Ultimate Guide: How to Build a Winning Pinewood Derby Car
Many people have asked me where to start on how to Build a Winning Pinewood Derby Car. So, I ask a few questions and spit out the answer based on those questions. I have taken some time to write down my racing theory based on a whole lot of hands-on derby time. More than most generations of builders have ever seen! Sure, grandpa might have build 20 or so cars, but I have built thousands, have my own track, and YouTube most of the builds. Definitions are at the end so if you see a term you don’t understand, check there for clarification.
My advice is usually a running tally of a few things. However, we have to know a few facts, and then we can work on helping you build that champion racer with your cubber. I know I can build a winner – so let me help you build your winner! First, you must know your track. Then, you must know your rules. There is a fastest possible build based on the info from those two questions. Below is my checklist that I go over with every fellow racer.
Build Check List:
- Type of track? Wood / Metal (determines proper COG, type of wheel also comes into play)
- Center rail present on your track? (determines type of steer)
- Can you camber your wheels? (can you use bent axles?)
- Do you have to run on 3 or 4 wheels?
- Type of lube? (will determine level of polish need for axles)
- Can you use weight reduced wheels? (needs to match track conditions)
- Does your budget allow use of tungsten weights? (last upgrade)
Racing Theory – Straight Shooter vs Rail Rider™
If you are like most, you’ve read so much information on the internet about how to build a winning pinewood derby car. If you are not building them every week of the year, a lot of the advice & tooling needed to make these builds aren’t items that most folks have in their toolbox. I will do my best to give you the proper advice on how to build the best pinewood derby car for your race based on your pack’s track. This is a combination of personal experience and evidence-based data presented over years of pinewood derby racing enthusiasts.
There is out there, a pretty prominent builder site claiming that a “straight running” derby car is the fastest. I 100% disagree with this simply because the track you will race on is put up and taken down every year by someone who is trying to do it as quickly and as efficiently as possible. A race track that never moves and maintained in perfect conditions will have different results. His suggested setup is fastest for his track conditions. His reasoning was also that the way the hub rubbed against the car body slowed cars down.
He also claims his wheels, axles, and car body weigh 11 grams prior to weight placement. Pretty impressive feat, I must add. Read below on my theory behind ultralight wheels and rail riding. 1 gram wheels are not necessarily the fastest wheel for every track.
Rail Riding for the win
As Derby Worx© has proven, rail riding is the fastest setup to build a winning pinewood derby car. Rear wheels will push away from the car body. When you rail ride, the steer wheel initially rubs the car body because of positive camber. However once the car steers in to the rail, the wheel is no longer touching the car body. The rest of the 40 ft+ of travel, the center rail is pushing against the inner edge of the wheel, which forces the wheel against the axle head, thus the wheel NEVER touches the car body again. Rear wheels with negative camber, never touch the car body. When done correctly, you only have 1 wheel riding against the rail.
Type of Build? Fun or Fast
Next question: are you building a league car or are you building a scout car? Sadly the biggest trophies are given to the fastest cars and thus, this has gotten us where we are today. The faster, the better…the more specialized, the better…higher polish axles, lighter weight wheels, laser cut bodies and other expensive alternatives. Whatever it takes to win!
As there is nothing wrong with league racing, the once-a-year builder does not understand all the build techniques nor do they know the terminology used for racing. They do not have the specialized tooling, nor do they realize these league racers build sometimes 100 cars to race in just one race. They try to accomplish the same tasks in 24 hours that these guys take weeks or months of preparation to obtain. Building a winning pinewood derby car is not an overnight internet read. Those that plan, usually come out on top.
Scout cars are just that. Novelty fun cars that have their unique flair that makes them builds that we all know are done from the scout. We love these builds. Love everything about them. This is what pinewood derby is supposed to be about! This is what we would like to see the niche come back to full circle.
Derby Dust has decided that it will focus the 2019-2020 season by going back to the foundation of pinewood derby. We would like to go Back to Basics (B2B). Our focus on new products will be at the entry/beginner level. An affordable car kit that the average person can put together quickly in a 24 hour span, and yet still get a good car.
League cars are the 1/4″ thick wafer bodies with aero fins, wheel dams, toothpick frame structures with monokote wrapping to remove all drag. There is nothing about them being that says it was a scout’s idea. Built for one thing. Top speed, low drag, max push. These things are so fragile that a entire dedicated stop section is needed to ensure to stop these fast moving bullets the safest possible way. And trust me…they are still moving crazy fast at the end of the track.
