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New Offical BSA Pinewood Derby Wheel

 

New Pinewood Derby Wheels

The pinewood derby season for 2009/2010 has brought the introduction of the new official BSA pinewood derby wheel for the pinewood derby kit.  Although not all kits will have the new wheels for the 09/10 season, there will be enough available that you need to know everything about them.  Let us introduce you to the new BSA pinewood derby wheel.  As of this writing, the best way to determine if the kit has the new wheels is to look on the outside of the box for the following number code stamped on the box, "IN0809", upside down in this case.  The old boxes have a simple "Z" marked on the outside.


[image]

Stamp Number on Boxes with New Wheels
(Check to be sure before purchasing at local store)

First, a description of the new wheels.  The new wheels, most importantly, are lighter than the old wheels.  The new wheels average about 2.6 grams each while the old wheels averaged 3.6 grams each.  This is a significant weight reduction and would alone make the new wheels faster.  Part of the weight reduction has been the coned inner wheel hub which has been reduced significantly as shown below.  (New wheel on the left)

Coned Wheel Hub in New Wheel on Left

 The new wheels also have been re-tooled so that there are three mold marks inside the wheel well as opposed to a single large mold mark on the tread surface as shown below.  The old wheel is on the right and the mold mark is near the top of the picture.  The new wheel is on the left and has a clean, unblemished tread surface. 

Mold Mark on Old Wheel on Right

 

Round and Round We Go (Or Maybe Not???)
The new wheels still have some radial imperfections as they are not perfectly round.  They average about .005" differential across the wheel surface but it is better than the old models.  This lack of perfect roundness can be corrected with the Pro Shaver XT or by purchasing the new DerbyWorx Precision Stock or Pro Stock wheels which have been machined perfect on the outer tread surface.  This provides a smooth, stable and fast ride down the track.
 

Wheel Bores

Just as in the old wheels, the new wheels are made from multiple new molds, in this case, numbered 1 thru 16.  The wheel bores vary by as much as .01" from one mold to the next and you need more consistency to have all 4 wheels sitting evenly on the track.  One can ream the wheel bores with the Pro Hub Tool to get the wheels to a consistent size (next section) or one can use wheels from the same mold number.  Better still is to have the wheel bores machined to a perfectly consistent size which DerbyWorx does with the Pro Stock Wheels.
 

The Biggest Difference in the New Wheel however...

Removing the Step in the Outer Wheel Hub of the New BSA Pinewood Derby Wheel

The new wheel is lighter and has a better outside tread surface but it has an unusual outer hub design.  It actually has a step or ledge in the outer hub (new wheel on the right) which presents no obvious speed advantages but does have some potential disadvantages. 

Step in Outer Wheel Hub of New Wheel on Right

It creates a second contact point on a beveled axle head and would contact it further to the outside of the axle head, meaning more surface contact area.  With no obvious speed advantage to the step, the predominant speed tip for the new wheel is to get rid of the step altogether.  The Pro Outer Hub Tool seen below was initially created to clean up the outer hub for the old wheel but is nearly perfect for the elimination of the step on the new pinewood derby wheel.  The outer hub tool needs to be sharpened first and that can be easily performed with a file which we will show you after we discuss reaming the wheel bores with the Pro Hub Tool.    

Wheel Bore Reaming

The wheel bore, simply put, is the inside of the wheel where the axle goes.  Molded Pinewood Derby car wheel hubs can vary in size by as much as .01" and you must resolve this situation to have the smoothest fit of the axle into the wheel.  The Pro-Hub Tool allows you to ream the wheel bore to the same size or to at least select wheels from your assortment that have a similarly sized bore radius.  This is a very important alignment tip as it allows the car to sit evenly on all 4 wheels with equal distances from the axle and wheel hub to the track.  You will need the Pro-Hub Tool to complete this speed tip. To perform this procedure:

1)       Test fit each wheel by sliding it onto the tool pin of the Pro-Hub Tool (flat side) as shown below.  If the wheel bore is too small for the tool, use steady hand pressure and a twisting motion to work the wheel on to the tool.  Remove the wheel and repeat 3 times.

Pro Hub Tool (Flat End)

2)       Once completed, choose another wheel and repeat step 1.

 

 Pro Outer Hub Tool

(Note: The Pro Hub Tool is required for use with the Pro Outer Hub Tool)

The Pro Outer Hub Tool will surely become one of the most popular tools for the 2009/2010 pinewood derby season for the following uses:

  •    Ensures accurate rotation of the wheel by squaring the outer wheel hub to the wheel bore for proper mounting of the wheel on the Pro Wheel Mandrel

  •    Reduces friction between the axle head and the outer wheel hub by eliminating flaws on the outer wheel hub and, most importantly

  •    Removes the step in the outer wheel hub on the new wheels which are a potential double friction contact point with the axle head.

Please note that the Pro Outer Hub Tool is intended for use on BSA wheels only.  It is not recommended for use on wheels made by any other manufacturer.

Sharpen the edge of the Pro Outer Hub Tool

If you are removing the step in the outer hub on the "new" wheels, you will first need to sharpen the cutting edge on the outer hub tool.  To accomplish this step, merely file the back side of the cutting edge with a flat file until you have created a small angle to the back of the cutting edge.  A picture of the outer hub tool with the edge sharpened is shown below on the left compared to a regular cutting edge on the right.  The specific angle is not important.  You do not need to sharpen the cutting edge of the outer hub tool if you are performing modifications to the "old" wheels.

 

Instructions for Using the Pro Outer Hub Tool

  •    Remove the protective cap from the square or flat end of the Pro Hub Tool and ream the wheel bores of each wheel per the directions above.

  •    Slide the Pro Outer Hub Tool onto the pin of the Pro Hub Tool with the cutting edge outwards.  To minimize the risk of injury, leave the protective cap on the coned end of the Pro Hub Tool.

  •    Place a wheel onto the pin of the Pro Hub Tool, spoke side first.

  •    With one hand holding both the Pro Hub Tool and the Pro Outer Hub Tool, press the wheel against the outer hub tool cutting edge with the other hand. Rotate the wheel three complete revolutions.

  •    Check the outer hub to view your progress.  If you are modifying the "old" wheels, you will not need to make too many revolutions with the outer hub tool to complete the process.  If you are removing the step in the "new" wheels, it will take quite a few more revolutions to get the outer edge of the hub even with the inner edge of the hub and completely remove the outer step.  Continue to check your progress after a few revolutions to make sure that you do not remove any excess material past the removal of the step.  The finished product in either case of the "old" or the "new" wheels should look like the wheels shown below. The non-modified "old" wheel is on the left and a modified "new" wheel is on the right.

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