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Knock-off wheel removal


Matt Harwood

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Just when you think you know how things work, things change. I have a fairly high-end Cobra replica with knock-off Halibrands, and we need to change the tires. The Cobra manufacturer went out of business about 30 years ago, so I can't call them and there is no manual with the car. This car uses what appear to be Jaguar E-Type suspension components, including the independent rear end and, I presume, the threaded hubs. It has three-arm knock off nuts threaded onto the center hub which are designed to be hit with a hammer. These were also safety-wired in place, which is the correct way to do it.

 

Anyway, which way to I hit them to remove them? I can find no conclusive advice elsewhere on the internet, because every thread on every possible type of car wearing knock-offs from the aforementioned E-Type to the Cobra replica boards seems to disagree on the direction. In almost every single thread, a majority says that you tighten towards the rear, which would make the right side threads opposite (tighten in counter-clockwise motion). But my gut says that like my '29 Cadillac and many '50s and '60s Chryslers, the driver's side of the car (left) would have left-hand threads that would go in the opposite direction--that way, the motion of the wheel will tend to tighten the nut, yes? Information on the internet goes about 70/30 in favor of the right side hubs being opposite and left side hubs being conventional.

 

To make things more confusing, by running my fingernail in the exposed threads on the hub, the driver's side seems to be opposite--turn counter-clockwise to tighten. As I move my fingernail around the threads in a counter-clockwise direction, it moves deeper down the threaded hub.

 

I don't know what to believe, including my own eyes and my own intuition. I even tried building a tool that would fit over the hub and grab the ears and would have a long T-handle that two of us could pull, and that won't even budge the hub nut.

 

My problem is that someone hammered these on so tightly that hitting them in either direction does nothing. Before I break out some serious force to start moving that sucker, I need to know which way to turn it. I don't trust my own eyes or the information I'm reading, and I'm stuck. This is stupid, but I don't want to damage the thing.

 

Any thoughts? I'm exhausted.

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Edited by Matt Harwood (see edit history)
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Use what we called a  lead hammer (not sure if they are actually lead but all my MG’s and my Healey with knock offs had them) not a carpenter type steel hammer. You will see marks in the hammer that way and not destroy the knock offs 

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Lead hammer is the way most remove the knock offs. As far as direction, unless you can see the thread and tell for sure, you are going to have to hammer one until it moves. Most real knock offs tighten, the way the wheel rotates. I don't know about the replica ones. In other words, tighten in the direction that the wheel rotates. This always makes sure the KO will stay on, and will try to tighten itself if it is loose. 

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Thanks for all the advice guys. I called a Cobra specialist who makes a tool just for this purpose and talked to them for about a half-hour. Sadly, they couldn't really answer the question about which way it turns or even which way it is supposed to turn. It was just like every other thread on the internet--he SAID turning the nut towards the back of the car tightens it (left uses right and right uses left is how he put it). But then he went into a long description of how the threads are designed so that the motion of the wheels tightens the nut, which would imply that turning it in the direction of travel (towards the front of the car) is correct. I don't know. I'm going to just go with my fingernail test and assume that those on the left side of the car are left-hand threads and those on the right side of the car are right-hand threads. 

 

He also said that the guys assembling the Cobras, even the factory-made ones, sometimes got the wrong parts on the wrong side and it didn't work like it was supposed to. This one was built in the '80s, so who knows who did what.

 

Ultimately I spent the $300 or so and bought the tool and a proper 6-pound lead hammer that he recommended. The tool should pull on the spinner gently and I should be able to determine if it's moving in the right direction in pretty short order and change directions if it seems to be locked up. This is apparently a very common problem, particularly on cars that don't get driven a lot. I watched a few videos and broken ears on the spinners are VERY common in the Cobra world as guys bash on them with increasingly large steel hammers. I was using a 45-ounce dead-blow hammer, which hits pretty hard but won't mar the surfaces. However, it doesn't have the same properties as lead and he said it would never knock it loose no matter how long and hard I hit it. It apparently needs a little bit of a metal-on-metal hit to set up a "shock wave" through the threads to vibrate the nut loose. I guess that kinda makes sense in an obtuse way...

 

img126.gif

 

So I'll have the right tool here on Wednesday and we'll see if it works. I'll report back and let you know how it goes.

