BSA wheel diameter go/no go limits?

Discussions on race planning, preparations and how to run a "fair" and fun race.
Post Reply
User avatar
Go Bubba Go
Pine Head Legend
Pine Head Legend
Posts: 1201
Joined: Sat Nov 18, 2006 1:09 pm
Location: Northern, Illinois

BSA wheel diameter go/no go limits?

Post by Go Bubba Go » Fri Jan 25, 2013 11:43 pm

Just curious, for those BSAers that use a Go / No Go gauge for checking wheel diameter, what dimension do you use for your gauge?

1.180 inches?

1.170 inches?

Looking at 1.180 as our rules are pretty restrictive (light sanding only), but getting some pushback from folks who think you can't true a new wheel without getting under 1.18.

Comments?


"Who's Grandpa's neighbor?"... Phil Davis, Down and Derby

Speedster
Pine Head Legend
Pine Head Legend
Posts: 1334
Joined: Sat Feb 18, 2012 2:48 pm
Location: Toledo, Ohio

Re: BSA wheel diameter go/no go limits?

Post by Speedster » Sat Jan 26, 2013 5:38 am

You asked for Comments so I should be able to stay on Topic.

It doesn't matter. Vendors advertise machined wheels at 1.180. I'm curious as to how someone can make a wheel round with (light sanding only). I've read everything on DT what experts have to do using lathes to make a good wheel. We have that same stupid rule. I used "Medium Sanding" last year and I've felt guilty ever since - - plus the lousy wheel wasn't round. What do you think is really in the minds of the people who are complaining about the diameter restriction?

A Wise Man once said, "Use the tread mark and put the calipers away". Fortunately, we do use the tread mark.
Best,
Bill Klingler



knotthed
Master Pine Head
Master Pine Head
Posts: 169
Joined: Tue Dec 13, 2011 10:01 pm
Location: Northeast, Illinois

Re: BSA wheel diameter go/no go limits?

Post by knotthed » Sat Jan 26, 2013 10:05 am

Here are some wheel specs posted on the internet and I suspect these were posted when the new wheels came out in 2009.

Winderby - Wheel Diameter:1.184" - 1.187"
MaxV - Raw Wheels: 1.182" to 1.185"

So pubished data suggests; 1.182" - 1.187" for diameters at time of initial release. (Do we know the manufacturing specifications from BSA?)

Now lets say that there is variation in the manufacturing process due to die/mold wear and refurbishment, but for the sake of this discussion lets leave this out of the equation.

Let's also agree that there will be differences in measuring the size of said wheels (that's why manufacturing industries use GR&R's - gage reliability and repeatability tests), but for the sake of this discussion lets leave this out of the equation.

Let's also say that standard gaging practices would dictate that your gage would need to have resolution 10x greater than your specification, so if we were measuring to .001" you would need a gage that is capable of measuring to .0001" to have accurate readings on size, but for the sake of this discussion lets leave this out of the equation.

If we take a low end wheel at 1.182" does your group all agree that a cub and or parent can remove less than the average thickness of a human hair (.003) to true up a wheel? :whew: Now it might be easier if you are lucky enough to get some large wheels at 1.187".....

Let's also keep in mind that when removing material from a wheel the amount of material removed from the outside surface is half of the difference in diameter. So a cub and or parent would have to remove .001 or less from the outside diameter surface to keep the wheel within the 1.180 specification.

Doesn't sound very practical to me given the circumstances :thinking: :scratching: :eek: :wall: :sweating: :idk:

Please keep us informed and let us know what your group decides.



User avatar
FatSebastian
Pine Head Legend
Pine Head Legend
Posts: 2646
Joined: Wed Jun 17, 2009 2:49 pm
Location: Boogerton, PA

Re: BSA wheel diameter go/no go limits?

Post by FatSebastian » Sat Jan 26, 2013 3:06 pm

Welcome back GBG! It's been a while since we've last heard from you.
Go Bubba Go wrote:our rules are pretty restrictive (light sanding only), but getting some pushback from folks who think you can't true a new wheel without getting under 1.18.
Do new wheels need to be "trued"? If so, can one actually "true" the new wheels by "light sanding only"?

There was some discussion last month about which criterion might be best in order to catch professionally modified wheels; I think it was concluded that either criterion can be sidestepped by professionals, but 1.180" is harder.



User avatar
MaxV
Merchant
Merchant
Posts: 487
Joined: Wed Jul 02, 2003 5:45 pm
Location: Phoenix, AZ
Contact:

Re: BSA wheel diameter go/no go limits?

Post by MaxV » Sun Jan 27, 2013 11:46 am

When I introduced the Wheel Go/No Gauge, my intent was the following:

- No Wheel Modification Allowed - If the wheels may not be sanded or modified in any way, then use the 1.180 OD gauge and the .360 width gauge.

- Wheel Modification Allowed - If the wheels may be sanded or lathed, then use the 1.170 OD gauge and the .320 width gauge.

Of course, these dimensions and rules need to be clearly stated in the official rules so that everyone is aware of them.



knotthed
Master Pine Head
Master Pine Head
Posts: 169
Joined: Tue Dec 13, 2011 10:01 pm
Location: Northeast, Illinois

Re: BSA wheel diameter go/no go limits?

Post by knotthed » Sun Jan 27, 2013 1:53 pm

Randy,

That is great background information on your gage!

Thanks for posting.



