Originally posted by: badkarma1399
Originally posted by: DrPizza
Tip: reducing friction in the wheels is the MOST important part of a pinewood derby car. If you used the little nails that came with the kit:
remove the nails.
put them in a drill chuck
turn drill on
polish "axles" with emory cloth. Bevel the head of the nail so that the sharp edge doesn't grind against the wheels
Replace the "axles"; lubricate with graphite.
edit: sand the inside edge of the wheels where they might rub against the car; get it as smooth as possible; lubricate this as well.
What I also did ...erm....with help from my dad, was to reduce the axle's diameter for
just the part that was over the direct center of the wheel. The wheel would then only touch the axis at the wheel's front and back, but there would be no/little contact with the center of the wheel and the axle.
We also balanced it so it would only use three of the wheels, as opposed to four. Won first place two years in a row.
I bought some axles off the internet last year that were lathed like that because I don't have access to the equipment to do it. It also helps because it allows more lubricant between the wheel and axel. We didn't do the "3 wheel" trick because it was specifically against the rules (though noone ever checked).
I think I spent about $50 getting supplies and such off the Net last year
. Normally I am all about letting the kid do as much of the work as is safely possible and stressing that the learning is more important than winning. But last year my oldest was mad because our effort the previous year wasn't that great (we finished midpack pretty much), though he did a good job as he did most of it himself. So he implored his contractor uncle to work with him last year instead of me. It became a contest, as my middle son was up for his first PD race. I still had him do a lot of the work but I took more consideration with design issues and getting the axles just right.
We smoked them
. We ended up with the fastest car in all the age groups for our Cub Scout Pack, but we never went to the district race.
Another tip that helped a lot: we took out a notch from the front, and put a spoiler-like device in its place. When the pin drops on the track as the race starts, the pin slides past the spoiler and through the void from the notch, so there's nothing holding the car from going down the track. The other cars are still being held back by the pin for a tenth of a second or two (guessing, not scientific). Our car would end up with an inch or two head start.
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