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Matt, trust your fingernail for direction and don't be timid about changing directions every couple of whacks with the hammer until you get something that resembles movement. Even anti seize doesn't last forever and if the tires are old enough to have come with the car getting the spinners off could be the easy part.

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You can't confuse lug nuts with knock-offs because the physics is different. Yes, for lug nuts the left side uses left hand threads. But that is because of the "Coriolis effect" or force, which does not apply in the knock-off case. The reason the Coriolis force comes into play with lug nuts is that the center of mass of the lug nut is some distance (radius) away from the axle which is the axis of rotation. That is not the case for the knock-off, where the center of the knock-off and the axle axis of rotation coincide.

 

Left hand threads for the right side knock-off makes sense, because if you think of a moving car scraping against say a wall the friction force would tend to tighten it, the friction would be in the opposite direction of wheel rotation, so if the threads on the right side were left hand that would tighten it. In other words I think they chose the thread direction so that an accidental impact with a stationary object would be more likely to tighten it, not knock it loose.

 

 

Edited by mike6024 (see edit history)
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All I know is that after (stupidly) replacing the right front hub on my MGA roadster with a left front hub, it unscrewed itself and the wheel went out the front fender between the door and the fender.

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Isn't the principle in play the one where a smaller diameter rotating inside a larger diameter has a net rotation in the opposite direction?  Then as Spinneyhill pointed out the direction depends on the style of locking taper and that is why you get two different answers.  Once you confirm internal or external taper, you will get consistent answers.  MG and Jaguar are external.

 

Sorry it was 1937hd45.

Edited by emjay (see edit history)
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There is a discussion on the HAMB site about this very subject. Fellow with a hot rod '32 roadster, driving down the road and his left rear tire and wheel passed him by and he was scrapping the pavement. The consensus  is that by hitting the front of the KO (towards the front of the car) tightens the KO. ONLY if it is real, not an aftermarket fake.

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Matt,  if you were referring to A.C. Cars limited when you said the manufacturer of the Cobra was out of business, that is incorrect.  They are still in business and still make the Cobra and other models on a very limited (read handbuilt) basis.  Their website is www.accars.eu.

 

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Thank you for all the feedback, everyone. I have confirmed that this particular Cobra has left-hand threads on the left side of the car and right-hand threads on the right side of the car. That seems intuitive to me, since the rotation of the wheel is in the direction of tightening the hub nut, but it is contrary to about 70% of the opinions I've read, most of which say that knock-offs (particularly Jaguar E-Type, which these actually are) should tighten towards the rear of the car. That's why my Cobra expert said left is right and right is left. On this car, anyway, left is left, right is right. The fingernail test confirmed which way we should turn so we went at it. 

 

I should also note that the tool above worked like a dream. Putting some tension on the spinner and then giving it a couple of whacks with the lead hammer I bought with it, and it started to turn immediately. We had both wheels off in less than 10 minutes. There's a HUGE amount of anti-size smeared all over the threads and hubs, so we're going to clean all that off and just use some light oil on the threads when we're reassembling it. My Cobra guy also said that the spinners should not be much tighter than you can pound them with your fist--no need to really hammer them into place, especially since we'll be using safety wire to secure them. Snug is good, and the safety wire will keep it from backing off. The safety wire is also good because you can see if it is moving--the manual for the E-Type sitting in our showroom says to give the hubs a whack with the mallet every few drives. But hitting them every few days whether they need it or not, well, it's easy to understand how they could get over-tightened.

 

Thank you for the advice, but this was yet another situation where the solution was simply having the right tools for the job. I spent $300, but I suspect this won't be the last Cobra I have with knock-off hubs so it should be useful again in the future.

 

 

Knockoff2.jpg

Knockoff1.jpg

 

 

 

Edited by Matt Harwood (see edit history)
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Matt, Thanks for the report on that tool, never seen one before and didn't know anything like it existed. I googled the tool, watched the video and printed the page for my Jaguar hoarding, outside under tarp storing friend. So much better than pounding on the spinners until they move, or freezing the hub with dry ice, or heating the spinners and hoping they don't break before they move.

 

Loved the silvery sloppy picture of the hub,. Might not be enough anti seize for an alloy wheel that's going to run in road salt for years between tire changes, but overkill for the way this car will be used. Sometimes you should use anti seize like it's free, most of the time you use it like Brylcreem as a little dab will do ya.

