Care & Feeding of Knock-Off / On wheels

[Jac Mac]

I believe the only two questions remain for a Male Nut ASSY:
1. Is it LHT/LHS-RHT/RHS or RHT/LHS-LHT/RHS.
2.And given the examples to date- Is the Spline Drive (Wire Wheel steel spline's) versus Pin Drive (Alloy Wheel/Hub ) the reason that the thread direction is ' apparently ' reversed.

One further point of interest or conjecture-- While perusing a book on Corvettes yesterday I noticed two photos of cars fitted with the knock on/off hubs, One car with the 'ears' pointing fwd, the other with the 'ears' to the rear ( and yes I checked that they were both LHD in case someone flipped the negative at the printers ) so it looks like even GM were not sure of what they were doing ( that did not really surprise me ).
One other thing that does not surprise me is the lack of tech input from any manufacturers on this, they probably dont know why they do it either, maybe this comment will injure their pride enough to draw them out.

Jac Mac (Scott if you are having trouble reading the text I can email it too you, but you should be able to save & enlarge it )

 

[Scott Calabro]

Thanks Jac,

I'm good to go.

When #875 gets here I'll have a known quantity and complete build manual to refer to, for the correct technical and installation data.

I appreciate the thought though.

Russ,

Thank you for the clarification.

:chug:

Best,
S

 

[Russ Noble]

I believe the only two questions remain for a Male Nut ASSY:
1. Is it LHT/LHS-RHT/RHS or RHT/LHS-LHT/RHS.
2.And given the examples to date- Is the Spline Drive (Wire Wheel steel spline's) versus Pin Drive (Alloy Wheel/Hub ) the reason that the thread direction is ' apparently ' reversed.

One further point of interest or conjecture-- While perusing a book on Corvettes yesterday I noticed two photos of cars fitted with the knock on/off hubs, One car with the 'ears' pointing fwd, the other with the 'ears' to the rear ( and yes I checked that they were both LHD in case someone flipped the negative at the printers ) so it looks like even GM were not sure of what they were doing ( that did not really surprise me ).
One other thing that does not surprise me is the lack of tech input from any manufacturers on this, they probably dont know why they do it either, maybe this comment will injure their pride enough to draw them out.

Jac Mac (Scott if you are having trouble reading the text I can email it too you, but you should be able to save & enlarge it )

Jac Mac,

As I read and understand it the reason the wire wheels tighten the opposite way is because they have a female cone on the spinner thus the epicycylic forces operate in the opposite direction because the weight of the car is held by the top of the nut, as opposed to the bottom of the nut with the GT40 type male cone spinner.

I believe that you're not going to get any manufacturer admitting they are wrong, or changing the way they do it because the implications of recalls or legal action in the case of mishaps is too onerous. It would be nice though if they could dazzle us with valid scienctific reasons for doing it their way.

Cheers

 

[Mike Drew]

Failing that, for my first test session I'll put them on the way I consider to be right and just snug the spinners up to about 50 ft-lbs and loosely lockwire them and see if they tighten or loosen.

(snip)

You can be sure I will post the results of the track test.

If indeed you plan to only tighten the spinners to 50 ft/lbs (instead of the recommended *350* ft/lbs), your resulting post will likely be one of the more exciting we've seen here for quite some time.

 

[Russ Noble]

Haha Mike,

Boring and mundane are not part of my vocabulary! I'm prepared to put my body on the line to back my judgement. Besides my pit crew have said they will resign if I do the RHT/LHS thing and I'm getting too old to push the thing around the pits by myself.

You want to donate me an in car cam for the test?:lol:

Cheers

 

[Jac Mac]

This supports the data from Chapman re the 'Rudge' design. Borrani wires, I dont know the significance of the '42' number ( perhaps a torque value?) but the arrow and the word 'OFF' are quite clear in the photo. Interesting that the design allows a more accurate and presumably heavier 'hit' to undo the spinner than to tighten, which would give credence to the 'self tightening ' mentioned in the text.

Jac Mac

 

[Mike Drew]

More to the point, the text in the drawing supports the theory espoused by everybody in the world except for Lotus, in that the nuts are turned "back on", i.e. rotated towards the rear of the car (in the opposite direction of normal wheel rotation while underway) to tighten (which means left-hand threads on the right side of the car).

It stands to reason that the designers of the wire wheel nuts would shape them to favor removing them. You would almost assuredly be able to achieve more torque hitting the flat side, than the curved side of the nut. Were they the other way around, it would be easy to hammer them on so hard that you then couldn't remove them!

 

[Russ Noble]

Mike

Respectfully, you are missing the point here. Jac Macs illustration is for Borrani wires. Everyone agrees on the wire wheel scenario with the female cone nut.

But when the male cone nut centrelock system is used on alloy wheels and anywhere a male cone nut is involved (i.e. Lotus Elan wheels) the forces are reversed and the wire wheel setup when applied to GT40 alloys etc is just plain wrong.

Cheers,

 

[Jac Mac]

More to the point, the text in the drawing supports the theory espoused by everybody in the world except for Lotus, in that the nuts are turned "back on", i.e. rotated towards the rear of the car (in the opposite direction of normal wheel rotation while underway) to tighten (which means left-hand threads on the right side of the car).

It stands to reason that the designers of the wire wheel nuts would shape them to favor removing them. You would almost assuredly be able to achieve more torque hitting the flat side, than the curved side of the nut. Were they the other way around, it would be easy to hammer them on so hard that you then couldn't remove them!

OR perhaps they are aware of the self tightening process of the Rudge design, they -unlike you- do not appear to use safety wire.

