Which wheels to cant & which to keep straight

[rferrin]

I am looking to raise one front wheel and create a "rail rider" for the first time. I also want to cant the wheels using the silver bullet. My question is do I cant just the back two wheels or all three that will touch the track? If I do this how do I steer the car into the rail then? Or should I do the axle bending for the front wheel that touches so I can steer it into the track at the proper degree, if I do this I assume that you don't drill the cant hole for this wheel?

[resullivan]

You cant the back two and bend the front one.

[rferrin]

If I cant just the back and build a rail runner, will my rear wheels stay off the rail and track outward? If not is there a technique to make sure they track outward and off the rail?

[resullivan]

If the DFW is inside the back wheel then the back wheel should stay off the rail. The canting of the back wheels cause them to track to the nail head.

[Speedster]

rferrin, Welcome to Derby Talk.
You will want to narrow the wood 1/16 inch at the DFW (Dominant Front Wheel). Bend the axle 1 1/2 degrees and give the wheel POSITIVE Camber. Be sure to mark the head of the nail with a sharpie when you make the bend so you know where the bend is.
I start with the mark at 5 o'clock and see how it does. If your DFW is on the right side then the Right Rear Wheel should stay off the guide strip. It will be close but it should not touch. You will want the car to drift 2" in 4' to start. If you have a track with a timer you can then play with the adjustment. Before this is done you should check the car with just the back wheels on the car to make sure the back wheels are rolling straight.
I would suggest you buy Troy Thornes latest book - Building the Fastest PINEWOOD DERBY CAR. Lots of good info and an article on rail riding. You might have to get the book on Amazon.
Best of Luck.

[Stan Pope]

Since you are drilling the rear axle holes with camber, you are depending on the holes to be drilled true and the axles to be very straight. Even a half degree of bend in the rear axles can upset the alignment. Detecting that error is the reason for the "no front wheels" slide down a ramp. Correcting for errors with that setup can be a bit daunting, but it can be done ... with patience and perseverance. There are faster, more precise alignment methods that produce both true rear alignment and assurance that the rear wheels stay off the rail, but learning them may take a bit of work. When/if you get frustrated with the cut and try, ask and someone will get you guided into a more orderly alignment process ... one with rapid convergence to true.

The front axle hole (for the DFW) can be drilled with positive camber (end of axle down) of 1 to 2 degrees and toe-in of about 0.2 degrees and combine that with a slightly bent axle to adjust the drift to the rail. Or you can drill perpendicular to the side of the car and go with an axle bent about 1-1/2 degrees, angled down and slightly forward to get the desired drift.

Good racing!

[Speedster]

I have learned Troy Thorne's book "Build a Winning PINEWOOD DERBY CAR" is available at Michaels. It is the same as "Building the Fastest PINEWOOD DERBY CAR" with car designs and a few other things left out. It is a good book for a beginner and is readily available. Cost is $9.99.

[resullivan]

With all due respect to Mr. Pope, but I feel you are on the best and right track as far as the back wheels go. Minus his comment (which I believe he is referring to bending the rear axles) every single thing I have read, and every single person I have talked to swear by drilling vs bending the rear axles (I have done both). You do want to make sure you are drilling them correctly, but once you do it is a lot simpler to align the car because all you have to worry about is your DFW. Maybe he is talking about something else, or maybe I am totally wrong. You have multiple viewpoints, so that just leaves the fun part of testing both out and see which works best for you.

To me that is the fun part of PWD. People do different things and get different results. To just name a few, cutting all the way through the car, slots in the axles, tapping the wheel bore, fenders, and on and on. It just really comes down to what works best for your set of abilities and tools.

[Stan Pope]

With all due respect to Mr. Pope, but I feel you are on the best and right track as far as the back wheels go. Minus his comment (which I believe he is referring to bending the rear axles) every single thing I have read, and every single person I have talked to swear by drilling vs bending the rear axles (I have done both). You do want to make sure you are drilling them correctly, but once you do it is a lot simpler to align the car because all you have to worry about is your DFW.

The negative comments I've heard about aligning with bent axles over the past few years seemed to center on observations such as "I spent X hours adjusting the rear axles, and I still don't know if the alignment is correct!" I think the reason for these is that the forward/reverse roll test loses accuracy when the camber goes beyond 2-1/2 degrees and ignores the necessity for keeping the rears off the rail. And folks don't know an alternative method for aligning.

Keep in mind that success by "drilling" depends upon drilling true holes and selecting straight axles. Then you must know how to detect excessive variations in either and how to correct for those almost true holes and almost straight axles. Learnable? Certainly!

I showed in a recent video another method to align with bent rear axles. The time from "I've pushed the axles into the car" to "rears are properly aligned and planned drift is set" was a bit under 3-1/2 minutes. The method, once learned, is rapid and easy to apply because the adjustments converge rapidly on "correct." I proved the method to myself by taking an aligned car to a full-size Freedom Track and attempting to improve on-track times by tweaking the rear alignment. I could not improve the times and ended up taking the car back to the alignment board to reset the rear alignment!

One last reason to learn how to align a car with bent axles is that it can be applied effectively to even a poorly built car and help rescue Little Johnny's racing day, improving a car that doesn't reach the finish line to one that is competitive! And, once the axles are bent and installed, a den full of them could be well aligned in less than 1/2 hour!