Tuesday, March 19, 2013

Pinewood Derby Car Troubleshooting

So the car is done, you’ve given it a few test runs, and you’re not satisfied with the way it performs. What do you do now? Here are some common symptoms that occur along with some suggestions for correcting the problem.


SYMPTOM: The car starts more slowly than other cars.

CAUSES & SOLUTIONS:

1. Weight has been added to the wheels - Remove the wheel weight and add it to the car body.
2. Wheels do not spin freely - Make sure the wheel-to-body gap is set properly using a wheel alignment tool (or use a dime), and that the wheels/axles are thoroughly lubricated with a recommended lubricant (graphite must be broken in to perform well).
3. Car is not properly staged - Make sure the car is pointing straight down the track, and the wheels don’t touch the guide rail.
4. The car is too heavy (outlaw-type races) - Reduce the weight to something less than 12 ounces (less for short tracks).


SYMPTOM: The car is fast down the hill, but is passed on the flat section of the track

CAUSES & SOLUTIONS:

1. The car is not at the maximum weight - Add weight to bring the car to the maximum allowed weight (typically 5 ounces).
2. The weight position is not set properly - Move weight such that the balance point of the car is at the recommended position (1 to 1-1/4 inch in front of the rear axle for most tracks).
3. The wheels are not aligned - Adjust the wheel alignment such that the car rolls eight feet on a smooth and level surface with less than 1/2 inch of deviation.
4. Wheels do not spin freely - See comments above.


SYMPTOM: The car wobbles back and forth

CAUSES & SOLUTIONS:

1. The wheels are not aligned - See comments above.
2. The axles are too small for the wheels - Refit the car with properly-sized axles.
3. The weight position is set too far back on the car - See comments above.


SYMPTOM: The car makes a chattering sound near the finish line

CAUSES & SOLUTIONS:

1. The weight position is set too far back on the car - See comments above.
2. Wheels are not properly lubricated - See comments above.


SYMPTOM: The car hugs the guide rail

CAUSES & SOLUTIONS:

1. The wheels are not aligned - See comments above.
2. The wheel tread is beveled - Replace the wheels with flat tread wheels (be aware that ‘Speed Wheels’ from some suppliers have slightly beveled tread).
3. The track is not level - Adjust the track.


SYMPTOM: The car jumps the guide rail

CAUSES & SOLUTIONS:

1. The car has a raised wheel which is too high - Set the raised wheel no more than 1/16 inch higher than the other wheels.
2. The wheels are not aligned - See comments above.

FINAL THOUGHTS
This article covers many of the problems that are encountered with pinewood derby car performance. But if you run across another problem, please send me an email and I’ll be glad to assist with some causes and solutions. Good luck with your race!

From Pinewood Derby Times Volume 5, Issue 12

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