I am to build a mouse trap car that goes the longest distance. From what I understand, I want to increase the distance by using a looong arm that I attach to the arm on the mousetrap. I want the string to only be hooked onto the axle so that it lets go when it gets to the end. I want a SMALL axle to wheel ratio in the back atleast. I am using 2 CD's for my back wheels, and a simple Victor mouse trap. The thing I am trying to figure out is this: What material am I going to use for the axle and arm? The arm only needs to be light, yet sturdy (and long)... The AXLE on the other hand, needs to be light, as small in diameter as possible, while still being able to get some sort of hook into it so that hte string will let go at the end of it. In conjunction, I need to worry about the ... part that the axle will go through on each side: Obviously using a wood axle with a wood frame would cause some friction as it turns. But I've had trouble finding extremely small (nylon) bearings, along with an axle that would fit them. The other thing I need to worry about (slightly less so, but still) is this: the string that pulls the wheel. I figure fishing line is strong and light. Will that work? Please be aware! I am not simply coming on here and asking for you guys to do my whole project... I HAVE built a model out of lego pieces so far, and that went about 2 meters with a 9" arm, and extremely wide wheels (with half the diameter of a CD), so I have had some success in this so far, but in building the REAL thing, I need to decide what materials I will use since I will likely need to go to several differnt stores to find them. Thanks in advance!