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Why use oil when you had such a good experience with anti-seize ?  You know the anti-seize works, you don’t have to put as much on. I would think the oil could get dirty or dry up some and cause problems.

just a thought no real knowledge on my part. 

Dave S 

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On 6/18/2018 at 2:01 PM, Matt Harwood said:

 I have a fairly high-end Cobra replica with knock-off Halibrands, and we need to change the tires. 

 

1 hour ago, 1937hd45 said:

Do REAL COBRAS have Jag rear ends or is this a repop? Bob 

 

Answered in the first line of the original post!

 

Also, Mercedes-Benz incorporated very clear instructions on the 300 SL Rudge hubs:

Mille-Miglia-2016-mechtel-4-960x539.jpg

Edited by ejboyd5 (see edit history)
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12 minutes ago, SC38DLS said:

Why use oil when you had such a good experience with anti-seize ?  You know the anti-seize works, you don’t have to put as much on. I would think the oil could get dirty or dry up some and cause problems.

just a thought no real knowledge on my part. 

Dave S 

 

The anti-seize was part of the problem. It was like glue holding the spinner tight, especially with years of grit working on it. It was also holding the wheel on the hub even after we removed the spinner and we had to pound it off with the dead-blow hammer. All the sources I've spoken to or read say no to anti-seize on knock-offs, just some light oil on the threads so the spinner can be torqued smoothly. You don't need to really make them tight, just snug. The Cobra guy said it should be as tight as you can make it by pounding on it with your fist. The safety wire is what actually keeps it in place and snug, not friction. Anti-seize at that point is not helpful.

 

 

 

Edited by Matt Harwood (see edit history)
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1 hour ago, 1937hd45 said:

Do REAL COBRAS have Jag rear ends or is this a repop? Bob 

 

Having some Salisbury in my family tree, I can assure you that the first Cobra got reworked with a Salisbury rear end, the same rear end used in the Jag.  

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16 minutes ago, Matt Harwood said:

 

The anti-seize was part of the problem. It was like glue holding the spinner tight, especially with years of grit working on it. It was also holding the wheel on the hub even after we removed the spinner and we had to pound it off with the dead-blow hammer. All the sources I've spoken to or read say no to anti-seize on knock-offs, just some light oil on the threads so the spinner can be torqued smoothly. You don't need to really make them tight, just snug. The Cobra guy said it should be as tight as you can make it by pounding on it with your fist. The safety wire is what actually keeps it in place and snug, not friction. Anti-seize at that point is not helpful.

 

 

 

Even anti seize doesn't last forever and if you can pound the wheel off with a dead blow hammer it's not really stuck. Oil is for the owner that is meticulous about proper maintenance, anti seize is for the rest of the world. I would say go with oil as that is what the true enthusiast is going to expect and if the buyer doesn't check the safety wire to make sure you have the right number of twists and tension, better tell them that the spinners are on with oil and that they need to be redone every year.

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Put a little thought into the marking of the rotation. There is a story about a very attractive, but unbadged,  sports car parked on a city street. Passers by were beginning to crowd around the car, speculating of what marque it might be when a voice low in the group squealed "It's an Undo!"

Bernie

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10 minutes ago, Vila said:

Here is a very recent posting on the Triumph Experience website had to say about knock off direction, "Think Opposite".   Meaning LH threads on Right and RH threads on the Left.

 

I would read the following posting: https://www.triumphexp.com/phorum/read.php?7,1540079

 

Even that thread is saying two completely different things and is far from definitive. On the one hand, the guys are saying left-hand threads on the right side of the car and right-hand threads on the left side of the car is the correct way to do it.

 

BUT! They also point out that driving the car should tighten the hubs which suggests that left-hand threads on the left side of the car and right-hand threads on the right side of the car, such as on my Cobra here. It can't be both ways. Either you tighten in the direction of rotation so that a forward-turning wheel tends to tighten the hub, or they're reversed where they turn in the opposite direction. It can't be both. If the hubs are tightened by going in the direction of wheel rotation, then you will have left-hand threads on the left side of the car. 