If you are building this car setup, you better be 100% sure your of track conditions, especially the stop track. If unsure on the stop track, I would opt for a little thicker wood around the axles to ensure it does not break off. Our B-Frame Body is a good starting point for this type of build.
The Setup…What does this mean?
First question you should know about how to build a pinewood derby car that wins is what track you are racing on. NASCAR changes the setup of their race cars for each track. Pinewood derby is the same way. If you don’t know, don’t be the guy that doesn’t ask for directions and then is lost for the rest of the trip. A simple email or text to your scout leader will get you the answer. Be prepared. Be a smart builder.
This is the most important first step in building a car. Don’t worry about the fastest parts, all that stuff just yet. What we need to know about the track will determine the entire build of your pinewood derby car. First is it wood, metal, plastic? Second is there a center guide strip that a car must race over? These two questions will determine a few other parts of your build later on such as Center of Gravity, and what type of tuning (steering) you are going to need to set up your car.
Setup is the foundation to creating a pinewood derby car that is first on the finish line. If your setup is correct, then the rest of the upgraded parts will ALWAYS give you an edge up. If your setup is wrong, adding upgrades will probably have ZERO benefit. You’ll see a lot of product reviews where there is a majority of 5 stars and then 1 stars with nothing in between. This simple data says it all…folks just didn’t get their setup right.
Wood Track Derby Cars
Wood Track- Since most adult league racers race on metal tracks, they tend to give out false info regarding wood tracks. Their knowledge is great, but their experience is limited. Wood tracks tend to be all over the place. They react to temperatures, they expand, contract, twist, warp, splinter, just about everything under the sun. These are the most unforgiving tracks. They usually have long ramps that let you get some really good speed at the very end of the race. Each section of the track must be carefully aligned otherwise you get bumps at every section. Bumps cause cars to fly off if the COG is not properly balanced.
A heavily weighted to the rear car might fair well on a metal or plastic track, but on a wood track normally tends to pop wheelies. Wheelies are what causes the cars to fly off tracks. Typically there are 4 sections to a track. 4 chances to get into trouble. It will be the utmost advantage that after you adjust drift (steer) run it on treadmill to ensure that the adjustments are true for high speeds. That little bit of wobble tends to become the death wobble. Once it starts, it doesn’t stop. Wobble plus bump = not fast car.
Wood Track Setups to Build a Winning Pinewood Derby Car
- Wood track with center strip, I suggest a COG of no less than 3/4 of an inch. Ideal is probably 1″ or maybe just a hair more. Keep the weight as close to the track as you can for the energy advantage, meaning as low as you can stack it on the wood body. 3 wheel center rail riding with camber wheels. Adjust your drift to 1″ on 4 feet of travel. Because the wood may splinter and no one really checks for this, I suggest a thicker or full factory rim wheel edge to ensure that the car will roll smoothly especially for the steer wheel. I believe that a thinned out edge will cause excessive friction and not allow the wheel to slide all the way down the track. So no wheel weights under 1.5 gram. Utilize the “stealth cut” design wheel where there is the full rounded factory edge if you are allowed to use a weight reduced wheel.
- Wood track WITHOUT center strip. These are just straight chutes for racing. Fastest cars will be straight shooters that never touch the bumpers. I suggest a COG of no less than 3/4 of an inch. Ideal is probably 1″ maybe just a hair more. Keep the weight as close to the track as you can for the energy advantage. Straight shooter…get that tuning board and adjust adjust adjust. Advantage here will be wheel weight. The lighter wheel you can use, the faster your champion racer will be which means the 1 gram wheels will give you the fastest runs. Camber all the wheels that are touching the ground. 3 wheel racer is preferred, adjusted so that you have no drift. No restrictions as this type of track you just pray you got a good line out of the gate.
Metal / Plastic Tracks
Metal / plastic tracks. This is where all the in and outs are written about. The majority of info about PWD found on the internet and in books is based on this type of track. There are a few brands of metal tracks out there, BestTrack is probably the most common. Most of the metal tracks contain a center guide strip for each lane. I have seen plastic tracks, but most of them do not contain a center guide strip. And that “test” track at the Scout Shop? Don’t even bother. Properly set up metal tracks give the most consistent data for PWD out there. A well maintained metal track is the best racing track as it will give the most consistent experimental data results. This is where all the data comes from that is given out on the league forums.
