KH Knock-off Adapter Thread Lube?

[James W.]

I finally got my original KH knock-off wheels off of my '65 last night. I used an 8 pound lead hammer and had a hard time getting them to come loose. Once they were off I looked at the adapter treads which had quit a lot of rust on them. I plan to wire brush the adapter threads before reinstalling the wheels. My question is has anyone used Pre-Lube 6, WD40, a thin coat of Never-Seize or high temp synthetic grease to keep them from rusting and make it not so difficult to get them off next time?

Thanks,

James

[Russ S.]

Re: KH Knock-off Adapter Thread Lube?

I used never seize which worked well.

[Jim D.]

Re: KH Knock-off Adapter Thread Lube?

I, and all of my Cobra buddies, use this on our knock-offs with great success - https://www.southwestspeed.com/?sec=view_part&id=9188

[Michael G.]

Re: KH Knock-off Adapter Thread Lube?

I've never heard whether these attachments had any sort of lubricant on them when they left St. Louis, but if the adaptor threads were cadmium coated, as I've heard, that would have a huge impact on the tightening process. Cad is really slippery stuff, and its use would mean that additional lubricants and/or anti-seize were initially unnecessary.

That, of course, doesn't mean much 50 years later (today), as most of these things (adaptors) are very rusty, or they've been re-plated, likely with something other than cadmium. Not knowing exactly what plating is on you adaptor threads is scary. If the threads are rusty, or re-plated with zinc, you probably need anti-seize. If they're cad plated, with no rust, you don't. I wouldn't use another lubricant, unless you know what platings your dealing with. Putting lube on freshly plated cadmium will really create a lot of unexpected clamp-load, but is likely a sure way to make sure they vibrate loose.

Given that you probably don't know what's on them, I'd use anti-seize, and retighten them after a few miles of initial installation, then periodically thereafter, as matter of self-defense. Keep checking 'em and you'll be safe.

I hope that helps.

[Richard G.]

Re: KH Knock-off Adapter Thread Lube?

Check this out:
Corvette America's instructions on the wheel installation;
http://repairs.willcoxcorvette.com/w...structions.pdf

[Alan D.]

little paranoid. (Other experts on these are just fine with the GM method)

Good luck with them.
Alan

[James W.]

Re: KH Knock-off Adapter Thread Lube?

Thanks to all who replied. I cleaned the treads on the adapters and the spinners with a wire brush and applied a light coat of nuclear grade never-seize to the adapter threads. Why nuclear grade, it's what I had in the garage. I reinstalled the wheels taking note of my match marks on the center cone and the spinner and hammered them back on to the same "tight" match marks. Drove about 50 miles and rechecked them and found no movement.


Thanks,

James

[Bill C.]

Re: KH Knock-off Adapter Thread Lube?

James, K/O wheels are held on by clamping force between the conical seating area of the spinner and the wheel ... NOT thread friction. To install them properly, you do need to lube the threads with a bit of anti-seize (as you did) and ALSO the conical mating surface in order to get full clamping force. If you put the spinners on dry threads and dry cone seats, this will create friction/dry-galling of the threads which will lead you to believe you've got them on tight, but in fact they are not. The required torque is around 450 lbs, which is also why you need a BIG lead hammer and many blows to develop this clamping force. When you think you've got it, mark the spinners with a black Sharpie or 1/4" tape, drive around the block a few times with tight cornering and recheck your marks. If any moved, resume pounding with your big hammer. Once they are on properly with the required torque, they won't come off on their own. Bill

[Richard G.]

Re: KH Knock-off Adapter Thread Lube?

GM's torque specification of 450 lb/ft is ambiguous without the thread lube type / or dry specification.
Example - Reduction of Torque when Bolt is Lubricated;
The maximum tightening torque for a slightly lubricated 1" grade 5 course threaded bolt is 483 lb ft. Dry bolt torque is approximately 30% higher - or 628 lb ft.

If I did agree to lube the threaded portion it would likely be with oil. As Graphite or anti-seize both reduce the torque required to tighten the bolt by the highest percentage when compared to other types thread lubrication. I would not apply any to the clamped faces. Just my take on it. Seems prudence in inspecting for looseness an marking for possible changes in the clocked position would be prudent and wise. It is easy to understand why modern replacement knock offs include a locking pin for safety reasons.

[Bill C.]

Re: KH Knock-off Adapter Thread Lube?

Richard, I agree the GM torque spec is ambiguous for sure. A lot of these K/O wheels have come off over the decades, and I would suggest it is always because they were not properly installed ... most likely because of lack of understanding. I think there are 3 primary issues that resulted in failure:

1. Adapters installed on the wrong side of the car (ie: RH thread on the RH side). I've seen it myself several times. This happens when tire shops or individuals are changing/rotating tires and they (nor the owner) don't really understand what keeps these wheels on.

