Anyone have any Pinewood Derby tips/tricks?

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jeryst

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My son and I are working on his Pinewood Derby car for Boy Scouts.

We do it together, and its fun, but this is his third year, and he always loses. Of course, you know how it is. Some of the dads are really competitive, and they take everything to the extreme just to win.

So anyways, I've decided to fight fire with fire, and I figure since I have some of the best and most devious minds (FABO) available to me (Muahaha), I'd like to find out if any of you know some tips or tricks to make our car faster.

For any of you that dont know about Pinewood Derby, they basically give you a rectangular block of pine wood, 4 nails, and 4 plastic wheels. You can shape the car however you want, but it must come in under a certain weight, and you can not use any bearings or anything like that. The only lubricant you can use is dry graphite.
 
when i was in the scouts, my dad would help me with the weights, he told me to put them towards the front,make the car as heavy as allowed. he also sanded the wheels to round off the tread (for less of a contact patch on the track)make sure when you put your wheels on that they are perfectly aligned. we used the dry graphite on the axles. i wouldnt worry about making it aerodynamic as they dont go that fast. one other thing i would do is take alot of time and put a cool paintjob on it. they usually have a trophy for best paint also.
 
Sand the lettering off from the sidewalls of wheels, they cause friction when rubbed on sides of the track.

Its very tuff to get those four axel nails installed in a parallel plane, I'm not sure about the rules but is it possible to add a couple solid axels,drilled through and installed in a slightly larger hole, so as the axels spin independant of the wheels.
Lube the car at the body/wheel friction point. Do not paint the car on the small semicircle point where the wheels meet up with the body . Rather, sand this point to a smooth finish with a very fine sandpaper. Next, after masking off the body’s paint, gently massage some dry graphite into the wood. This will reduce friction and increase wheel speed.
Spend a fair amount of time on axle prep. Using a file and fine sandpaper, make sure you remove any burrs and defects from the axles, near the head of the nail. Some people will put a number of axles in a power drill and spin them to find the axles that are most straight (and eliminate any with noticeable wobble).



Acquire an accurate digital scale (such as the local coke dealer uses) build car with narrow profile,drill holes and add lead fishing weights as needed to bring back to desired weight.
 
Put the weight as far behind the rear axel as possible, if you are looking to be legal (as you should be in a cub scout event) no rounding of the tires or wheels is allowed, total length is measured, total width, and as was stated align the weight on each wheel by sitting it on a very flat surface and gently pushing down on each corner of the car to feel for even loading, some say they are faster with the most weight on two wheels by installing the axels slightly lower into the body, My experience was evenly loaded was fastest. There are more tip's in the pinewood grand Prix rule/handbook and yea give it a decent coat of paint. as a sponsor/official I'd say get the official rulebook and don't bend the rules....winning isn't everything when rules are broken to do so. We made trophy's from vacume advance covers and spark plug's, (all participants were given a hot wheel's car) invited a local highway patrol officer to be the judge of who won the races, and got a local pizzaria to host the event(they went over and above) and gave out gift certificates and a decent discount for those in attendance

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The fastest cars we ever built had axles and tires that I purchased online. We
reused them from year to year. You can find loads of tricks online.
 
they must have new rules since i was a kid. i would take waggins advice over mine if i were you.
 
My Dad and I bent lead solder into the shape of headers, looked cool and added weight. Used the graphite lube on the axels. But I dropped my car in the dirt before the race. Story of my life, lol.
 
Wagin, I never seen a track that was at a complete angle, all the BSA tracks I see have a starting ramp that is about a 1/3 of the track and then runs flat the other 2/3rds


Each district has their own rules as well as each pack, how ever if you get lucky and go further than district, their rules may be stricter and any mods like tapering the tires, using non BSA wheels and axles or shaving the BSA off of the tires will get you disqualified.

I always showed my son what to do and told him he will only do as good as the effort he puts into it, I never liked it when the fathers built the cars. I cut it out for him and re-drilled the axle holes but that is about where my help stopped. It paid off in the long run, he took first in his pack 2 years in a row out of 50+ cars. This was his last year and he didn't put as much effort into it this year so he didn't do as well, I was pretty pleased that he didn't take first again this year because it showed him the effort makes the difference, and I really didn't want to go to district again. You have to sit there all day while they race 500 cars, once you see a couple races, it all looks the same.

The wheels and axles make the difference, the few things I showed my son to do was chuck the wheels in the drill press with a wheel arbor so he could true them up with 400 grit paper, then chuck the axles in the press and use a small fine file to clean all the mold lines up and put a slight cone to the head of the nail and finish them off with 400-600 paper but don't polish to a shine though, the scratches from the paper gives the graphite something to hang onto. Then he put graphite in the wheels and chucked the wheels with the axles in the press and worked the graphite into them.

The weight should be about 70/30 over the rear axle, you want just enough weight in front of the rear axle to keep the front from coming up at the bottom of the ramp, the further to the rear of the car gives gravity more time to push the car down the starting ramp, if it is to the front, the weight pulls the car down the track and will stop pulling once the front of the car gets to the bottom of the ramp.

They also sell an axle jig to re-drill the axle holes, if you lengthen the wheel base as long as you can get it, it helps the car go straight down the track and keeps it from fish tailing, just make sure the overall length isn't too long. Some districts have different rules so he did have to cut a slot in the middle of the bottom of the car so you can see the ends of the axles but that was easy with a dremil.
 
The guy who won this years Derby...er blew away everyone else, showed me his trick. I'm going to try next year.

All of the previous ideas posted are correct and will work. The alignment is critical though. Using the notches already cut into the bottom of the kit cars will guarantee your car to be slow.

