NPA - What Is Considered Stock?

BadWoolRacing Friday, 3/3/2023

Besides FTEs, and I recently read Color Shifters, what are good sources for 'stock' NPAs? Does anybody consider #20 sewing pins to be a legitimate substitute?


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SpyDude 3/3/23

Pretty sure #20's are about as close to a 'stock' axle as you can get. #17's work, too, but it allows the wheels to wobble just a tiny bit, and wobble kills speed.

  • I ask because I made my first brass tubed racer, with #20 pins recently, for a race that specified this was permissible. I'd like to use #20 pins as a regular axle mod but the copy/paste standard rules give me pause to think this wouldn't be acceptable. — BadWoolRacing

If a race rules state stock or NPA's I believe they mean just the axles that come stock on any HW/MB cars, whether NPAs or not. Any other item used as an axle wouldn't be "stock," as is my understanding.  Some allow tubes/custom axles, but most say stock/NPAs. Best to ask the race host.

I have heard of "Tubing", A while back when I first started researching customizing techniques.  I haven't tried it yet. I wanted to build some regular test cars to learn from.  I have some plastic tubes picked out.  I have decided to allow "Tubing" in all of the races I am trying to bring to the table.  

I wonder if a slightly bigger pin to the hole in the wheel could actually help solve the "egg" hole problem.  I little bit of extra sanding/polishing..

  • I asked about tubing not long ago and was to use brass because it has less tendency to bend/flex. I bought a pack of four, 1/16 sized, at Hobby Lobby. There are two numbers on the package - 100131 & 5125. — BadWoolRacing
  • I ordered some drill bits to make the wheel hub holes more true. I just twist them through manually. Doesn't appear as though I can attach a photo to replies like this so here is the description from Amazon: "uxcell PCB Drill Bits 0.8mm Tungsten Carbide Rotary Tool Jewelry CNC Engraving Print Circuit Board Micro Drill Bits 1/8 Inch Shank 5 Pcs" — BadWoolRacing
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dr_dodge 3/4/23

We are trying to set rules for the drag strip at the slot shop, and want to throw this out there

there is the concept of rules that are hard to enforce/determine outcome
If you said no pins/tubes, etc  it would be hard to tell on some builds unless the car is taken apart

I say this not to encourage cheating,
more as to when setting rules a means of "inspection enforcement" should be considered

as an example:
If I said; "no lube", determining if the wheels were lubed, then cleaned would be hard to figure out,
puts the inspector in a bit of a judgement call situation, because the determination is not easy and obvious.
so it's easier to not ban dry lube,
but to just say no dirty tires/wheels (white paper test)

  • Not trying to usurp any rules but I wonder if #20 pins just make sense as an alternative to Mattel produced NPAs since they are essentially the same thing - a little bitty metal stick plated in nickel...... — BadWoolRacing
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redlinederby 3/4/23
Site manager

Check out this FTE FAQ to get some more details on FTEs and NPA axles.

  • I think I have read this one before, quite a while back. I guess I just need to up my hunt for NPA donors, both from the pegs and in the secondary market.. — BadWoolRacing

Say I buy a Color Shifters off the pegs today. I've read that the wheels themselves can be junk so I just need the axle. The only way I know to get wheels off is to cut the axle and slide them off. At this point I'd need to brass tube a new axle together, using the wheels I want on the Color Shifters' axle halves. Is this a common method you veteran builders use to make faster axles while still staying compliant with the stock axle rules?

  • That is the definition of a modification. The opposite of stock — Uncle_Elvis
  • Doing the tubing that way is still customization and not stock anymore. — Garden_Super_Speedway_Park
  • Actually it depends on the race rules. Tubing axles doesn't always mean modification. There's a difference between making retail axles work vs using something else to make an axle (like a hat pin). You just need to check with the host if you want clarity. — redlinederby
  • @redlinederby - That is a compromise I can get behind, using actual axles from the likes of Color Shifters but mounting them in the chassis with brass tubing. This would open up using a wide variety of wheel types/styles while still using Mattel produced hardware. I'll definitely check with race hosts about this option. — BadWoolRacing

So #20 pins and brass are not an option in most cases. What are the most common sources on the pegs right now for NPAs? I presume Color Shifters are one, anything else? Ultra Hots from Target?

  • I bought a few of those Ultra Hots, there is no way that they are NPA. — WorpeX
  • NPA's as far as I know only exist on Color Shifters. The Hot Ones used to be considered faster because the axle diameter is smaller, but not sure if the modern Hot Ones have the same smaller axle.. UH are not NPA/FTE. — FeralPatrick
  • Thank you, FeralPatrick. More Color Shifters it will be, then. — BadWoolRacing
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EnZedRacing 3/6/23

*Asks Uncle Google what is NPA & FTE*

  • “ No Particular Answer” and “Forgot The Engine” — SpyDude
  • Cheers for clearing that up SpyDude (slaps forehead lol) — EnZedRacing
  • nickel plated axles, faster than ever (wheels) — dr_dodge
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