2. Not using the GM designed long lug nuts to hold the adapters on. While the standard short ones will work, they can also allow the wheel to go on without the adapter drive pins engaged in the correct holes. The long nuts where specified to prevent this error.

3. I believe most often they have come off due to lack of adequate torque. I suspect this is primarily due to not lubricating the adapter threads in particular resulting in dry-galling and the installer thinking they are torqued on tight when really they are not. I think its common sense the weight needs to be off the wheel in order to get the wheel/adapter conical surface mated correctly at the beginning of the tightening process.

The pin feature was added really as an anti-theft device, not a safety one. Aluminum pins WILL NOT stop a spinner from backing off for any of the 3 reasons above. The forces working on that wheel/adapter/spinner nut is just too great. If people think they will, I'd highly recommend they start shopping for new fenders now as they will need them sooner or later. They are used simply to make it more difficult for a thief to hammer those spinners off.

Everyone with K/O wheels (with adapter pins or not) should be in the habit of marking their spinners and checking these marks occasionally (frequently after re-installing) to ensure they are not backing off. Other makers have holes for wires to do the same thing. That's my recommendation. Cheers, Bill

[Terry M.]

Re: KH Knock-off Adapter Thread Lube?

There was a story about tightening quick take off wheels in The Restorer when I was Editor -- sometime between 1999 and 2005. IIRC Bill Sangry was the author. We found a BFH that would do the job better than the lead hammer, and with less damage to the hammer or spinner.

[Michael G.]

Re: KH Knock-off Adapter Thread Lube?

James, K/O wheels are held on by clamping force between the conical seating area of the spinner and the wheel ... NOT thread friction. To install them properly, you do need to lube the threads with a bit of anti-seize (as you did) and ALSO the conical mating surface in order to get full clamping force. If you put the spinners on dry threads and dry cone seats, this will create friction/dry-galling of the threads which will lead you to believe you've got them on tight, but in fact they are not. The required torque is around 450 lbs, which is also why you need a BIG lead hammer and many blows to develop this clamping force. When you think you've got it, mark the spinners with a black Sharpie or 1/4" tape, drive around the block a few times with tight cornering and recheck your marks. If any moved, resume pounding with your big hammer. Once they are on properly with the required torque, they won't come off on their own. Bill

Bill, What do you think creates the clamping force between the conical seating areas?

That force is generated by the mechanical advantage from the tightening of the threads. The relationship between the torque applied to the spinner (however you choose to apply it) and the actual clamping-force created between the cones is directly related to the friction that occurs on the thread surfaces, combined with the friction that the two cones see on their mating surfaces.

The all-important determinants of that clamp-load is thread friction and cone surface friction, nothing else. Assuming identical application of torque to two spinners, one with lots of friction on the threads and cones, the other with very little, the high friction wheel will see lower clamp load, but with lots of resistance to vibrational loosening. In the other similar spinner, with little friction on the thread and cones, lots of clamp load is delivered, but resistance to vibrational loosening is low. Thread friction is therefore critical.

Your terms are incorrect. High friction is not "galling", though "galling" may result from extremely high friction. Galling of threads is the destruction and/or tearing of metal on the threaded surface, resulting from extreme friction between those male and female surfaces. It is not the normal sliding frictional relationship between them, it is an abnormal event that results from excess friction causing the two surfaces to seize rather than slide. That seizing is relieved only when the base metal actually tears before the sliding can occur on its surface. It is abrasion, not frictional sliding, nor is it something you want to happen in any fastened joint.

[Bill C.]

Re: KH Knock-off Adapter Thread Lube?

Mike, I agree with your comments. I said that wrong in the beginning as I thought the OP was commenting about the "rotational friction" of the threads because of heavy rusting. I do agree the conical clamping force is indeed generated by thread friction as the spinner nut is tightened.

I think the key points have all been covered for folks installing traditional k/o wheels (not bolt-on look-alikes) so they can be sure they won't come off on their own. Bill

[Michael G.]

Re: KH Knock-off Adapter Thread Lube?

Thanks, Bill.

The problem with trying to give advice on these wheels today is that the current owner usually doesn't have any idea what's been done to the wheels and adaptors (in the way of "restoration") over the last 50 years. Rust, polishing, restoration, and/or re-plating of the adaptors can make all the difference in friction, therefore, the soundness of the attachment.

Contrary to what's suggested in many posts here, 1964-66 installations instructions, and/or 50 years of experience, may not apply, because the parts have worn, been re-plated, or the bearing surfaces have been re-cut, or worse. The best you can do, to be safe, (unless you know you have unaltered, non-corroded, parts) is to tighten them to the old instructions, check them after a few miles, then constantly monitor their tightness.