Wheel weights are a little fickle with a metal track. The lightest wheels are normally faster, but if you have too aggressive of a steer, the very thin wall of a 1 gram wheel causes excessive friction as it runs down the lanes. You can hear it as it races down the track. I have seen 1.5g wheels with thicker edges run consistently faster than the 1g wheels that are not “perfectly” tuned. My only conclusion was the excessive friction from the “knife edge” of the 1 gram wheel slowed it down. So if you are going 1 gram with a center rail? Spend the extra time to ensure that your drift is 3/4-1″ on 4 feet of travel which means you need at least a 5ft tuning board to test. Any more is probably going to slow things down a bit and take away the advantage.
Metal Track Setups to Build a Winning Pinewood Derby Car
- Metal track with center strip – I suggest a COG of no less than 1/2 of an inch. Ideal is probably 3/4″ maybe just a hair more. There are a few highly guarded secrets, this is one of them. So many different suggestions here. Again, know your track. Are the seams even and flush, and are there any burrs on the rail? Keep the weight as close to the track as you can for the energy advantage. 3 wheel center rail riding with camber wheels. Steering drift of 3/4-1″ on 4 feet of travel. I like to stack 2 oz of weight behind the rear axle for longest push.
- Metal / plastic tracks WITHOUT center strip. I suggest a COG of no less than 1/2 of an inch. Ideal is probably 3/4″ maybe just a hair more. Keep the weight as close to the track as you can for the energy advantage. Straight shooter… get that tuning board and adjust adjust adjust. The advantage here will be wheel weight and weight placement, even aerodynamic advantage if you have the time for some fenders. No restrictions as for this type of track, you just pray you got a good line out of the gate.
Build a Winning Pinewood Derby Car Parts: How to have an advantage
Assuming everyone has the perfect setup, has the perfect tune, has all the before mentioned variables the same, the following things are the core upgrades things that will give you an advantage over the next guy:
- Pine body with least amount of weight. This is simply done by removing as much weight as possible by design (wafer car) or by removing as much pulp as possible also known as resin, sap wood. Some blocks weigh more because they contain more sap. Best just to have a couple of blocks on hand to start with and use the lighter block. Some people even bake the block in the oven for a couple of hours to bleed off a few more grams of moisture. So yea that move Down and Derby people do go crazy with this stuff. We like the new 1/4″ wafer / ladder cars, but that is leaning more towards league car designs. If you have a hunk/chunk of wood, I would take a drill to the bottom and drill out as much wood as you can. Then cover the bottom with some foil tape from Home Depot or get a strip of it from us.
- Make sure your car is 7 inches in length. If you are short add the extra to the front to ensure the car is staged at the highest point for the most stored energy. Adding the missing to the back does nothing for your build.
- Make sure to design your car correctly. There is a correct front and back part of a block. The slot closest to the end is the back side of your car. Yes it does matter. If you can stretch your wheel base, an extended wheelbase usually has the advantage.
Straight axles… Even if you are going to bend them, very light file work ensures greatest axle diameter. Smaller diameters will cause wobble issues. To build a winning PWD car, straight axles are very important to start with prior to any bending. Double bends will drive you crazy. This is a great video on how to work axles if you are a DIY type guy.
- Polish levels: 3k for graphite, 100K for oil.
- Wet Sand metal to 2000 grit, then a final polish with a diamond paste.
- Never try to bend axles while in the pine block. YOU WILL BREAK the wood.
- If you are allowed to groove the axles, a good set of grooved axles always gives an advantage.
- If you can use aftermarket axles, I highly suggest looking at the Derby Worx line of machined over-sized axles for minimal wobble.
I have gone over how to choose the best wheels for your car based on track conditions. Ultimately your local pack rules will tell you what wheels you are allowed to race with. From there, we then chose the best wheel for your track. Not all packs are equal and all rules are different. Then choose your wheels based on what your pack rules allow and what type of track you are racing on.
- Click here to get a decision tree to determine what wheels are allowed for your pack.
Once you figure out what wheels you can use, my next advice is wheel prep. This is an important step in getting the most out of your wheel. Reducing the weight of the wheel helps it achieve faster results and so does wheel prep.
Polishing the inner bore is a step that most average BSA racers skip, and every league racer does. This alone tells you the importance. If you need to get the most out of your race, take the 30 mins to polish the bores. We offer a kit that contains all the bits and pieces to do a few wheel sets.
- True machined round wheels will give you an advantage
- Lightest wheels that you can use will give you an advantage
- Polished bores will give you an advantage
Hard Core racers will coat the inner bore with a fine layer of synthetic wax after the polishing step. As most cub racers are in a time constraint, we feel that polishing alone is adequate enough to give you the advantage over most. It can be accomplished in a 30 min span. If you are running in the Mid-America or NYC race tourney, you will definitely need to step it up a notch with a bore waxing. Derby Dust is working on an entire process for graphite wax prep. You’ll need a couple of days to prep as you need to allow the bore wax to cure to a hard finish prior to racing…. Give us a little time to ensure it is the proper finish.
