Graphite Coated Pinewood Derby Wheels

This one is interesting.  I would like feedback from those who have purchased such wheels.

Theory suggests that this should be a faster than stock wheel.  One needs to be especially careful on what the graphite and “other” content.  From looking at pictures, there is an awful lot of “silver” tint on the wheels.  Quality graphite leaves a dark grey luster when properly worked in.  So is it graphite coated or moly coated?  If the outer wheel tread is treated, then this should lower the coefficient of friction between the wheel and the track, thus attaining faster speeds, especially toward the end of the track is what the working theory is.

I disagree 100%.  You actually need friction to bite on the track.  Otherwise, if you have this slick (friction-less) surface,  there will be wobbles because there is no friction to keep the wheel from slipping.  Slipping pinewood derby wheels cause side to side travel.  If you are going fast enough this could cause the “death wobble”  The wheels can not “bite” the track to keep it running.  It will be similar to a spin out of drag cars when their tires are slick from their initial “burn out”.  The slick surface causes an uncontrolled sideways motion.  Same goes for a pinewood derby car.  Super slick wheels are NOT the key to winning.  This is why wet sanded wheels need to be about 600 grit and stop.  Anything above that is a little too much.

Evidence based facts:  Graphite only reduces sliding tangential forces, not perpendicular rolling forces. But it may be that there are electrostatic forces generated in the “make and break” rolling action similar to other well known triboelectric effects. The clean polystyrene wheels will hold static charges because they are good insulators, but a solid coating of graphite, which is a conductor like aluminum, would likely prevent electrostatic effects. Be aware that graphited wheel surfaces compromise wheel stability in the y direction (crosstrack) allowing the rear end of cars to possibly begin “fish tailing” with center strip bumping and overall loss of speed. Note also that wheel stability in the y direction is independent of the surface contact area, i.e., a ridged surface slides cross-track just as easily as a wide smooth wheel surface does (This is described fully in the Physics of the Pinewood Derby book).

If coating a wheel was the winning edge for PWD, you would read all about coating an entire wheel with some sort of friction free solution on the pro racing forums.  Guess what’s not there…. Graphite coated wheels, nano coated wheels.  Cyro freezing wheels.  None of that matters, they have tried.  This is all that needs to be said about the matter.

Back to “graphite” coated wheels.  Moly on the other hand leaves a nice shiny “silver” color on black plastic.  Moly has a higher coefficient of friction than graphite.  As discussed in the DRY LUBE section, when moly is added, one can no longer build layers of lubes.  It becomes a single layer application.  Moly is only beneficial in HIGH heat, HIGH pressure, HIGH friction loads.  5oz rolling pinewood derby car NEVER even comes close to any of these thresholds.  Probably would even register on the scale because a load exerted by a gravity fed PWD car is non-existent.

The focus of treating wheels needs to be the inner bore, and the axle head location. It matters, and read all the forums about the special sauces and the OTC purchases prior to the special sauces.

Just my 2 cents to save you a few bucks.  That is all.