[Andrew Rudolph]

I think that there were some im the FIRST gearbox last year, maybe I am wrong. I know that they are used to hold the wheels on for powerwheels, and if you have ever taken them apart you would also know that means they hold the wheels and motors on. There are aluminum shaft collars, and even nylon and ABS plasic ones, so if you want to sue them for simplicity, then there are lighter alternatives than to using steel ones. Also to make it easier to pull them off just keep a few T handle allen wrenches in the correct size, then more than one person can pull them off, and there are a number of styles, the easiest to put on and off if you can is the 2 piece clamp on style. Look in McMaster there are a number of different styles and materials.