Where should the center of gravity be on pinewood derby car?

Flat top disc (no dome)
3.0 oz - 7/16" high

Slotted Tungsten Discs

These discs have a slot in the bottom which has several uses as described below.

These discs can be inserted in a 1 inch hole. The hole can be drilled with a spade bit or a forstner bit. The forstner bit is recommended as there is less chance of cracking the block and it results in a cleaner cut.

The weight should be placed so that the car's center of gravity is one inch in front of the rear axle. To check the center of gravity, place the two front wheels and axles on the top of the car over the front axle and the weight near the rear of the car. Place a pencil across the bottom of the car one inch in front of the rear axle then move the weight forward or backward until the car balances.

Center of Gravity Adjustment

Fine tune your car's center of gravity

For this technique to work, the body of your car near the rear axle should be the thickness of your weight plus 1/4 inch to leave room for the axle slot. Your pinewood derby car will go faster if the center of gravity is as far back as possible. But, your car will tend to raise its front wheels and jump off of the track if the center of gravity is too far back. You should have a track available to adjust the center of gravity. Test tracks are available here. Use the above method to determine the position of the weight but the slot should be towards the rear of the car.  When you have determined the position of the weight, drill the 1" hole the depth of your weight. Place the weight in the hole with the slot to the front of the car. Test the car on your track. If the car wobbles excessively or jumps off of the track, rotate the weight slightly and test again. Repeat until the car is stable. Glue the disc in the block with the slot facing down. Use super glue, epoxy or gorilla glue.

Weight Adjustment

Two 1/4" tungsten cubes can be added to the disc slot for an additional 1/3 oz. The body of your car near the rear axle should be the thickness of your weight plus 1/4" to leave room for the axle slots. Drill the 1" hole then complete your car including adding the wheels and axles. Put your pinewood derby car on a scale and place the disc on top of the car. Add one or two of the cubes until the car weighs 5 oz. Tungsten putty can also be added if more weight is needed.  Glue the disc and cubes in the block with the slot facing down. Use super glue, epoxy or gorilla glue.

For Use In Cars With Minimum Wood

The disc can be installed in the bottom of the car so that the slot provides clearance for the axles. One 1/4" tungsten cube or tungsten putty can be added to the slot if more weight is needed. Drill a one inch hole centered 1/4" behind the rear axle. Drill all the way through the car if the car is the same height as the side wall of the weight or drill into the bottom of the car if the car is thicker than the weight.

Axles

What are pinewood derby axles made of?

The official BSA axles are manufactured using a metal stamping process. This requires that they be made of a soft steel. The axles are zinc plated to minimize corrosion. The stamping produces crimp marks on the shaft and axle head that should be removed.

Are grooved axles really faster than non-grooved axles?

Both axles are the same speed if no lubricant is used. Grooved axles have a smaller surface area but this advantage is offset by the increased pressure on the remaining surface. The results change if a lubricant (dry or liquid) is used. Now the smaller surface area of the grooved axle has an advantage because the lubricant reduces the friction caused by the extra pressure. Our tests have shown a gain of about 4 inches at the finish line when grooved axles with a lubricant are used.   More about our axles

What is so great about graphite coated axles?

We developed a special process that bonds the graphite to the axle. The result is an even distribution of graphite along the length of the axle shaft that results in faster speed than loose graphite and lasts much longer. Our tests have shown no reduction in speed after 20 races! For extra speed, add some loose graphite before the race.

Should I insert the axles in the block at an angle?

There is an advantage to angle the axles but it is difficult to insert the axles at the proper angle so axles should always be inserted straight into the block. It is best to bend the axles slightly (1 to 2 degree) then insert in the block. The bend should be at the point that the axle exits the block. Several tools are available for bending the axles the proper amount and at the correct point. insert the axles so that the bend is up.

Wheels

How big are pinewood derby wheels?

Pinewood derby wheels are 1.185" in circumference. The wheel tread is .313" wide. A typical wheels weighs 2.6 grams.