Speedster
Pine Head Legend
Pine Head Legend
Posts: 1334
Joined: Sat Feb 18, 2012 2:48 pm
Location: Toledo, Ohio

Re: BSA wheel diameter go/no go limits?

Post by Speedster » Sun Jan 27, 2013 3:23 pm

Randy, I think no one is concerned with your gauge or criticizing you for anything. The wheels can easily be measured with a micrometer. I think the issue is showing you cannot stop a dedicated builder and 99.99% of the rest of the folks don't care what rule is made on the wheels.



knotthed
Master Pine Head
Master Pine Head
Posts: 169
Joined: Tue Dec 13, 2011 10:01 pm
Location: Northeast, Illinois

Re: BSA wheel diameter go/no go limits?

Post by knotthed » Sun Jan 27, 2013 4:01 pm

Speedster,

I think Randy's gage is a great idea for race organizers that want to establish a size limit.

I cannot imagine measuring every entrants wheels with a micrometer! That would be unbelievably time consuming. Randy's gage offers a very quick way to establish compliance of the wheel diameter to a set size.

I also like the idea that you must still be able to see the thread dots on the side. Does anyone know at what diameter the thread dots dissappear at?

The thread dots are obviously the most parent/cub and race organizer friendly - no gages needed. I could see the dots causing some issues though - how much of the dot must be visible, should it be all the way around the wheel? Different peoples eyesight is of different quality etc...

There is no doubt that Randy's gage would offer the most consistency in my opinion. The only time you might have a problem is if the thing is dropped or stepped on it could become bent and out of size tolerance, as with any type of gage it should be double checked before you start using it.



User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6888
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Re: BSA wheel diameter go/no go limits?

Post by Stan Pope » Tue Jan 29, 2013 12:57 am

(1) FWIW, I turned down four orange wheels (made in USA and sold at BSA store during the past year or two) to "good" running state with diameter 1.182". (They won't be "run" but rather they will be used to evaluate some new axle treatments. I was not thinking about this thread when I turned the wheels or I'd have checked the original OD's.)

(2) Every racer deserves the right to know when they are building that difficult to alter at race time parts are legal without haveing to buy a relatively expensive gage. Specifically, while a size limit for wheel diameter is easy to check during inspection, failure is difficult to correct at that time. The term "light sanding" is too imprecise to be a guide during building. And since there is advantage to heavier "light sanding" than lighter, the builder risks DQ if the "light sanding" is too heavy and poorer performance if the "light sanding" is too light. The builder should be able to know that his wheels are legal as he is preparing them ... without buying a gage or caliper. This is why I proposed the Wotamalo OD rule as based on wheel features instead of wheel diameter.


Stan
"If it's not for the boys, it's for the birds!"

Speedster
Pine Head Legend
Pine Head Legend
Posts: 1334
Joined: Sat Feb 18, 2012 2:48 pm
Location: Toledo, Ohio

Re: BSA wheel diameter go/no go limits?

Post by Speedster » Tue Jan 29, 2013 6:51 am

Stan, looking forward to the info on the axle treatments. Do you think this information might be available before March 16th? Thank you.



rpcarpe
Master Pine Head
Master Pine Head
Posts: 734
Joined: Wed Mar 17, 2010 11:58 am
Location: Huntsville, Alabama

Re: BSA wheel diameter go/no go limits?

Post by rpcarpe » Tue Jan 29, 2013 11:40 am

We also avoid the wheel size controversy by allowing the kids to modify their BSA wheels in anyway they want except for two:
- Cannot increase diameter
- Cannot make the wheel bore smaller

I've got Dads and older brothers learning to work wheels on the lathe, and Cubs working the Wheel Shaver to lighten and true their wheels. I also keep a jar of 'wheel attempts' to study before embarking on extensive wheel modifications.


My wife started a new support group... Widows of the Pinewood Derby.

User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6888
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Re: BSA wheel diameter go/no go limits?

Post by Stan Pope » Tue Jan 29, 2013 1:38 pm

:offtopic:
Speedster wrote:Stan, looking forward to the info on the axle treatments. Do you think this information might be available before March 16th? Thank you.
I estimate about 4 more hours of case preparation, 40 hours of data gathering and a few hours of data crunching. The remaining question is whether the results are worth publishing. If so, then a bunch more hours of preparation. :pray:

At this point, I have completed the experimental plan and data sheets, but I'm only a few hours into case preparation.

I am slowed a bit because my camera is out on loan!


Stan
"If it's not for the boys, it's for the birds!"

Speedster
Pine Head Legend
Pine Head Legend
Posts: 1334
Joined: Sat Feb 18, 2012 2:48 pm
Location: Toledo, Ohio

Re: BSA wheel diameter go/no go limits?

Post by Speedster » Tue Jan 29, 2013 3:51 pm

Definitely worth publishing. If anything shows a gain, or loss for that matter, I'd like to try it out.



User avatar
Ickabod
Pine Head
Pine Head
Posts: 97
Joined: Thu Dec 13, 2012 2:50 pm
Location: Omaha, NE
Contact:

Re: BSA wheel diameter go/no go limits?

Post by Ickabod » Tue Jan 29, 2013 10:10 pm

Speedster wrote:Definitely worth publishing. If anything shows a gain, or loss for that matter, I'd like to try it out.
+1


There are only two seasons: baseball season and The Void. - Jonathan Yardley

Post Reply