Know your rules. The majority of rules that I have read address this specifically: graphite or oil. This will tell you 2 things, what lube you need and what polish level your axles need to be at. For oil, as high as you can go! For graphite 3000 grit is as high as you need. The analogy I normally use is try to write on glass with a pencil. Then with the same pencil, try and write on some raw metal. See which one the graphite likes better. This is the very reason you don’t use graphite with 100K axles.
The Right Graphite Does Matter
Graphite dry lubes. There are a few different theories out there. I will simply state facts. Moly is harder than Graphite. Pinewood derby is raced at temperatures of 70-80 F degrees. A pinewood derby car is a 5oz rolling application. A derby race is 3 seconds in length with a top speed of 20 mph at a car’s top speed.
Pure graphite with ZERO additives is the best graphite dry lube. Adding moly to the above parameters does not improve the lubricating properties for those racing conditions. All it does is increase the overall hardness of the lube. It also messes with graphite’s natural chemistry of stacking or building of layers.
Moly is a single layer lube. You can not build layers to shed between races. Moly is used when there is high heat & high pressure. A 3 second race with a 5oz rolling pinewood derby car NEVER reaches the needed parameters to get the benefit of the moly additive. I have done hundreds of hours of research this and I have visited many professionals in the industry of tribology.
The thresholds are just not present to require adding an additive to a pure graphite lube for pinewood derby. Just my opinion.
To Oil or Not to Oil
Oil builds will take a special wheel prep which is a highly guarded secret among league racers. What they do is build this perfect wax barrier on the inner bores so that the wheel does not absorb the oil. I am not an oil racer, so I have zero advice to give other than go forth and read forums.
- Oil lube = 100K axles, polish bores of wheels with wax
- Graphite dry lube = 3000 grit axles, pure graphite lube
Weight is weight. COG is COG. Tungsten can be faster than lead if applied properly. Just because you use tungsten doesn’t make your car faster, though. Key to all this is potential energy. The more stored energy, the longer you accelerate. The higher up from the ground you place weight, the more energy you have. On an angled ramp, the highest point is the rear of the car.
This is where tungsten comes into play. If you can stack more weight in the rear, you have more stored energy. HOWEVER there is give and take. You have to balance the weight as described as COG or center of gravity / mass. Tungsten is the last upgrade that I suggest to give you an advantage. With that said, if I want to build the fastest car, I use tungsten with 2 oz behind the rear axle.
I know this one is a little silly, but it really will matter. Show up early. Help put the track together. Bring some sandpaper and bucking blocks to make things smooth. Inspect the track. A good track inspection can be done in less than 15 minutes. Bring a mule car. Run it a few times. Check for burrs, splinters, spacing at all sections of the track. Check each lane to ensure that everything is smooth. Everything is in your favor.
Make sure you have a good stop track. Bring an old bed sheet just in case your stop track is not adequate. Your track by far could be your biggest opponent if it is not thoroughly inspected. You took hours to build your car. How much time did you spend making sure the track is good enough to race your champion on? And yes, it’s your job! Remember nobody gets paid for doing this.
- Check the center strips from transition to transition for spacing
- Check the sides of the center strip for burrs or uneven transitions. If the next section of track is offset incorrectly, then this will cause your car to steer incorrectly or even make you jump lanes or worse, fall off the track.
- Check the top of the track where the wheel rides. Makes sure there are no protrusions, metal dings, etc. You want a smooth racing surface all the way down.
- COG – Center of Gravity / mass balance point in which the car balances on an edged surface. The number is described as how far the balance point is in front of the rear axle. Do not mistaken this with the rear of the car. Measure from the rear axle towards the front.
- Camber – the adjustment of the amount of wheel tread is touching the track. No camber = wheel is evenly flat to the track
- Tune / Drift / Steer – the adjustment made that steers a car off center when a car free falls on its own weight down a flat surface. Key here is you can not push to measure this. Car has to do it on its own with gravity. Any push will skew results.
- Reduced Weight Wheels – wheels that have been machined with sole purpose of reducing the weight. The inner wall has been thinned. Most wheels are considered reduced weight when they fall below 2.4 grams in weight.
Now that you know how to setup your car, watch this video on how to build the car using current tools on the market along with proper tuning techniques as discussed above.
Thank you, and good luck on your race!