Should I sand my pinewood derby wheels?

In the past, pinewood derby wheels had a mold mark on the wheel tread that had to be removed by sanding. The new wheels no longer have a mold mark.  Sanding can still help by removing variations in the wheel circumference making the wheel rounder but sanding is no longer as necessary as it was.

How close should pinewood derby wheels be to the car?

The hub of the wheel should be a credit card thickness (about .03") away from the car block but can be as much as .1".

How long should pinewood derby wheels spin?

A long spinning wheel has less friction so the longer a wheel spins, the better. A good wheels will spin for around 20 seconds but the spin time can vary with the type of wheel, lubricant and with the amount of force used to start the spin.  For example, wheels that have plastic removed to make them lighter won't spin as long as unmodified wheels but the lighter wheels are faster. Spinning is useful when comparing the four wheels in a set. You should replace a wheel that spins less than the others. To spin a wheel, put the wheel on an axle, hold the axle level then give it a spin with your finger.

What are the best pinewood derby wheels?

The best wheels are round and light. If your race rules allow it, you can sand your wheels or, better yet, put them on a lathe to make them round.  The next step would be to remove plastic from the inside of the wheel to make it lighter. This is best done with a lathe so that the wheel doesn't become out of balance. We offer a variety of sanded and lathed pinewood derby wheels.

Will my car be faster if I raise one of the front wheels?

Raising one of the front wheels so it doesn't touch the track will make your car faster. First, mount all the wheels on your car then push your car on a flat surface. Your car will steer slightly left or right. Raise the wheel that the car is steering toward. The easiest way to raise a wheel is to lower the opposite wheel. Follow these instructions to raise a wheel.

Lubricant

Which lubricant is best, dry or liquid?

Our liquid lubricant (Krytox 100) is better than dry lubricants such as graphite. It is faster and lasts longer. The trick is to use a very small amount of the liquid. You want a very thin film on the axles.

Most Pinewood Derby car races prohibit liquid lubricants because the liquid can drip onto the track.  If you use a liquid other than Krytox, be sure to test it first - some liquid lubricants can soften the plastic wheels.

We tested every available dry lubricant and the Hob-E-Lube that we sell is the fastest. It has a small amount of molybdenum mixed with the graphite for better lubricating characteristics.

Can liquid lubricants be used with the the graphite coated axles?

No, liquid lubricant and graphite don't do well when mixed.  You should add loose graphite to our graphite coated axles just as you would the standard axles.

Should I lubricate the wheels before or after they are on the car?

It is a lot easier to lubricate before they are on the car but you should also add more graphite just before the race. Instructions for lubricating the wheels can be found here.

How soon before the race can I lubricate the car?

If you are using graphite then there is no time limit on when you can lubricate your car. Just keep your car in a shoe box after lubricating until the race.

If you are using oil, the oil will slowly evaporate over time so you should lubricate the car within a week of the race. Keep the car in a shoe box until the race.

What else can I do to reduce friction?

A large source of friction is the rubbing that goes on between the wheel and the Pinewood Derby car body. Some people angle the axles up in an attempt to keep the wheel away from the body. A better solution is our graphite pads. These are 1/4" self adhesive pads that are placed over the axle hole on the body. The axle is placed through the center of the pad. Now the wheel will rub against the pad instead of the car body greatly reducing friction.  Our tests have shown a gain of about 7 inches at the finish line when using graphite pads. 
More about our pads

Pinewood Derby Car Design

How big is a pinewood derby block?

The dimensions of a pinewood derby car block are 7 inches long, 1 3/4 inches wide and 1 1/4 inches high. The official BSA block is made from ponderosa pine.

Should I bake the pinewood derby block?

The short answer is no, do not bake the block. The idea behind baking the block is to remove moisture which will make the block lighter. You can then add more weight to the back of the car.  The risk with baking is that you could warp the block. Also, the blocks have already been kiln dried so all excess moisture has already been removed. Baking might remove more moisture but the block will quickly re-absorb the moisture after it is out of the oven and cooled down.