 

This is why it was so frustrating because people aren't thinking at all about what they're saying. They think one thing and believe the reasoning is correct, but in the real world, they don't agree. Right-hand threads on the left side of the car will loosen themselves if turned in the direction of forward wheel rotation (counter-clockwise). The same is true of left-hand threads on the right side of the car. Now whether the hubs will actually loosen themselves as you drive is another discussion, but if the theory is that the motion of the wheel will tighten the hub, then it can only be left-left, right-right.

 

Of course, I also understand that different manufacturers could do it different ways, but as I learned, the only way to know for sure is to take it apart and see which way the threads go. Everything else is just maddening speculation and guesswork.

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33 minutes ago, Matt Harwood said:

Everything else is just maddening speculation and guesswork.

 

That's what I told the small business administration when they asked me for a business plan 12 years ago.

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34 minutes ago, Matt Harwood said:

 

 

 

This is why it was so frustrating because people aren't thinking at all about what they're saying. They think one thing and believe the reasoning is correct, but in the real world, they don't agree. Right-hand threads on the left side of the car will loosen themselves if turned in the direction of forward wheel rotation (counter-clockwise). The same is true of left-hand threads on the right side of the car. Now whether the hubs will actually loosen themselves as you drive is another discussion, but if the theory is that the motion of the wheel will tighten the hub, then it can only be left-left, right-right.

 

Of course, I also understand that different manufacturers could do it different ways, but as I learned, the only way to know for sure is to take it apart and see which way the threads go. Everything else is just maddening speculation and guesswork.

This is why knowing if the taper is an inner or outer is so important. Bob 

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5 minutes ago, mike6024 said:

 

You're not understanding something there.

 

 

 

To my thinking, left-hand threads on the right side of the car will tighten counter-clockwise (AKA towards the back of the car). However, when the car is travelling forward, the wheel is turning clockwise, which is the direction that will loosen the hub. There seems to be a significant number of people who say that the hubs should tighten towards the rear of the car and I'm even seeing several videos that show cars with that as the situation. Obviously there's a reason, even though the guy who built this particular car didn't seem to subscribe to that way of thinking.

 

I don't particularly care one way or the other now that I've got this particular car figured out, but why is the proper direction to tighten a knock-off wheel  the direction that will make it loosen as the wheel turns? Why did engineers at GM and Chrysler fear for decades that lug nuts would loosen themselves if they used right-hand threads on the left side of the car? Why is this Cobra wrong even though the spinners were locked down so solidly as to need a $300 tool to remove them?

 

What am I not understanding?

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Yes there is no reason to care at this point since it's been figured out. But the point is when a wheel and the associated spinner is rotating as it is traveling down the road at a constant rpm, there is no net torque of one relative to the other. They both have angular momentum in the same direction. So there should be no tendency to either tighten or loosen regardless of whether the threads are left or right or which side of the car they are on. Constant rpm, angular momentum, they continue to rotate at the same rate and the spinner and wheel at the same rate. It is the rotational equivalent of the Newton's law, "A body in motion will tend to stay in motion."

 

It is when you have either friction or angular acceleration that a torque of one relative to the other (spinner relative to wheel) can be developed. For instance if the brakes were slammed on locking the wheel, the wheel would stop rotating, but the spinner due to it's angular momentum would be inclined to want to continue rotating, and this tendency would put a torque on the spinner relative to the wheel, so it would tighten or loosen depending on the thread direction.

 

Or if you hit the gas, spin the rear wheels, the spinner will want to stay stationary due to it's "rotational inertia", not rotate. So it will want to tighten or loosen depending on the thread direction. A body at rest tends to stay at rest. As anther example : if I try to loosen a tight crankshaft pulley nut with a ratchet and a socket, I will just turn the whole engine over as the nut, pulley, and crankshaft all turn. But if you hit the nut with an impact gun it will come off, because the rotational inertia of the crankshaft will not let respond to the high angular acceleration the impact gun can deliver, so you get a torque of one relative to the other, nut relative to crankshaft.

 

No traveling down the road at a constant speed should not tend to tighten or loosen the spinner no matter which side or thread direction.

 

Just trying to clarify the physics of it.

 

And why lug nuts on the left side had left thread is very difficult to understand, truly understand the physics of. One needs to study and understand rotational dynamics, vectors, angular acceleration, the Coriolis effect and all that to truly understand where that came from. But in fact the Coriolis effect is so small that it doesn't much matter anyway, and using right hand threads on the left for lug nuts is OK.

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