Matt Harwood

Knock-off wheel removal

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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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I would imagine it would be right on right and left on left as most race cars were set up that way.

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Maybe you can look up Halibrands to see if they sold sets for Cobras and if they were R & L threaded?

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I would go by the fingernail test. Even if we know how they are supposed to go on there is no guarantee they were put on properly. I also like the idea of making a long wrench rather than beating on them with a hammer.

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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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So you put a right-hand thread knock-off hub on the right front side. Hmmm... under ordinary circumstances that should stay put anyway, even though it is wrong. At least we're thinking that is wrong at this point.

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image.png.fe74cf80e09a596f7663d1dbd9b74011.pngThat is what I call an inner taper on the knockoff, same as a 1930's Dayton dirt track race car wire wheel. They come off opposite the common Rudge Whitworth wire wheel. Bob 

 

 

 

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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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A little heat might help.

Especially handy on dissimilar metals.

Might not be correct but I use it all the time on stuck stuff.

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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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