Can you see what you are really doing to your axles?
Be careful! A recent fellow derby dad sent us a car to evaluate. He could not understand why he did not place as well as previous years. His COG for weight was appropriate at about 7/8″ in front of rear wheel. His car was mostly aerodynamic with no obvious drag designs.
The car was a 3 wheel rider with a steering axle used for tuning. Upon quick observation, I noticed one of the axles had rough edges. I figured that was the main cause of his less than expected performance. So I took off the three wheels and this is what we found. As you can see there is damage on each axle. The tooling used to install/tune each axle permanently damaged the axle by providing rough almost burr like edges that rob your car of speed needed. Every little bit of damage matters when you are talking about .001 seconds from first to second place.
This derby dad was totally surprised when I sent him my findings. He could not believe what damage he had done to his axles.
Recommendations to remedy this common pinewood derby problem
#1 First is to make sure that the bend of your axle happens outside of the area where the wheel spins. A bend in this vital area of your axle causes the wheel to bind as you can imagine the wheel is no longer rolling on a straight plain. Its path around the axle is an elliptical rotation. With each pass of the wheel, the diameter of the inner wheel hub is being wore larger which is making the car drive different with every race. This car will never run the same race twice.
#2 Notice the burrs around the edges. This is caused by improper tooling. Probably a regular set of needle nose pliers were used to adjust. Solution: Pinewood Axle Tuning Pliers
#3 What can also be seen here is that the graphite flake is too large and not soft enough as it is still on the axle without being ground down into the layers necessary to build the friction-less surface. It does matter what graphite you use. The stuff at the hobby store, might not be your best bet.
We highly suggest our graphite which is seen below
