Lloyd E. Sponenburgh wrote in article
...

"John Blinka" wrote in message
. ..
Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication.

I think you'll find the pinewood rules limit the all-up weight to 5oz. I

know that used to be the limit.

One thing I noticed about the winners back when I was the Cubs district
chairman here was that they all had nearly flat wheel profiles... that
is,
the part touching the track was flat all the way across, rather than
crowned. I even tested those two alternatives, and flat seems a bit
faster.

My theory is that a crowned wheel tends to "fall into the cracks"...
actually the grain, on the plywood tracks, while a flat profile runs over

the tops of the cracks.



I would suspect that the flatter wheels with a more-stabilizing footprint
ran more true vertical - keeping them from flopping around in their loose
fit on the axles.....