What model scale is pinewood derby car?

The pinewood derby block is 7" long. The scale is approximately 28:1.

How do I cut a pinewood derby car?

A band saw is by far the easiest tool to cut a pinewood derby car. If you don't have access to a band saw then a coping saw will work. Coping saws are inexpensive and available at hardware stores and online. Learn more about using a coping saw. Both the band saw and coping saw can cut curves and other shapes. For a simple wedge block, just about any kind of hand saw will work.

Which pinewood derby car shape is the fastest?

The fastest pinewood derby cars have more wood in the back and very little in the front.  All else being equal, the car on the right is faster than the one on the left. The goal is to move as much weight to the rear of the car as possible. The ultimate car would have very little wood with tungsten weights placed behind the rear axle. When completed, the car should balance about 1 inch in front of the rear axle. We have a wide variety of pre-cut cars made from the official pinewood derby blocks that can make building a pinewood derby car much easier.

Which end is the front of a pinewood derby car?

Either end can be the front of the car but the end of the block farthest from an axle slot gives you an advantage if it is the front of the car. The reason for this is that you can put weight farther back on the car if the rear slot is close to the end of the block. The car will be more stable and your car will go faster with the weight farther back.

Can a pinewood derby car be shorter than 7 inches?

Yes, you can make your car shorter but it is not recommended. A shorter car will have a lower center of mass at the start so it will have less energy to convert into speed when going down the track.

How long does it take to build a pinewood derby car?

Plan on at least one day to cut and sand the car, another day to paint it and a third day to add decals and the wheels and axles.

The hardest part about making a car is cutting the wood. All of our car designs use only straight cuts and this simplifies construction. Our plans give step-by-step instructions and a lot of diagrams to show you how to do it. Some people trace the design on the side of the car (using the included templates) then take the block down to Home Depot or a hardware store and ask them to make the cut. More about our car designs

Are axle holes better than axle slots?

One of the big problems with slots is that it is difficult to insert the axle so that it is level. If your rules allow it, axle holes are the way to go. You can use a #44 bit and a drill press to drill a hole next to each slot an 1/8" from the bottom of the car block. A drill press should be used to drill the holes. The holes can also be drilled with a hand drill if you use our Pro-Body Tool to guide the drill. If your rules specify that you must use the slots, our Pro-Axle Guide will make sure that the axles are inserted properly.

What makes pinewood derby cars fast?

Here's what you can do to make your car faster:

• Axles - Deburr and polish the axles. Axles should be straight.
• Wheels - Check that your wheels are round and don't wobble. Light wheels are faster.
• Weight - Car should weigh 5 oz. Weight should be placed near the back of the car.
• Alignment - Car should roll straight
• Lubrication - Use plenty of high quality graphite

We have several helpful pinewood derby books that give all the details on how to make your car fast.

My pinewood derby car is not going straight. What can I do?

First, make sure that you don't have a bad wheel. Spin each wheel with your finger. They should all spin about the same amount of time. Replace any wheel that doesn't spin very long. Next, check that the axles were inserted straight into the slot and are not at an angle. The next step is to check that your axles are straight. Remove the axles from the car. Insert each axle in a drill and spin it. The axle should not wobble. Replace any axles that wobble.  If your axles and wheels are good then the slots on your car block may not have been cut straight. Check that the slots are perpendicular to the car body. If the above steps don't solve the problem, you will need to bend the two front axles about 2 degrees right where they come out of the block. You can bend the axles by mounting them in a vice and lightly tap the axle our you can use our Axle Bending Tool or Rail Rider Tool to bend the axles.

My pinewood derby car wobbles.

