I am trying to build a vehicle that has wheels that only spin in one direction--forward. I know there is this device that I can attach to the axle or wheel to allow for the shaft to only spin in one direction and not spin in the other. What is this part called? (I need to know in order to be able to order it online)

Thanks.

you will have to get like a 1 way bearing.Theyt do make them large.

thanks.. i've been looking for this... :p