Certified Safe Site
Jun 19 2024
Pinewood Derby on Facebook
pinewood derby

Adding Tungsten Rods to bring a Pinewood Derby car up to the 5 oz limit 

Example of pinewood car


How to add Tungsten Rods to a Pinewood Derby Car

Tungsten Rods

These 9/32" diameter rods are ideal for low profile blocks where the tungsten cylinders won't fit.. 

Sold in sets of three 9/32" diameter rods. Each rod weighs 1/3 oz and is 9/16" long.
Total weight of the 3 rod set is 1 oz.
Typically you will need two to three ounces of weight to bring your car up to the 5 oz limit. These rods work best in combination with other weights such as the domed and bottom weights.

Before adding the weights to your car, put the car block, wheels, axles, weights and any other accessories that you will be adding to your car on a scale. Then add the rods until the total is 5 oz.

Below are a few techniques for adding tungsten rods to your pinewood derby car.

You will need:

  1. Two or more sets of Tungsten Rod Weights
  2. 1/8" and 5/16" drill bits.
  3. Tungsten putty to fine tune your car's weight.
  4. Wood putty.
  5. Sandpaper

Blocks that are at least 1/2" high

Adding weights to a low profile pinewood derby car.
  1. Drill four holes in the rear of the car with a 1/8" drill bit the following distance from the side of the car: 1/4", 11/16", 1 1/6", 1 1/2". Drill the holes again with the 5/16" bit. Drilling the small holes first will make it easier to place the holes and keep the large bit from drifting. The holes should be deep enough for one tungsten rod plus any tungsten putty that you are using. Do not drill into the rear axle slot.
  2. To add additional rods, drill holes in the side of the block in front of the rear axle as described below.

You can also drill from the side

Insert weights from the side of the car

Starting from the rear of the car, drill as many holes as you need into the side of the car. Each hole can hold two weights plus some tungsten putty. The weight should be centered in the block so drill the holes 1 1/5" deep (deeper if you are adding tungsten putty.

Blocks that are at least 5/8" high

Install weights over the rear axle slot.

Drill four holes in the rear of the car in the same manner as described above but drill 1/4" from the top of the block. You can drill as deep as needed to hold all the the weights..

Final Steps

  1. With the weights in the blocks, weigh the block, wheels, axles and weights again. If the total weight is less than 5 oz, add additional Tungsten Putty.
  2. Seal the weight holes with the wood putty. Allow to dry in a warm place for 12 hours.
  3. Sand the wood putty until smooth and flush with the car block.

You can now paint your pinewood derby car and add the wheels and axles. 

Weigh your car one more time and add more weight if needed or drill wood from under the car if it is too heavy.