# Wheels

In this step we will attach the caster ball and the wheels.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2F6ef99c5985816d0c6ac6df6cf91ce3ee0950f34b.jpg?generation=1605254928915064\&alt=media)

Prepare the caster housing by cleaning the plastic with alcohol, then lightly place a circle of double sided tape on the caster mount.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2F661a9cae984ec890b6df88d6f255361f78ae04f2.jpg?generation=1605254929908186\&alt=media)

Press the double sided tape onto the caster housing by pressing down on a flat surface. It is important to use a flat surface so the tape doesn't bow through the hole in the housing. If the tape is allowed to bow through the hole, it may stick to the roller ball once added.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2F90fcbb3664a830b927f0aa74c739b66c50d7ff66.jpg?generation=1605254929392547\&alt=media)

Prepare the surface on the bottom side of the lower frame plate with alcohol, then press the caster housing onto the rest of the assembly. Place it in the same general location as the picture.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2F6d40e193ca34565da40fefae621877097d2a0a94.jpg?generation=1605254929165565\&alt=media)

Clip the ball into the caster housing. The ball should spin freely in the housing.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2F36e8435f92d9a04b8b9efd433a95ba965b5f5636.jpg?generation=1605254928782523\&alt=media)

Assemble the wheels. Stretch the rubber tread over each of the hubs.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2Fc85f44b9014d6ce31a0ff35e5e08874c03641bbf.jpg?generation=1605254929762842\&alt=media)

Notice that one side of the wheel hub sticks out further than the other side. The side that sticks out should be faced toward the motor on each side.

Notice there is a slight "D" shape cut into the center of each wheel hub. This hub matches the flat spot cut into the shaft of each motor.

Match up each wheel to each motor and press into place. The wheels should press into place with a bit of pressure.

**Important Note: DO NOT PRESS THE WHEEL ALL THE WAY TO THE MOTOR MOUNT.** There should be a slight space between the wheel hub and the motor mount. This will allow the wheel to spin freely without binding against the motor mount.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2F0cec3b5019fc543da2ec05d91f4df2ad22554192.jpg?generation=1605254929591115\&alt=media)

The wheels should look like this once installed. Notice the bottom sensors sweep slightly forward so they don't bind against the motors.

**Important Note:**

* If you experience the wheels binding up during operation, it is likely that these bottom sensors have moved backward against the wheels. They are fairly easy to re-tighten later if needed.

![](https://3788115009-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MM-dVrbjYKw29N3WLY7%2Fsync%2F939e73f5c3136190151b000e675883d003d0ef4c.jpg?generation=1605254928565665\&alt=media)

All done! It's starting to look like a real rover. :)


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