking out of the axle holes.

Wheel Assembly

Procedure:

Metal rods - Ideally, the metal rods will be long enough to extend past the body of the car just far enough to attach the wheels. It may be possible to cut the axles if they are too long. Ask your teacher about this. It may also not be possible. Be prepared to proceed either way.

If you are able to cut your axles to size:

1. Place the axle through the axle hole and attach one wheel. Determine how much the axle will need to extend past the body of the car in order to attach the second wheel without the hub rubbing up against the body of the car.
2. Mark the axle where it will be cut. Do this for both axles.

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Wheel Assembly

Procedure:

Cutting metal rods

If you are checked out on the dremel with the metal-cutting attachment, you may be approved to cut your own axles. This is unlikely, but check with your teacher. Otherwise, your teacher will cut your axles for you.

Once your axles are cut, all sharp, metal edges must be removed. Your teacher will do this if she cuts them for you, but let her know if she missed any.

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Wheel Assembly

Procedure:

Assemble wheels

1. Once you have your axles cut to length (or not), slide one into the rear axle hole.
2. Place a washer on the axle so that is up against the body of the car.
3. Attach the wheel.
4. Repeat steps #2 and 3 for the wheel on the other side.
5. Repeat steps #1-4 for the front axle using the front axle hole.

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Eye Screws

Procedure:

Eye screws

The eye screws serve to keep the car on the track when it is racing.

1. Flip your car upside down.
2. Find the center of your car and draw a line lengthwise down the center.
3. Find the spot along that line that is lined up with the front axle.
4. Make a mark 2mm either ahead or behind that point. Make sure your mark is still on the center line.
5. Using a sharp nail or wood screw, make an indent by pressing the point of the nail or screw into the mark you just made. This will make it easier to screw in the eye screw.
6. Repeat this along the center line along the rear axle.
7. By hand, screw in your eye screws at the two indents you made. If you are having trouble holding the eye screw while screwing it in, you may want to hold it with some pliers.
8. Screw the eye screws in so that the entire threaded part is embedded in the wood.
9. Make sure that the eyes are aligned so that you can see through the center of both of them at the same time if you look from the front to the rear of the car.

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You are now ready to race!

Before you race, you will need to calculate your predicted rate of acceleration.

For instructions on how to do this, return to the original slide deck:

CO2 Racing Car

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