Wheel rules question.

[Derby Dancin]

My district race is coming up and I'm not sure what changes I can make to my wheels to make them faster. Please take a look at these rules. Any advice appreciated!














Also not sure if we can bend the axels. Must have 3 wheels on the floor

[Vitamin K]

Truing the outer diamter of your wheels for roundness (or paying for a trued set) will buy you some speed. You could probably knock off a bit of weight on the wheels just on the outer diameter without too much reduction, just based on what the judges are looking for...maybe down to 2.2 grams or so?

Also, don't forget to polish the bores!

You could probably get away with 1-1.5 degree cant on your axles for alignment purposes, without changing the appearance of how the car sits.

[Derby Dancin]

Thanks! What grit paper would you recommend for trueing the tread? And what about trueing the bore?

[ngyoung]

I would not recommend trying to sand your wheels true. You are most likely to cause more harm then good. Giving them a light sanding to remove any flaws is fine, I would do that at around 1k-2k grit. Trying to spin them on a drill to sand them true to the bore is not going to give you much better wheel run-out then what you got from the factory. It looks like your rules would allow for most vendor's basic lathe turned wheels, leaving the double step, and leaving the inside edge of the wheel alone.

For the axles it looks like you can groove the axles and that is something doable with a file and a drill. The crimp marks are pretty much in the ideal location of where you would want the groove to be. As for getting your axles installed perfectly straight you can fudge that slightly. Most people are unlikely to ever get their axles installed with zero angle. If you bias your axles towards giving the rear a negative cant and the DFW a positive cant of just 1* it will allow the wheels to sit flat. I personally don't have a problem with doing that since even attempting to get the axles in straight you will likely have a 1* variance anyway but likely at varying directions.

They are allowing only 3 wheels to touch so you will want to drill the NDFW higher since you cant angle the wheel off the ground.

[Derby Dancin]

Thank you!

[Derby Dancin]

Ngyoung, do you recommend I bend the axels 1 degree?

[ngyoung]

Are you using the slots or do you have a setup to drill axle holes? IdeallyII would use a drill press with a "silver bullet" block and use a smaller pin to get the hole drilled at a 1* angle. If using slots I would just push them in at a very slight angle. For the rears you could take a small screw driver or something to pry up on the axle tips after installed to get your angle.

For the front dominant wheel you can give that a slight bend.

[Derby Dancin]

Thanks. I'm using extended wheel base with straight holes....any ideas? Shin?

[ngyoung]

If you already have holes done I think giving the back wheels a very slight bend will be fine. Depending on your axles they may already have a slight bend that you can work with to tune the rear wheels so they travel to the axle head when rolling forward and back. If not, giving them a slight bend to get the wheels to travel to the head should be fine. You may want to look up Stan Pope's weight bias tuning method. Just be careful bending, a 1* bend is barely noticeable. Stan has also posted an angle chart to show what different angle look like.

To bend put a wheel on the axle and make sure it is all the way to the head them mark the axle shaft where it sticks out of the wheel. Then clamp it in a vise just under the mark and take a flathead screwdriver against the mark and tap the back of the screwdriver handle with a hammer very gently. You may be able to use the heel of your palm instead of a hammer to get that small of a bend.