GrandPrix Race Central - New BSA Wheels and Axles

Posted on Tuesday, July 28 @ 15:01:49 EDT by gpraceman

The Boy Scouts of America has started to ship a new wheel design and slightly different axles. These changes do have performance implications and may necessitate some rules changes.

First, I''''ll get the new axles out of the way. If you were hoping for an axle that requires less work to prep (like Awana and other organizations use), then you will be sorely disappointed (as I was). The only difference between the new axles and the old ones is that they are about 1/8" shorter in length. That may not seem like a big deal, but with less of the axle shaft sticking into the wood, there may be a bit more of an issue with wheels coming off during a race. The only reason that I can see for this change was BSA trying to save on material costs.

Now, onto the wheels, which there have been some bigger changes, some that should reduce prep time. Gone is the mold mark in the middle of the wheel tread. Instead there are 3 small mold marks, in a triangular pattern, on the inner sidewall. To me, that is a most welcome change. It promises to significantly reduce prep time for the wheel tread and possibly make for wheels that are less out of round. Other changes include a slightly reduced wheel diameter, thinner wheel tread, skinnier axle hub, end of the hub has been coned (rounded), and the area where axle head contacts the wheel has been "stepped down" instead of being flat.

With all of these changes, the wheels end up weighing about 2.6g. The older wheels are about 3.6g. That is a pretty significant weight reduction. With less mass, there is less moment of inertia (force needed to get the wheel rolling), which means that cars with these wheels can get off the start line faster than cars with the old wheels (everything else assumed to be the same). That could be a significant advantage, as many people that have tried reduced weight wheels can attest. The stepped axle head contact area seems to be the only change that may negatively affect performance. Braking torque will be increased if the contact between the axle head and the wheel is further out from the center of the shaft.

BSA really does not seem to consider the new wheel design anything special, which I found surprising. Many people within the BSA supply chain are not even aware of the new wheel design, which again seems to point to BSA not viewing the new wheel design as anything special. They had old molds that needed to be retired, so had new molds made up. In the process (and this is my speculation), they wanted to save on material costs, thus the reductions in thickness to parts of the wheel, as well as the reduced outer diameter. Another sign is that BSA is not waiting to purge their current inventory of the old wheel design before shipping the new one. They are currently shipping a mix of the new and old. No one yet has reported seeing the new wheels in the kits, just in the wheel/axle packs. Some people have found these new wheels (even the colored variety) at their local Scout Shops, but many Scout Shops have not seen them yet. Online derby suppliers, if they have any in hand, seem to be stashing them away until they become more readily available.

If you go to your local Scout Shop to hunt for these new wheels, how can you tell the difference between the new and old? Well, the most obvious way is the lack of a mold mark on the wheel tread. Another obvious means is that the lettering on the outer sidewall of the old design uses the trademark symbol (TM) for the term "Pinewood Derby", whereas the new design uses the registered trademark symbol ®. BSA received their registered trademark in 2005, so that makes sense to me.

So, what impact could these new wheels have on your pack, district, and council race rules? Well, that depends on how nit-picky the rules are. If they are simply the "rules in the box", then not at all. However, if the rules specify certain limits on wheel diameter, tread thickness, wheel weight, or no hub coning then changes will need to be made. A complication is that BSA is shipping a mix of the new and old design. Some may want to just prohibit the new wheels until they are more readily available. However, if they are "official" BSA wheels, how can you really do that and not get a lot of arguments from racers (parents that is)?

Overall, I like the new wheels but am disappointed that BSA did not come out with axles that require less prep work. The wheels do look to require less prep work to make race ready. That means it will be easier for novice racers to be competitive, which is a good thing to me (raise the level of competition and promote participation). BSA''''s roll out of this new design seems to be the biggest problem. Many people will be scrambling to get the new wheels to gain an advantage over the multitude that don''''t know about these new wheels. How will race coordinators deal with the issue of new and old wheels? Will they even know about the issue until strange wheels show up at their race? Will rules be addressed, as needed, in enough time to give everyone a more even playing field? That will all be interesting to see.

If you are curious to see the new wheel and axles, here''''s some links to photos of them:

Wheels
http://derbytalk.com/images/gallery/wheels/NewBSA1.jpg
http://derbytalk.com/images/gallery/wheels/NewBSA3.jpg
http://derbytalk.com/images/gallery/wheels/NewBSA4.jpg
http://derbytalk.com/images/gallery/wheels/NewBSA5.jpg
http://derbytalk.com/images/gallery/wheels/BSANewWheelDia.jpg

Old axle (longer) next to new axle (shorter)
http://derbytalk.com/images/gallery/wheels/BSAAxleComparison.jpg

You are welcome to join in on the discussion of these new wheels and axles at our Derby Talk forum, http://derbytalk.com/viewtopic.php?f=37&t=4946

Sources for this story include:
Randy Metz, Pinewood Extreme
Bill Launius, Derby Worx
Various members of the Derby Talk and PWD Racing Forums.