Axle Diameter - .084 ?

Matt's Dad

Pinewood Ninja
Jan 5, 2017
26
2
3
I'm a bit confused - can someone help with this question... So in all of the rules that I've read it always states axles shall not be less than .084" or 2.13mm. I thought using .092 or .093 axles and having less tolerance between the axle and the wheel hole was better for speed. Why is this .084" thing even a rule?
 
If you are able to use wheels with small bores, it is advantageous to run axles with smaller diameters. Back when there was still a needle axle class, those cars could really fly, from what I hear.

That said, most rules forbid inserting any kind of bushing or foreign material into the wheel bore, so there's not much point in reducing the axle diameter.
 
If you are able to use wheels with small bores, it is advantageous to run axles with smaller diameters. Back when there was still a needle axle class, those cars could really fly, from what I hear.

That said, most rules forbid inserting any kind of bushing or foreign material into the wheel bore, so there's not much point in reducing the axle diameter.
I thought "fill and drill" was legal in pretty much everything but Box Stock?
 
I was told that such modifications to wheels would count as a bushing. I don't think it's allowed for classes other than Street Pro, Eliminator or Unlimited.

If anybody knows differently, please set me straight. :)
 
I was told that such modifications to wheels would count as a bushing. I don't think it's allowed for classes other than Street Pro, Eliminator or Unlimited.

If anybody knows differently, please set me straight. :)
You are might well be right. Just checked and under the "not allowed" there is a "bearings and/or bushings" line, and starting with Street Pro the "Bushings" part is not there.

So is filling and drilling considered a "bushing"?
 
Yes. And no. Lots of rules mention the adding and removing of material explicitly. This is adding something foreign to the bore, thus, a bushing. But it also would be same material bonded to and becoming part of the wheel.

It seems like a bit of a grey area in which you determine whether or not you are legitimately following the rules.

You have access to something allowing such machining? That's way beyond anything I have in my garage.
 
Yes. And no. Lots of rules mention the adding and removing of material explicitly. This is adding something foreign to the bore, thus, a bushing. But it also would be same material bonded to and becoming part of the wheel.

It seems like a bit of a grey area in which you determine whether or not you are legitimately following the rules.

You have access to something allowing such machining? That's way beyond anything I have in my garage.

I understand that position. I would say that an argument could be made that adding something to the bore like paint sealant is "foreign material". It does leave a (very small) coating behind that decreases the bore size (admittedly, a very minute amount, but still....)

All that said, the rules I looked up above merely say "no bearing/bushing" allowed, and then eventually drops it to "no bearings" as the classes go up.
So the question still remains, *what constitutes a "bushing"* ? Something you put in there as a solid and drilled a hole back through it? Or something you put in as a liquid that leaves a "bushing like coating" behind?

Fine line, I know.
 
At the NPWDRL bushing in the rules means adding material to the wheel bore to reduce the bore size.... Now you are right, technically a wax coating does that only on a very thin level... Until it is needed to be defined otherwise I think everybody knows what is meant by a bushing, but as I say this someone is probably applying coat #2056 of legend to their wheels bores and have reduced the size by .0005"on their way down to a .085 wheel bore...

Once again all crazy rules.... lets let the needles run with the big axles!
 
I think we should start a petition to get rid of that stupid minimum axle rule and the no bushing rule.... No one runs needles anyway.... there will be no advantage.
I agree about getting rid of the rule! It hints that small axles are faster.. maybe they are but not in a standard wheel. It's confusing for new racers.
 
I've always viewed that rule as part of the fossilized rules about wet paint and loose bits. They kinda need to be there as a formality, but no one serious about racing would even consider breaching.

Well... I can see someone using several coats of spray enamel and sending in the car before waiting the requisite two months to dry... So, I rescind that portion of my comment.
 
Hey, sticky paint IS a speed advantage! At least with a spring loaded gate anyway. Sticks to the start pin and gets a boost out of the gate.
 
Yes. And no. Lots of rules mention the adding and removing of material explicitly. This is adding something foreign to the bore, thus, a bushing. But it also would be same material bonded to and becoming part of the wheel.

It seems like a bit of a grey area in which you determine whether or not you are legitimately following the rules.

You have access to something allowing such machining? That's way beyond anything I have in my garage.

So if I take the shavings from where I lathed the wheel, grind them to a powder, bond the powder back into the bore, and remachine the bore to the smaller size, did I introduce "foreign material" or not? LOL.
 
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So if I take the shavings from where I lathed the wheel, grind them to a powder, bond the powder back into the bore, and remachine the bore to the smaller size, did I introduce "foreign material" or not? LOL.
Stephen, Stephen, Stephen.... o_O I knew I could trust you to come up with this sort of idea. ;) :)
 
Stephen, Stephen, Stephen.... o_O I knew I could trust you to come up with this sort of idea. ;) :)
If I'm not mistaken, this very thing was described in Doc Jobe's book.

If folks are allowed to fill and re-bore wheel bores, I imagine a whole new line of skinny axles is gonna crop up. :)
 
So if I take the shavings from where I lathed the wheel, grind them to a powder, bond the powder back into the bore, and remachine the bore to the smaller size, did I introduce "foreign material" or not? LOL.

Ok, the shavings are not a foreign material, but unless you melt them in ....the bonding agent might be considered foreign. ;) Especially if the shavings have an accent. :p
 
Ok, the shavings are not a foreign material, but unless you melt them in ....the bonding agent might be considered foreign. ;) Especially if the shavings have an accent. :p

OK, so instead of that, I'll melt the shaving into a drilled hole to make a rod, bore out the wheel, press in the rod with no glue, then rebore the wheel to the smaller size. No foreign material now, right? lol