Free Rotation Wheel

[zizou244]

Hello Guys !

I'm currently building a 4 wheeled car and I'm trying out a differential drive with the Two Rear wheels connected to DC motors, and two Free rotating front wheels.

I'm curious what kind of simple mechanism I could use to get the "free rotation" part. I only know about the bearing system you can find in this kind of wheel :


The wheel you can see in the picture has some kind of ball bearing.
Do you know of any other "simpler" way of ensuring the free rotation around the Z axis ?

PS : The car i'm building is a little big, and the wheels I'm using came from an old baby stroller (15 cm diameter and a 1cm hole in the middle)

[mklrobo]

  Hello!
In reference to your wheels selection, I would check out some of the vendors in this forum;
like ServoCity. Some of these vendors have some mind-blowing wheels,  that turn
in an unconventional way; and they are priced reasonably. Check them out! 

[Ibaeni]

It's also very common to put some low friction piece of material as a third point of contact. Something like a bottle cap would even work.

If you want something a little nicer, you could get a ball caster. It is essentially a marble in a holder that can roll in any direction. They're relatively inexpensive on Sparkfun.