Wobble will slow the car down and could cause the car to jump off of the track. There are several causes of wobble:

• Bad wheel - Spin the wheels. Replace any wheel that wobbles or doesn't spin as long as the rest.
• Modified wheels - Wobble can happen if the tread area of the wheel has been cut so that only the center part of the wheel touches the track.
• Poor wheel alignment - Roll the car on a flat surface. It should roll straight to within 6" after a 8' run.
• Center of gravity is too far back -The center of gravity of the car should be no closer than 1" in front of the rear axle.

Why is a heavier pinewood derby car faster?

Pinewood derby cars are powered by gravity. They start on a slope and the weight of the car pushes the car down the slope.  A heavy car will get more push as it goes down the slope.

What type of glue should I use on my Pinewood Derby car?

Use super glue on the accessories such as roll bars, drivers, spoilers and so on. You don't want those falling off!  Only a small amount of super glue is needed to attach these parts to your car. Make sure that the paint has completely dried.

Use a weaker glue on the axles so that you can take them off if you need to make a repair or adjustment. Most wood glues will work fine for this. To glue the axles to your car, first insert the axles (with wheels) in the slots and check for alignment. When all looks good, turn the car over and apply a small amount of glue near the end of the axle. It is important that you do not get any glue near the wheels. Glue is usually not needed if you are using holes instead of slots.

More about our glues

What is the best design for the front of the car?

A narrow front may cause a delay in the time triggering at the end of the track so the front of the car should be flat and at least 1/2 inch wide. There was an advantage to raising the front of the car but that is no longer the case with spring loaded starting gates.

Weights

What does a pinewood derby car weigh? What is the pinewood derby weight limit?

Most race rules limit the weight to 5 oz. For the most speed, your car should weigh as close to the limit as possible. If your race rules don't specify a maximum weight then the optimum weight is 9 to 11 oz depending on the type of wheels and axles that you are using and the type of lubricant.

What weights are best to use on my car?

We offer a wide variety of weights:

• Our stick-on and bottom weights break off into sections for exact weight adjustments.
• The cylinder and wire weights can be attached to your car by drilling holes and inserting in the holes then seal with glue or wood putty.
• The dome and triangle weights can be glued to the top of the car.
• The cube weights can be placed in cut-out areas of the car.

  We also have tungsten putty, adjustable weights and weights designed to be attached to the bottom of your car.

More about our weights for pinewood derby cars

What can I use to fine tune the weight of my car?

You can insert small nails in the back of the car (drill a pilot hole for each nail to prevent the block from cracking) but make sure that the nails do not stick out of the back of the pinewood derby car. They could cause the car to exceed the 7 inch limit. You could also drill a hole and insert bee bees in the hole then finish the hole with wood putty.

Where to add weight on a pinewood derby car? Where should I put weight on a pinewood derby car?

Usually, weights should be added as far back on the car as possible. When the car is completed, it should balance about 1" in front of the rear axle. To check the balance point, put a pencil across the bottom of the completed car and slide it forward or back until the car balances.

Track

How long and wide is a pinewood derby track?

Track dimensions can vary slightly but a typical track lane is 3.5" wide with a 1 5/8" center guide rail. The guide rail is 1/4" high.

Most tracks for official races are 35 to 45' long.  The start of the track is typically 45" to 50" above the floor.

We have economical track that can be used to test your car or hold your own races. More about our pinewood derby track

Should I build my car differently if it will be racing on an uneven or rough track?

To minimize the chance that your car could bounce off of a rough track, insert the weights in the car so that the center of gravity is two inches in front of the rear axle. Your car will be slightly slower but it will be more stable.

Miscellaneous Questions

What month are pinewood derby races held?

Most pinewood derby pack races take place in January though March. Winners in the pack races advance to the district races which typically take place the following April through June.

What should I do to my car just before the race?

Bring a small clean rag to the race with you. Before turning your car in, make sure that the wheels still spin freely then use the rag to wipe off the wheels making sure that the tread area is clean.

Is it better to put weight on top or bottom of pinewood derby car?

How do you optimize a pinewood derby car?

Which wheel should be raised on pinewood derby car?