Go to --'All GT40-Thread'New Guy With Pictures'-Post #9'---- Note how the cars were changed from Borannis to Halibrand mid meeting- might I be so bold as to suggest that the new wheel / hub assy's were fitted with threads orientated as per those being removed.

You can easily prove us all wrong yourself - swap the front hubs side for side on your Cobra- and check it out.

Jac Mac

 

[Keith]

Was that photo featured in Motorsport recently Jac? Quite coincidentally, I was in a doctors waiting room today and spotted a Feb 2007 edition Motorsport with an ad that featured a picture of a wire wheel with exactly that info engraved on it. Not sure which car though...

But surely, everyone knows that the answer to Life, The Universe and Everything is actually 42...

Not sure about the question though.....

 

[Sandy]

Don't most of the wire wheels also have splined inners? I know the older Lambo's and Ferrari's do as I have mounted tires on them and noticed the splines, same for most of the wire wheels I recall seeing.

That being said, time to move on...

Where do I get these clips, I like these better then the diaper pins. Might be a custom spring, but interesting way of doing it.

For tools to tighten the spinner, I have one that was from one of the cobra places that is a huge hunk of aluminum that you put a bar in the back for leaning on, but I'll likely use the bolt and the impact/big torque wrench.

 

[Jac Mac]

Bit of further info on this matter, I checked with a contact in the Aussie V8 Supercars who made some enquiries; Most if not all teams are using RH Thread on BOTH sides of these cars- (Large Male Nut/Pin Drive)- he could not give me a reason why other than possibly to avoid the confusion that would result from having Rattle guns configured for either side and with LH & RH circuits the pit crews would have to be trained for one side of the car only if threads were LH/RH.

So we are no further ahead, while some cars shed wheels in this series this is most often due to a hurried wheel change etc, or a car being dropped off the air jacks too soon.

Jac Mac

 

[John Owen]

Thank you Jac Mac. Knew you were a good guy. I rest my case. This only applies to modern rigid wheels and hubs. On track there is little chance of encountering a tread thrown from a truck, misc animals, rocks, ladders etc. As to public roads, the only real risk for a properly installed spinner is the detritus left by other vehicles and nature, real debris that will unwind the spinner.

 

[Jonathan Strain]

I don't buy the road debris arguement. I think it is unlikely that debris would strike the spinner, and if it did what's to say it would not hit the top of the spinner rather than the bottom. I would bet on the self tightening issue being key. Racers are probably just using enough torque to be sure they will not come loose.

 

[Russ Noble]

Go to --'All GT40-Thread'New Guy With Pictures'-Post #9'---- Note how the cars were changed from Borannis to Halibrand mid meeting- might I be so bold as to suggest that the new wheel / hub assy's were fitted with threads orientated as per those being removed.

Jac Mac

Just going back through this thread. The photo Jac Mac posted (post#52) of the GT40 with the Borranis, from the look of the nuts those Borranis are fitted RHT/ RHS.

That further muddies the water! Did the Borranis for GT40'shave a different construction to "ordinary" wire wheels.

That being the case, there would be no thread direction issue swapping from Borranis to mags.

Cheers

 

[Jac Mac]

Just going back through this thread. The photo Jac Mac posted (post#52) of the GT40 with the Borranis, from the look of the nuts those Borranis are fitted RHT/ RHS.

That further muddies the water! Did the Borranis for GT40'shave a different construction to "ordinary" wire wheels.

That being the case, there would be no thread direction issue swapping from Borranis to mags.

Cheers

Now its you not reading the text in full Russ---- NOTE- To Tighten or Fit the Borranni wheels the knock ON is hit on the curved/leading edge of the spinner, To remove the knock OFF is clouted on the straight/trailing edge of the spinner, This indicates LHS-RHT/RHS-LHT as per Rudge design. Other pics of THAT white car show both sides have spinners fitted with curved leading edge in direction of forward rotation. The dwg in post 66 is from another car #1050 which supports the Borrani/Rudge principle.
The Borrani are spline drive, yet the Halibrands which were fitted mid/meeting by Shelby etc are pin drive, so those splined hubs must have been replaced at the same time-which raises the question--Were the threads of the "NEW' hubs fitted as per the OLD for just that reason--the old ones were fitted like THAT /so we fit the new ones like THAT.

Jac Mac

 

[Russ Noble]

Yeah, momentary brain fade!

 

[Russ Noble]

Hmmm.....

That's interesting, we've just had Speed220mph who has had experience with original cars in the day state that at the time they were fitted LHT/RHS. Which tends to go against the logic and physics that we have been discussing.

Post #17 here http://www.gt40s.com/forum/gt40-tech-chassis-brakes-tires-wheels/23836-braake-caliper-placement.html

Round one to the wire wheel brigade!

Cheers,

 

[Iain]

My only input to this highly erudite engineering discussion is that we have a pin drive / Central nut / Triwing system on the Cobra that has "forewards for off"on both sides. It has had 7 years of racing and we have never had a wheel come off. How hard do you hit the Tri wing ? .... no idea, but you can tell by the noise the assembly makes as it tightens up, it sort of turns from a dull thud to a "ping", see I told you I had limitless technical ability ! I will post a picture of the Triwing soon, it has aquired a fair amount of "patina" over the years

Iain

 

[Tim Kay]

As for a tool, click on the link below for this topic early on:

http://www.gt40s.com/forum/race-track/12720-trick-ko-tool.html

I ordered one of these the minute I layed eyes on it. It works fantastic.