The trick is to flip the car over so the slots are on top and then re-drill the axle holes using a very precise drill or mill set up into the new bottom sides. That insures the holes are straight and parallel.

Combine straight and parallel axles with all of the other ideas listed on this thread and you are sure to have a class winner.......GOOD LUCK.
 
When I was in scouts I did the pinewood derby twice. I don't know if this is legal anymore, but we cut the part of the car out of the block that was going to be for the front axles. I'm not sure now if we redrilled the axle holes or not, but then ran a very small bolt and nut through this block through the top of the car. This allowed us to bolt this block of wood back up to the car and then "align" it so that it went straight. I would run it across the floor, see which way it turned, and then adjust as needed.

We did this alignment trick both years and never got in trouble for it. We did get disqualified the first year (they let us keep the trophy for winning, but didn't let us move on to the next level) because we sanded the tires down to narrow little points. The car was wicked fast.
 
Always check those nails they supply as axles for flash and any friction points.
 
Damn!!! no wonder my car was so slow-- we copied the picture on the front of the kit & slapped it together--- --had no idea!!
 
Install one of the rear wheels higher in the car body. The car will roll on 3 instead of 4 wheels and reduce your rolling resistance by 25%. Also, if your track has pegs for starters, you can shape the underside of the car from the nose to the front axles with a radius so that your car moves forward before the other ones do. You will get a jump and the other cars won't catch up. As the starter pin or dowel folds down, the car moves foreward because of the radius under the nose. This car was designed and built by my oldest son for the "sibling race". He won that race, best engineered, and fastest overall. It is painted with Duplicolor Mirage that looks like DuPont Chromalusion. Mike

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I believe that to be legal, you must use the original axle location, no flipping of the body top to bottom is allowed. No altered wheel base is allowed either.

If you have the opportunity to do a test run, try running the car backward as well as forward. This year my sons car ran much faster when put on the track backward. He took 1st place in his age group.

Aerodynamics do play a part, even is cars this small. Thin, sleek, heavy cars (at the 5 oz limit) will be faster than a tall blocky car.

Make sure the wheels do not touch the body when the car is sitting on its wheels. When you get them in a good spot, put wood glue in the axle grooves to keep them from moving.
 
In the spirit of competition, don't look to the grey area's of the rules, this ain't oval track racin, it's about teachin the kid's right from wrong as well as teachin them how to build stuff. If I had official rules to post I would do so and will try to get a copy of them to post. We had a limited amount of space and without knocking down a wall we couldn't run all four sections of track and other than renting a place we ran the race with three sections of track. all participants recieved a trophy and a hot wheel's car and all of the little kids that attended recieved a hot wheel's car also.There were a few cars that did not pass tech and we either helped them fix the car or allowed them to fix the car before the races were started...but did so in the spirit of not leaving anyone out.....Hope I worded that right and hope the way we handled it was acceptable.as was shown in the pic's a triple beam balance was used to check for legal weight and a bsa tech go-no-go gauge was used to check lenghth, width, etc.
 
69swinger340391 said:
I believe that to be legal, you must use the original axle location, no flipping of the body top to bottom is allowed. No altered wheel base is allowed either.


Make sure the wheels do not touch the body when the car is sitting on its wheels.
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The BSA rules do allow you to relocate the axle holes as well as several other mods but, your local district or pack may not allow them.

My son worked the graphite between the body and the wheels because the wheels will move back and forth on the axle and tap the body as it goes down the track, the graphite helps it from slowing the car down some.
 
You are right, it is our pack that does not allow alter wheel bases.

As far as the wheels touching the body, I should clarify and say that it is the top of the wheel is what should not touch, like a negative camber set up. the axle hub area will touch, and the graphite makes a world of difference here.
 
I helped my son win the cub scout troop pinewood derby three years in a row and latter helped my nephew win twice.

I would take the nails they require you to use for axles and spin them in a drill and file off any burrs under the heads and make the raduis from the head to the shank as tight as possible. I would spin the tires on an axle to make sure they ran true and would file the edges to remove any flash. I would also chamfer the center hole on the wheels on boths sides. The minimize the side to side slope when installing the wheels and use dry graphite as the lube for the axles.

The addtional weight to get to 5 oz's was installed into the bottom of the car flush and midway between the axles.

Paint general shape and stickers was left to the kids.
 
Burntorange70 said:
Put a Hemi in it!
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I was wondering when someone would say that - lol

Thanks for all of the great tips. I certainly dont want to break any rules, I just want him to win at least one race.

Our pack has quite a nice setup. They use double elimination so everyone gets a couple of chances to run. The track has a flat starting gate, and a sensor and timer at the end determine the winner and times. Amazing how some of the cars lose by just a hundredth of a second.

Keep the suggestions coming. The race isnt until March 20th. I'll post a pic of the car when it is all done.
 
One trick my dad and I always used was to carve a notch for the weight out of the bottom of the car, about 3/4 of the way towards the back, stick the weight in, and then use modeler's putty to smooth it over. I have no idea how the weight is attached now, being that its been a dozen years or so since I was in cub scouts. Don't put anything that sticks up on the car either, believe it or not there is still some aero that comes into play at this scale.
One of the fastest cars we made was a Viper GTS coupe, almost perfectly carved, and never beaten. But then we built a '69 Daytona (used plastic model sheet for the wing)...and put an estes model rocket engine in it (started with A size, ended with D size)...that one never touched the track and still won by miles haha. I know they're kicking around the garage somewhere....
 
chuck up those axles in a leath and cut a notch in it so the wheel only rides on a small surface of the axle.
 
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