Help with rules and how much I can do.

Hi, relatively new to car building, built a few with my Dad as a kid, but that was 40+ years ago and didn't have the technology and info available like today. I did a lot of reading, watching YouTube and ordered a lot of stuff last year and our Lion car was the fastest on every run (but didn't realize they were not giving trophies for fastest Lion car last year, lol). We are in a new pack this year because my son changed schools and are working on his Tiger car for the race a week from tomorrow. Before we started (are not too far long at this point, just general body shape) the only rules relayed to me were that we had to use all of the stuff in the box, no oil. Then I asked a couple questions and was told I could not drill new axle holes and had to use the slots, could not use colored wheels from the scout shop (must use the ones in the box). Then 2 days ago they sent out the "official rules" (nothing like waiting until everyone was into their build, but maybe not too many of us that are new this year). This is what they are saying, and my question out there to the veterans is can you take a look at this and let me know what you would recommend we do to stay within the rules but still build a fast car. Originally I has set out to drill the back axle holes at an angle, bend the front right axle so I could adjust to ride the rail (they use an aluminum track) and raise the other front so it wasn't touching. Not sure we can do any of that now. Thanks for any help/advice anyone can give. I have or have access to pretty much any tools and a lot of the popular jigs for PWD car building.

A few key notes:

1. You MUST use the pieces provided in the official kit--no substitutions allowed for wheels or axles!
2. You MUST use the factory-drilled axle slots
3. Cars may not exceed 5oz, but aim for exactly 5oz--if they weigh much less they will not cross the finish line (cars MUST cross in at least 1 heat to be eligible to compete for turtle).
4. Adults may HELP their scouts with this project, but the SCOUT should build the car. A new tradition at the AOL level: cars must be entirely boy built--parents may advise but may not assist in any way except to supervise and ensure safety.
5. No liquid lubricants allowed! Carbon graphite is an acceptable lubricant.
   
   
   
   

DESIGN AND CONSTRUCTION RULES

1. Race cars may weigh no more than five ounces (total weight) as measured

by the official scales at check-in.

2. The wheels and axles furnished with the kit must be used. The axles must

be placed in the factory cut grooves.

3. Race cars may be no longer than 7 inches, nor wider than 2-3/4 (2.75)

inches, with an underside clearance of at least 3/8 (0.375) inches and inside

wheel to wheel clearance of at least 1-3/4 (1.75) inches. Wheelbase is to be

5-3/8(5.375) inches.

4. Weight may be added to the car and will be considered part of the car for

purposes of all measurements. Weight must be nonmoving, solid, nonmagnetic, and must not effect clearance, length, or any other dimensional requirement.

5. Hub and tread smoothing and polishing may not result in substantial removal of mass or reduce the wheel width from the original kit wheels. Some of the original "tread marks" on the wheel face must remain intact, i.e. apparent to the inspector. Wheels may not be beveled and the wheel surface that touches the track must be parallel to the axle. (I ASSUMES THIS MEANS WE CAN"T ANGLE THE WHEELS SO THEY RIDE ON THE RIM OF THE WHEEL?)

6. The following may NOT be used in conjunction with the wheels or axles:

washers, inserts, sleeves, bearings springs or suspensions.

7. The race car may not be constructed or treated in such a way that the track's starting mechanism imparts momentum to the car. (Cars with sticky substances on the front of the car, protrusions, or magnets will be disqualified.)

8. Only dry lubricants such as graphite or powdered teflon "white lube" will be allowed for lubricating the wheels. Lubricants may not foul the track. Lubricant may not be added after the cars have been checked in.

9. Design competitions allow and encourage the use of accessories. Accessories must be non-movable and the car must meet all other rules.



Derby Made Easy! Suggestions for Making a Car:


Overall Design

1. Do not shorten the car. Make sure it is the full 7 inches long.

2. Leave the area at the axles the full 2-3/4 inches wide.

3. Have the rear axle be the one in the groove closest to the end. Do not move the axle

grooves.

4. Be sure the axle grooves are parallel to each other and perpendicular to the bottom

of the block.

5. Do not bring the front of the car to a narrow point. The front starts against a pin or dowel

and if it is too thin/small, the start will not work properly.

6. Aerodynamics have very little effect on the performance of the racer.

7. Cool designs are acceptable. A car does not have to look like a car to do well.

8. Trace the design on the block and then cut with a band, scroll, or coping saw under the

supervision of your parent. (Note: boys should practice on scrap wood first!)


Wheels and Axles

1. Use very fine sandpaper to remove any mold flash or plastic from wheels.

2. Do NOT make the wheels thinner, narrower, or change any part of the design.

3. Polish the axles until they are very smooth. Use a rag with jewelers rouge of various grits

or very very very fine sandpaper. Do not remove lots of metal, just get them smooth.

4. Have only three wheels touching the track. Raise a front one slightly.

5. Be sure the axles are parallel to each other and perpendicular to the length of the body.

6. After assembly, gently roll the car on a smooth floor and see if it rolls straight. If it

pulls to one side it may not track properly. Look for an axle that is not perpendicular.

7. Wax the wheels with furniture polish. Make sure the polish does not contain a solvent of

any sort. (remember that no residue can be left that might foul the track)

8. Do not set the axles at the top of the groove. Set them about halfway down for greater

track clearance.

9. At final assembly time, put a drop of glue inside the groove to hold the axle.


Lubrication

1. Use graphite or white lube only. Use only dry lubrication.

2. Spin the wheels and lube them repeatedly.

3. Just before the car is checked in, re-lubricate the wheels.

4. A small amount of glue placed where the wheel meets the body of the car will provide

a hard surface for the wheel to spin against. Be sure to lubricate this area.

