Now before anyone goes and gets their undies in a bunch, neither my daughter or I will run the cheater car in competition, I just want to see how much of a difference the parts really make.
Now that that's out of the way, where are the cheater parts sold and what's available these days? Special grease, special axls, magnetic weight? Powered wheels?
In short, what's the hot rod ticket for an outlaw racer?
My boys did pretty well in Pinewood Derby, but I don't think any of our mods were per se illegal. Obviously, you want as much weight as far back as possible, just be sure your car won't pull the front wheels off the track when it hits the flat portion. Polishing axles is important, and graphite for lube. Be sure alignment is good--car needs to track straight on a flat surface. I honestly don't know anything about cheater parts, but I know that attention to detail will make a fast car.
In reply to RevRico :
I know a guy who builds these for a living. Literally left a master-certified lead-tech job for Toyota to do it full time. He sells scout legal kits, fully built cars, and the same for other rulesets. Those guys are racing for .001ths.
The biggest things are wheels and axles for the high dollar stuff. For rules legal, precision in placing the axles, and attention to where the weight is placed fore/aft. Shape is mostly irrelevant.
Alignment is also crucial. YouTube has some good stuff, but the super competitive guys are bad gatekeepers.
To start, look up "three wheeling" "pinewood camber" and "riding the rail"
Most don't allow grease - graphite is okay.
A lot of time spinning the axles and polishing.
I've heard the 3-wheel thing too.
In reply to barefootcyborg5000 :
I noticed rail riding on one site I found. I don't remember it being legal when I was a cub, but that was 30 years ago.
I wonder if I could get a track, or equivalent, to use for home testing.
In reply to RevRico :
You can usually get the alignment close enough to ride the rail without a track. Something like 1" of turn in 3'. There's a formula but I forget.
weight should be rearward, CoG just ahead of the rear axle.
One front wheel just off the surface, all wheels slightly negative camber.
POLISH THOSE AXLES. And make sure the wheels are round and free of flashing or other blemishes.
All this is from memory. All this info is at least four years old.
You don't want grease, you want light weight secret oil. Speed is made by reducing friction between the wheel and axle and wind resistance. The cheater axles reduce surface area where it contacts the wheel. The good wheels are cut down to reduce weight and run true. Wheel alignment is very important so it runs straight down the track with the front wheel guiding it on the rail. The back axles are aligned to keep the wheels off the body. And one front wheel shouldn't be touching but just along for the ride. Weight should be as much in back as you can, then it is pushing you down the hill longer. It is fascinating the science and work that can be involved to go fast for a seemingly simple race. Derby Dad for Hire is one place that sells good stuff and there is a forum associated with it. Gravity(weight) is your engine, friction slows you down.
About 40 years ago my neighbors Dad would "help" his son with his derby car. They would cut the wheels down like this.
They would still have the wheel face showing. something in the rules about having to use the original wheels. They also used two straight tubes with the axle running through. Making both wheels rotate equally. And yes to the graphite. I dont remember if they won alot... and there wasnt much of the original piece of wood left. Something like this but was thinner.
I would disagree about using graphite. Oil is faster and lasts longer. With graphite the speeds tend to fall off. If you have to or want to use graphite, if you spray the axles with lemon pledge first it is supposed to be faster.
Do they pay any attention to the mass moment of inertia with the wheels? I remember seeing a comparison of wheel shapes that showed which ones would roll to the bottom of a hill the fastest, despite all being the same mass. Sphere was right in the middle, those big skateboard wheel shapes were near the top.
But just trimming them down as much as possible to minimize friction might trump all. Thinking out loud here.
I've always wanted to put so.ething like this on one and see what it would do.
There has never been an event that inspired so many armchair engineers.
I've helped build over 100 of these. Only 1 went to Regionals. I hope I never have to go there again. It was really kinda gross watching so many fathers acting like jerks.
I would enjoy having a separate unlimited event for fathers.
Im glad to see the OP is admitting these are cheats. Since we are cheating, the answer is shifting weights. Nothing makes as huge a difference (but they are totally not allowed).
Reducing friction, tracking straight, and alignment are all important. Oil, cutting wheels, substituting axles are also important (and all illegal).
The thing I've seen that seems to scrub the most speed is when the car bumps off the center guide repeatedly.
SV reX said:the answer is shifting weights.
This was my initial thought.
First to mind was some sort of lead ball in a chamber with a latch to release the ball to roll forward and give an initial "boost" to the start of the race. Maybe the latch release is when the wheels start spinning.
Never ran one, so I am completely keyboard engineering.
As long as we are cheating, consider springs and rubber bands.
In reply to preach :
I've never built one with shifting weights, but I know it's been done. I was thinking something that triggered at the bottom of the hill as the car changed from a 30* decline to level. Give a little kick on the flat.
Actually, that wasn't true. I did build a car once with moving weights. I embedded lead weights in the wheels to see if I could capture the rotational momentum (like a flywheel).
It didn't work. But I didn't try too hard. With proper machining it might.
I would enjoy having a separate unlimited event for fathers.
So our pack is super tiny. Like 20 kids, 10 adults. My daughter's den is 4 kids counting her. So they run an adult class at the pack meeting. I just haven't found out of its spec or open.
I did find out last night in my searches that a 2 lane track, with light tree, remote starts on each lane, and a few other things can be purchased and delivered for ~$1300. If I can convince enough of my friends and locals, might put together a beer league. Even the prebuilt rule busting cars are under $100, it could be a lot of cheap fun.
In reply to RevRico :
You'll need a 50' room to put it in! 
Part of the reason that there isn't really a science to this is that there are essentially no rules for building the track. I've seen them 32' long, but I've also seen them 50' long. Made of wood, plastic laminate, and aluminum. Steep ramp, shallow ramp. Differences in the size of the central guide block. Some 4' high, some over 6'.
Every car will perform differently on these different tracks. There are lots of rules about the cars, but almost none for the track.
And only 1 or 2 people have access to the track in advance.
I saw 1 track with a metal starting gate. A magnet in the nose of the car gave it a starting pull as the gate was released.
It's an event for 7 year olds.
When I went to Regionals, there were about 100 fathers in a pavilion fighting and arguing like they were betting on dog fights.
The kids were all outside playing on the playground.
I put on a derby for our local car show every year. Finally had to stop because the fathers caused all by volunteers to quit.
I see a lot of attention to the axles, what do people do with the thrust load on the outside axle? I presume the camber is in, which will push the wheel to the outside instead of dealing with the thrust load against wood.
In reply to alfadriver :
It is best if the wheel is riding on the nail head. You want to tilt the nail(axle) I think 3 degrees so that the wheel rides on the nail instead of the body. Polish the wheel and axle and oil/grapite where they make contact. The picture MyMiata shows this some but it's only a few degrees. Then the wheel is only contacting the track on the inside edge of the tire.
In reply to SV reX :
I used to help my dad run the one at his troop. It was fun to see all the overengineering, then to see all of it beaten by what looked like a broccoli crown hacked with a dull hatchet. There seemed to be little difference in most of the cars. One year I was out of time to make myself something, printed a bus on paper and glued it to an uncut block. It came in fourth.
In reply to BlindPirate :
So is the mail head polished like the rest of the mail? Is the wheel face modified to touch a specific part of the head?
In reply to alfadriver :
I messed with the nail head some, but it's tricky. If you change it's diameter or shape much, you risk it wedging into the hole in the wheel. That's not better.
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