My son's pack adopted new rules which allow a raised 4th wheel but don't allow cant/camber. They require the full width of the wheel to touch the track. I assume that we can angle the DFW forward to create toe in and keep all the tread touching. Is there any guidance as to how many degrees we would need?
rail riding without camber
- Thread starter Vettehog
- Start date
With the DFW requirement to be flat will require you to drill the DFW hole without a cant, but drill it with toe of about 1.4 degrees. That might be overkill, but it's safe for crazy rules. Another alternative to these tough restrictions and still rail ride is to drill the REAR DFW forward inrelation to the REAR NDFW so the thrust angle is pointing to the left if you want to steer to the left. Usually 1/32 forward is good to steer the car to the left. So if you drill your REAR NDFW at 20/32 from the rear then the REAR DFW should be drilled at 21/32 from the rear edge. It's always some crazy rules that drive you nuts. I would still shave off a little on the front DFW side so the rear wheel does not touch the rail. I would think 1/32 shaved off would not be noticeable to the rules committee.
If you hammer the nails in the slots you will have cars with bent axles, canted axles, running on 2 wheels, 3 wheels, 4 wheels, stopping on track, etc. If you drill your holes and the drill table is not perfectly square they are not going to be the perfectly level axles the rules make it seem are required. So if you interpret your rules to mean no obvious canted axles and the wheels just need to sit flat you can cant a bit. I believe 1 degree may be a consensus amount that will allow the wheels to sit flat. You could even say for the front axle if it is straight where it goes in the body but bent allowing it to steer a little and still sit flat you would be legal.
If the rules are written like I think they are and are strictly enforced there could be a lot of disappointed people come check in.
Post your complete rules and you will get excellent feedback on what a good build would be and still be within the rules or intent of the rules.
If the rules are written like I think they are and are strictly enforced there could be a lot of disappointed people come check in.
Post your complete rules and you will get excellent feedback on what a good build would be and still be within the rules or intent of the rules.
Thanks for all of the replies. Below are the official rules.
1. Each entry shall be constructed from an up-to-date B.S.A. Pinewood Derby Car Kit for the current year. A new car
must be built for each year. All nine pieces must be used. The car must be free rolling. No starting devices are allowed.
2. Overall dimensions (length & width) - Place car inside a checking device, which is 2 & 3/4 inches wide by 7 inches long.
The car must not be greater than 2 & 3/4 inches wide (including wheels) by 7 inches long (including accessories). The original Pinewood body (NO PLASTIC/FIBERGLASS OR METAL CARS) of the car must touch the starting gate (pin). No part of the car can extend in front of the starting gate (pin). Again, be advised, no plastic/fiberglass or metal cars will be permitted.
3. Wheel Base - Place car over a checking device, which is 1 & 3/4 inches wide by 7 inches long by 3/8 inches high. The
Distance (width) between the wheels (front or rear) must not be less than 1 & 3/4 inches (measured from innermost part of the wheels). The distance between the track and any part of the underside of the car must not be less than 3/8 of an inch. Wheels cannot extend in front or rear of the body of the car. All cars must have ( 4 wheels no more no less ) and are required to have 2 wheels on each side opposing each other. NO OFFSET WHEELS.
4. Visual Inspection of the Wheels - Wheels and axles MUST be the ones furnished in the car kit. Solid axles are not
permitted. Replacement wheels and axles must be from an official BSA kit. Axles may be polished and lubricated (dry lubricant only). Wheels may be sanded to provide a true round circle but must retain the original width and flat rolling surface. No purposely-rounded wheels allowed. No "H" or "A" wheels. No attachments or adhesives will be allowed on the surfaces of a wheel. Wheels will be placed on a flat surface to verify that the entire width of at least three wheels make simultaneous contact with the flat surface while stationary and in travel. (NO ANGLING OR CANTING OF THE WHEELS) Regardless of what they could be made out of, spacer bearings, washers, bushings or springs are prohibited, whether fixed or movable.
No car will be allowed to enter with a closed hub or totally enclosed axle (nail on wheel). Axles will need to be secured in pre-cut slots with clear glue (if glue is used) or if the axles are inserted in holes in the side of the car, then removed by the Cub Scout and parent (guardian) to verify that axles are not solid. Holes may be drilled in the bottom of the car so the points of axles (nails) can be seen. Axle (nail) points must be in view before a Cub Scout can enter the race.
5. Weight - Entry will not exceed 5.0 ounces or 141.745 grams. Weight must be securely fixed to the car and non-movable.
1. Each entry shall be constructed from an up-to-date B.S.A. Pinewood Derby Car Kit for the current year. A new car
must be built for each year. All nine pieces must be used. The car must be free rolling. No starting devices are allowed.
2. Overall dimensions (length & width) - Place car inside a checking device, which is 2 & 3/4 inches wide by 7 inches long.