5. Before mounting the wheels, rub graphite on the axles.


Weight

1. The car should weigh close to 5 oz as possible, without going over.

(use an accurate scale to weigh the car at home during assembly)

2. Different scales have different results. Be sure you can remove a little weight.

3. Be sure to keep the weight between the wheels. Some people believe that closer to

the rear tires is more effective.

4. Place the weight low on the car and centered left to right.

5. Avoid molten lead for weights.

6. If you add weight to the bottom of the car, be sure to inset it so it doesn't drag on the track.


Finishing and Accessories

1. Sanding the car is done in multiple steps. Start with coarse sandpaper (the lower numbers

like 60 or 100 grit) and move to successively finer grades. 400 grit will leave a very smooth finish.

2. Sanding is not real exciting, be sure to share that work. (a good place for adult help)

3. Prime and sand the car with fine sandpaper before final painting.

4. All paint works better with several thin coats rather than 1 thick coat.

5. Hard surface finishes will act as a slick surface for the wheels to rub against.

6. Weight your car with the accessories you plan to use before assembly. It’s tough to

remove the head of the driver to make weight! (use an accurate scale)

7. Be sure to seat all accessories and glue or screw them in place. A drop of glue will not

hold them together on race day.

8. The car may be placed upside down during race day, plan your accessories accordingly.

 

Is this a BSA kit? The wheel base should be 4 3/8" not 5 3/8"...
You should
Pledge your axles.....after you remove head spurs, polish lightly with multiple grades of wet sanding papers 800-3000
Mix graphite into the glue near all your body hole for axles and polish
Rail run for sure
Dont forget to burnish your wheel bores with graphite
Pin the raised wheel tight so it doest spin....only needs to be raised a little nothing crazy maybe 1/8"
Drill the slot locations canted at 3 degrees with your jig
Clean all the burrs and flash off your wheels
And any or good recommendations from the awesome guys here

 

Get extra kits & select the roundest wheels & straightest axles.
I feel like the axles need to be as far up the slot as you can get them to lower the body & weight.
You can narrow the front the width of the hub & you will still have 1 3/4" between the wheels , but that's quite the set of rules so you may not want to test them at inspection.
Burnish the inside & outer hubs, even the wheel edge while your dealing with the bores.

Good Luck

 

Thanks for the advice, I was worried I would be going against the rules if I drilled angled holes for the axles and a new hole for the raised wheel?

First time I have heard of pinning the raised wheel so it can't spin, that is interesting. You lost me with the "Mix graphite into the glue near all your body hole for axles and polish", are you talking about where the wheel meets the body at the axle? I was going to put some clear fingernail polish and then coat with graphite, is mixing graphite in with glue better? (like super glue I assume?).

I ordered the black ice and zero friction kits, but not sure they will get here in time. I have some stuff from last year to use on the wheels and axles if not.

I spent a lot of time last year using the MV Wheel Shaver, but not sure that was really necessary compared to just lightly sanding the wheels while they are spun in the drill press? After reading more this year I think I probably sanded my axles and polished the bores in the wheels too much last year and created too much play, I will work on not doing that this year but still getting them totally smooth.

I have a 2.5 degree axle jig, I will order the silver bullet for next year.

Thanks again

 

Also forgot to answer, yes my kit is 4-3/8" wheelbase, they said those rules were from 2004, I guess they changed the kits at some point but not the rules they are using?

this is the kit we are using;

 

Thanks

I bought a bunch of extra kits and wheels from the scout store last year, I will go through them and check to make sure they look exactly like the ones in the kit we received from the pack and then select the best wheels. What is the best way to check the axles and wheels to select the best ones?

 

On wheels you want to check the runout (less is better) and size of the bore hole (smaller is better), and even the weight (lighter is better). The best way to check the runout is with a dial indicator if you have one. For the bore hole the best way to measure are a set of pin gauges of various sizes, .095 to .098 should do it. However, if you don't have that you can use Kroger (you're in OH) brand Qtip (cotton swabs) stalks to check the bore, make sure they are the ones with the paper stalks. They are very close to the bore size of the wheels. You'll want to choose the wheels that are tightest on the swab stalk. You can also use the swab stalks to polish and prep the wheel bores. You'll also want to spin the wheels, preferably on a pin gauge, but the axles will work if that's all you have. You want to see how the wheel spins, less wobble is better.

On axles you want the ones that are straightest, and the biggest around. Spin them in a drill and use a set of calipers to figure these things out.

Good luck!

 

Thanks, will do all of that. I have everything but pin gauges in that size, I will pick up a set though.

 

In addition to the Advice you’ve already received you should buy a vintage kit from ebay. You’ll find the older kits have larger axles. I’d bet the axles you have now measure .088-.089”. The older kits have axles that measure .091-.093”

 

By rule #1 it looks as if you cannot use any other wheels or axles, unless it's from the current kits that are being sold to you.

 

Hey Jason, I initially thought the same thing but he mentioned he was using other kits for wheels so I thought he’d be okay. Remember, those are official kits and it didn’t specify what year.

 

Don't you mean those were official kits?

 

... Mike, yes you are right. They are official BSA kits from the year 1985.

 

Yes you are right Jay.

 

Yes. I was told all axles before 89 were that large.

 

Ummmm I just wanna race.......

 

Me to chuck. It kinda sucks the two leagues I race took off January

 

John's race is coming up.......

 

Now is the time. Register. Oil. Send. I should be there in BASX and Unlimited. And Maybe MA.....But I need to prep to ship.

 

When is the race? I haven’t touched my cars since the npwdrl finals