Centerlock wheels

Question:
Pit crews obviously use some kind of air ratchet to take theirs on and off.
Are they calibrated somehow? No torque wrench to get it 'just right'.

Never seen a wheel fall off during a race, so whatever they do seems to work.
99/100 of center lock race stuff have now integrated safety system that works when the air gun is puch onto the hubb !! no need to take off with one hand any pin or watever needle

99/100 of these airguns are manufactured in Italy by a company named Paoli and they are built for this purpose only ; there are left and right gun and each one can do the torque only on this way so youcan't use one to the wrong side
Then each team set the pressure for the nitrogen bottle in order to reach the torque asked by ingineer or manufacturer of special nuts ( mostly now an Austrian brand named Pankle)
99/100 of these nuts are now steel ( no more aluminium !!they sized quickly after 2/3 changes!!) and their thread is protected with a very very secret coat coming from aerospace industry and able to lubricate this strong and speed "screwing" onto the male thread

Just for information those specific airgun cost from 3500 to 4500 $ and each nut ( depending on the manufacturer and coating ) is more or less 350$ and last one week end
And the little sytem included into the center of hubb is about 1000 $ of machinig parts !!

When you watch on tv some F1 or prototype loosing a wheel at a100/100 is because during the change the mecanic did a wrong movment loosing the nut and puches the airgun like a "blind" robot without checking he was srewing something to the hubb!!!!!
 
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Just re-torqued my centerlocks after a bit of use. They were all still seemingly pretty close to the original torque.

I think I do need to get locking pins, as Julian suggested.

Re the Bunyan question, yeah, I seem to recall that John was Paul's bigger brother. Had to use a typewriter the size of a Volkswagen to type out the Pilgrim's Progress! He was even bigger than Paul, but liked to keep a low profile, hence the writing career. I'm pretty sure that's it! (Thanks for the save and humor, Doc!)

Here are a couple of pics of the 3/4" torque wrench tightening the nuts. I am using the special aluminum-based anti-seize that is used on the Porsche Cup cars with centerlocks.



Apparently the torque setting is accurate only if you are using the wrench roughly parallel to the ground, and only if held right at the end of the handle- or so I've read.



As mentioned before, the left side has left-hand threads, so you have to be careful about which way to apply torque to tighten or loosen.
 
Ken, that's a hinge design from another builder. It's a very nice design, and allows the nose to open almost 90 degrees even with the deep track splitter. You need to have the lift kit raised up with the deeper splitter to get that, though. With the normal splitter just open and go. Like Rumbles' build it joins the splitter to the nose and pivots the whole shebang. PM me if you want more details.

Alex, I am torquing the nut to 330 ft lbs. somewhat arbitrary I guess, but it's near what the Porsche Cup cars do.
 
So we have been doing it wrong all these years?



This is not me, or one of my cars, but everyone running a sprint car just goes for *really tight*. I've never had one come loose unless someone forgot to put a wrench on it.
 
Will, when tightening your rims do you have any difficulties or can you tighten the nut with basically a pinky finger?

Reason I ask is because I installed mine for the first time yesterday. to get to 300ft-lbs I was expecting to have a heart-attack, especially when i've watched people installing knock-offs and hammering the living piss out of them. But I put my torque wrench on it and it's like beyond easy to install, basically can tighten with just my pinky finger. My wrench is 5 1/2 feet long and I totally get the power of leverage, but i keep thinking to myself there's no way it can be this easy...can it?
 

Scott

Lifetime Supporter
Alex, maybe you have a super pinky from driving all of those high HP cars;-)

T=F*D*sinθ where F is force, D is the length of the wrench and θ is the angle between the force and the wrench. If you apply the force perpendicular to the wrench, that term goes to 1. So, the force you need to apply is T/D = 300/5.5 = 54.5 pounds of force applied perpendicular to the wrench. That’s a lot of force for a pinky.
 
Will, when tightening your rims do you have any difficulties or can you tighten the nut with basically a pinky finger?

Reason I ask is because I installed mine for the first time yesterday. to get to 300ft-lbs I was expecting to have a heart-attack, especially when i've watched people installing knock-offs and hammering the living piss out of them. But I put my torque wrench on it and it's like beyond easy to install, basically can tighten with just my pinky finger. My wrench is 5 1/2 feet long and I totally get the power of leverage, but i keep thinking to myself there's no way it can be this easy...can it?
I was surprised at the relative ease that 330 came up when I was tightening them as well. Then I looked at my super-hunk biceps and thought, "well, of course!". :)

My wrench is a mere 4 feet long, but yeah, it doesn't take much. If those sprint car guys are really leaning into it, I'm guessing they are getting much more than the 330 I was shooting for.

Because I was skeptical of the process as you were, I went back a week later to check them. They were all still right where they should have been, so I guess it's repeatable, in any case.

Scott's numbers do seem about right- apparently it just doesn't take much when you have a pretty long lever.
 
well, maybe a pinky is a bit of an exaggeration ;)

to me 300ft-lbs on my wrench feels like 50ft-lbs on my 3/8'' drive torque wrench, which, based on Scott's numbers, would put the two in the same ballpark.

But yea, wow, I never really appreciated leverage before.....I had convinced myself the last 4yrs tightening/removing these rims was going to be a monstrous pain, but it's even easier than 5 lug.

Makes me wonder how much torque people are getting out of their knockoffs when they whail on them with a hammer ... no wonder some end up having to cut the rim off, lol

btw,do you tighten to 340ft-lbs w/ wheels in the air, or do an initial tighten to say 250ft-lbs in the air, then final tighten on the ground? I get you want to make it nice and tight in the air so the rim goes on straight, but is it okay to do final tighten on teh ground since it's so awkward (atleast i think it is) to tighten in air
 
well, maybe a pinky is a bit of an exaggeration ;)

to me 300ft-lbs on my wrench feels like 50ft-lbs on my 3/8'' drive torque wrench, which, based on Scott's numbers, would put the two in the same ballpark.

But yea, wow, I never really appreciated leverage before.....I had convinced myself the last 4yrs tightening/removing these rims was going to be a monstrous pain, but it's even easier than 5 lug.

Makes me wonder how much torque people are getting out of their knockoffs when they whail on them with a hammer ... no wonder some end up having to cut the rim off, lol

btw,do you tighten to 340ft-lbs w/ wheels in the air, or do an initial tighten to say 250ft-lbs in the air, then final tighten on the ground? I get you want to make it nice and tight in the air so the rim goes on straight, but is it okay to do final tighten on teh ground since it's so awkward (atleast i think it is) to tighten in air
Sorta-tight in the air, then final-tight on the ground.
 
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