The car must not be greater than 2 & 3/4 inches wide (including wheels) by 7 inches long (including accessories). The original Pinewood body (NO PLASTIC/FIBERGLASS OR METAL CARS) of the car must touch the starting gate (pin). No part of the car can extend in front of the starting gate (pin). Again, be advised, no plastic/fiberglass or metal cars will be permitted.
3. Wheel Base - Place car over a checking device, which is 1 & 3/4 inches wide by 7 inches long by 3/8 inches high. The
Distance (width) between the wheels (front or rear) must not be less than 1 & 3/4 inches (measured from innermost part of the wheels). The distance between the track and any part of the underside of the car must not be less than 3/8 of an inch. Wheels cannot extend in front or rear of the body of the car. All cars must have ( 4 wheels no more no less ) and are required to have 2 wheels on each side opposing each other. NO OFFSET WHEELS.
4. Visual Inspection of the Wheels - Wheels and axles MUST be the ones furnished in the car kit. Solid axles are not
permitted. Replacement wheels and axles must be from an official BSA kit. Axles may be polished and lubricated (dry lubricant only). Wheels may be sanded to provide a true round circle but must retain the original width and flat rolling surface. No purposely-rounded wheels allowed. No "H" or "A" wheels. No attachments or adhesives will be allowed on the surfaces of a wheel. Wheels will be placed on a flat surface to verify that the entire width of at least three wheels make simultaneous contact with the flat surface while stationary and in travel. (NO ANGLING OR CANTING OF THE WHEELS) Regardless of what they could be made out of, spacer bearings, washers, bushings or springs are prohibited, whether fixed or movable.
No car will be allowed to enter with a closed hub or totally enclosed axle (nail on wheel). Axles will need to be secured in pre-cut slots with clear glue (if glue is used) or if the axles are inserted in holes in the side of the car, then removed by the Cub Scout and parent (guardian) to verify that axles are not solid. Holes may be drilled in the bottom of the car so the points of axles (nails) can be seen. Axle (nail) points must be in view before a Cub Scout can enter the race.
5. Weight - Entry will not exceed 5.0 ounces or 141.745 grams. Weight must be securely fixed to the car and non-movable.
If you can get access to a drill press, get the Silver Bullet to drill your axle holes. Drilling the rear axle holes at a 1* cant will allow you so still follow the rules. You will need to use a different size pin then what is provided in the SB. In a pinch a smaller drill bit would work for a pin to set the angle. The tool comes with a chart that you can reference to find the correct size pin to get a 1* angle. Then you can drill access holes to see the tips during inspection. The access hole can also be used for tuning your DFW steer without having to cut a groove in the axle head if it is made just big enough to fit a needle nose pliers.
Even if you just use the original axle slots, most scouts will likely have some degree of angle in their axles even when trying to install them in perfectly straight. Purposely biasing your rear axle angle in the desired direction will give you a better chance to get the rear wheels to ride against the axle head.
It looks like your rules allow for extended wheel base. I would start with your rear axle 5/8" from the back of the car and your front axle position around 5" or more from the rear axle. Fully extended, I wouldn't put your front axle hole any closer to the edge then 7/8" so you have a little nose on the car to keep the wheels from hitting any bumpers in the stop section.
Even if you just use the original axle slots, most scouts will likely have some degree of angle in their axles even when trying to install them in perfectly straight. Purposely biasing your rear axle angle in the desired direction will give you a better chance to get the rear wheels to ride against the axle head.
It looks like your rules allow for extended wheel base. I would start with your rear axle 5/8" from the back of the car and your front axle position around 5" or more from the rear axle. Fully extended, I wouldn't put your front axle hole any closer to the edge then 7/8" so you have a little nose on the car to keep the wheels from hitting any bumpers in the stop section.
Those rules are not as bad as I expected. The wheels just need to be flat it does not say axles must be parallel. You can drill holes with inspection holes so you are covered there and do not have to use slots. Replacement wheels and axles must be from a BSA kit so you could get a set of Revel BSA wheels and use the better China made axles. It does not say graphite or Teflon lubricants only, just dry lubricant so depending on your interpretation you could have some flexibility there.
So you can do a lot, stay legal easily and have a fast car.
For our cars the Zero Friction Graphite Lube from Derbydad4hire maintains speed using the Pledge and Red Rocket. Our cars have run 12 times on it and maintained consistent speeds on all 12 runs. It did not slow down.
Good luck. You are at the right place to get information.
So you can do a lot, stay legal easily and have a fast car.
For our cars the Zero Friction Graphite Lube from Derbydad4hire maintains speed using the Pledge and Red Rocket. Our cars have run 12 times on it and maintained consistent speeds on all 12 runs. It did not slow down.
Good luck. You are at the right place to get information.
I love this time of year because I get to hear all the crazy rules people try to come up with to keep it "fair" and take away from kids imagination/learning science. Trying to get all the tread of wheels on the track with stock slots is tough. I had parents come in with cant'd wheels without trying or knowing they did it. I wish people that made these rules would do research first and not limit kids to being being slow.
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