Did the poms get the threads on wrong side?

It seems that if the splines strip under braking, the spinners will undo .

Braking forces are far stronger than acceleration forces, so in the english engineering idea, they have protected the two rear wheels for not falling off under acceleration.

If the spinners and hubs were swapped left side for right side, the car would be much safer.

Is it better to have a rear wheel fall off while accelerating or a front wheel fall off under braking?

I have heard about the "self tighten as drive" and the "tow an MGB backwards and the wheels will fall off".

Hard to believe.

Has anyone got any factual evidence?

Pooch

no hard evidence, but my take is as follows

you spend a lot more time accelerating than braking. I doubt that braking time would be long enough to loosen the nuts.

spline strip probably does not come into it as any wheelspin due to slip again would not last long enough under the sort of braking distance affected to cause the nut to loosen or undo

remember we are talking about little changes over loooong distances???

Henryk

Let me put it this way.

Even TOWING a car backward will loosen the spinners. There is enough mass to them to create enough inertia to do that even when there is no power being applied. I have seen it MANY times.

I have never had the guts or inclination to swap sides when installing the hubs and spinners but I suspect that you wouldn't get more than five miles without losing something really important. :-)

Chrysler, among others, use to have left hand threads on their LUG NUTS on the right side. The mass of a lug nut is pretty small so that might tell you something.

Most of the holding forces on the wires wheels are through the contact of the chamfered surfaces on the hub and inside the spinner, not thorugh the splines. There have been several threads addressing this in the past, but the idea is to get the spinners very snug and then let the natural inertia forces take over and tighten things up to the proper extent. Sitting there whamming on the spinner with a big hammer is detrimental to the shape and conformity of the outer flange surface of the wheel and can ruin one pretty quickly.

Jack

Suspect.

I am looking for factual.

Can't get any more "factual" than having personaly seen the wheels about to fall off as the tow trucks brought the cars into the shop parking lot with j-hooks and chains holding the rear wheels of the ground.

Other...I have read on more than a few sites for several different makes of cars that the information offered about the centering and security of the wheel being mostly due to the chamfering is true. Can't "factualise" that because I am not an engineer. :-)

All I can say is that what I have offered is based on first hand experience and several decades of reading. ;-)

Jack

I would imagine that having a wheel come off while at high speed or while accelerating to high speed would be a slightly bigger issue than if it occurred whist braking when your energy vector is decreasing. Granted that neither situation is a good one but if I had to pick a time for a wheel to come off it would be while I'm in the process of slowing. This is rather like picking fly sh-- out of the pepper, but again if I had to choose I would have made the same decision. Just my $.02.

No, they are correct - and it has little to do with acceleration and deceleration. The FACT is you spend a lot more time going forwards than backwards - and as Jack pointed out, if you tow the car backwards, the spinners WILL get loose. Even trucks have LH threads on the right side lug-nuts as they have enough mass to see the effect - cars typically don't do it because the lug nuts are relatively light - but if you own a Rolls Royce...

The spinner is ALWAYS trying to slow down - so, even at constant speed, the spinner will slowly tighten. However - if there was no friction between the spinner, threads and wheel, and the system was operating in a vacuum - the nut would only tighten during acceleration, and it would loosen during deceleration. Unfortunately, we have things like friction, gravity and wind resistance to deal with that all come into the equation.

Watch them change wheels on an F1 or an indy car - they use the same system (with "dog" drives instead of splines), but notice how the nuts are much more difficult to remove than install - and those cars see much greater braking forces than an MG will ever see. Or watch an old movie of LeMans - where they did use splined wire wheels - and watch how they have to pound on the spinners to get them off.

Bottom line is - the spinner should always tighten if held still and the wheel turned in the forward direction. If you don't believe it, swap your hubs side-to-side and see how far you get before the wheels fall off - it won't be very far!

Earl, I would feel better to have my wheel come loose on acceleration than in braking. If in acceleration mode the car just sort of slows down, if it happens to a rear wheel.

If it happens during braking, what ever wheel is in trouble looses its brakes almost instantly. Catastrophic would be my word for it. LOL

Jack

Factual evidence.

I worked at a scrapyard that specialized in British sports cars during the 80s. Selling replacement wire wheels, hubs and rotors to towing companies was quite common. A number of tow truck operators in our area learned the hard way not to tow wire wheel cars backwards. It was prevalent enough, that we could tell it was a tow company ordering parts just from the list they gave.

kelvin

Jack,

I was thinking strictly in terms of energy states. I was thinking that I would sooner have it happen as I was decelerating through 20 MPH than accelerating through 60 MPH. In either case it's an undesirable situation, but the slower the speed at which something bad happens, the better. I realise there's more to this situation than what I've mentioned but that's what I was thinking.

I had a MK I MGB with a stripped spline on one of the rear wheels. It was nearly impossible to get the knock off loosened when trying to take that particular wheel off. As I recall, I had to resort to a 4 pound sledge get ti loose.
Cheers,

Did the poms get the threads on wrong side?

Nope, It only seems that way to them that's upside down :D

I haven't a clue about the whys & wherefores but it's been the way it is for a bloody long time and worked fine all that time.

If the splines strip on a wheel or hub, your biggest problem is going to be lack of braking effort on that wheel, rather than the spinner coming loose.

Moss motors had a write up about a TR3 owner who installed the hubs in reverse. He had just restored the car for a Moss Motors show in CA. Enroute his knock on came off. It was printed and documented.
Don't muck with 100 year old known technology IMHO.

Looks like everything has been covered rather thoroughly, but I will throw in one more personal observation. I have met more than one person who had hubs installed backwards and suffered "sudden wheel departures". It is indeed fact that they can come off if installed the wrong way around!

Yup. 40 years ago a guy I know had a C-Sports Racing (formerly CM) special than was on an old Jag chassis. San Francisco Region Regional at Sears Point. He crashed it in Fri practice and did an all night thrash to fix it. Showed up, off the trailer, onto the track. First turn, 3 of the 4 wheels came off. Opps! He'd assembled the suspension units backwards...left onto right. Crazy Phil we called him. Anotehr all nighter had the car on the grid and assuming it's usual second-from-last in a 5-car field on Sunday.

If that's not enough "factual evidence" for ya, then you could always swap your hubs side to side, and get first hand "factual evidence" for yourself when the wheels come off. (but I don't recomend it)

Please have your next of kin forward appropriate documentary evidence. : )

The way the knock off contacts the wheel determines which way it undoes. Lotus Elans & GT40's for example have the knock offs opposite to the Rudge type hubs, as they are of the "male" style nut, while the Rudge knock offs are the "female" type nut. Chunky Chapman had a simple demo with a roll of tape and another cylindrical object of smaller diameter. If you place the smaller cylindrical object inside the roll of tape on a flat surface and move the smaller one in a clockwise circular movement (not rotated) the roll of tape will turn clockwise as well. But if you move the tape clockwise, the smaller cylinder will move anticlockwise. The Rudge style knock off is represented with the first set of movements, the "Male" nut is the second set.

Well, Here is a fact. Some years ago I was coming out of the mountain in my 69 that had wire wheels. Approaching a 90 degree turn onto a one lane bridge, I was braking hard. My right front wheel splines sheared and off came the wheel. It came down on the brake rotor, and I got it stopped without falling into the river. My brother was following me and saw where the hubcap nut went. We put the spare on and tightened the nut real tight. We then spent the next 45 minutes looking for the wheel. It rolled up a hill then back nown into a bush. The rest of the trip home was with the parking brake. It taught me to inspect the splines regularly and keep them greased. Never had one shear under acceleration.
Bruce