Wheel: what Tightening torque

[chrisfell]

The self tightening spinner story is an urban myth and a dangerous one at that.

[mark10337]

Have a look at Dave's video on youtube

If you look at the spinners, they loosen in the same direction as the forward motion of the car. It is the braking forces that would cause tightening (if any).

[angelw]

Mark Wrote:

If you look at the spinners, they loosen in the same direction as the forward motion of the car. It is the braking forces that would cause tightening (if any).

Hello Mark,
What forces do you believe are in play to have the Knock On Nuts tighten during braking?

Lets say that there is excessive clearance between the hub and wheel splines allowing the wheel to rotate relative to the hub. In this case, under braking, relative to the hub, there would be a tendency for the wheels to rotate in the direction of rotation corresponding with forward motion. This would have a tendency to loosen the Knock On Nuts.

It would seem that the most relevant force relating to the Knock On Nuts tightening/loosening is inertia. When braking, Knock On Nuts would want to stay rotating and therefore, relative to the wheel and hub, try and rotate at a faster rate than the hub and wheel; again, a tendency for the nut to loosen under braking.

The inverse would tend to happen under acceleration, particularly with the rear wheels. The rear wheels are being driven by the hubs, whereas the front hubs are driven by the wheels.

In all cases, any tendency for the Knock On Nuts to either tighten, or loosen and would need to exceed the torque used to tighten the Nuts for it to actually happen.

Regards,

Bill

[Heuer]

I found this explanation of the way the Rudge Whitworth hub works but I am no wiser as to whether it actually tightens, remains were it was set or does not self-loosen. And if it does tighten, how much torque can be applied in this manner:

"In its essentials the Rudge-Whitworth wheel comprised three key components: a splined hub and two pairs of matching tapers (conical surfaces), one comprising the inboard end of the hub and the inboard wheel centre, and the second the retaining nut and outboard wheel centre. These tapers served three functions. First, they automatically centred the wheel on the hub. Second, they transmitted a significant fraction of the drive and/or braking torque so as to reduce the load on the hub splines. And third, they made the wheel-retaining nut self-tightening. Imagine that the nut loosens slightly so that the tapers on the wheel and nut touch at only one point on their circumferences. Because the male taper is now of smaller effective diameter than the female taper, rotation of the wheel on the hub under braking will cause the nut to rotate on its thread. If this rotation is in the correct direction — which is ensured by using differently handed threads on either side of the car— then the nut will automatically re-tighten itself."



This is from the Rudge Whitworth article which explains the system as "self-locking" - the cone centres the wheel and the spinner self tightens but requires a spanner or hammer to get it to that position. I think that is possibly where the confusion comes from - the spinner does indeed self tighten but only does so when whacked with a hammer:


Also if the system is self tightening just how does the spinner come loose so it can self tighten again?

Interestingly, and something I did not know, after Rudge Whitworth went bust in 1936 Jaguar acquired the rights to Rudge's wheel business and together with Dunlop continued to exploit the design for both wire and disc wheels although by then the system was termed 'fail-safe' rather than self-tightening.

[1954Etype]

Really interesting. All I will say is that if spinners have been left on a car for a few thousand miles, they can be really difficult to shift. I always loosen and refit mine after long journeys.

I'm not saying they self tighten just that they seem harder to remove.....

[Heuer]

Don't think it has anything to do with continued self tightening because once the tapers lock they can't physically move further. Here is another explanation of the Rudge Whitworth hub which seems to confirm it:

In 1913 the Rudge Whitworth coned locking device was introduced. The parallel splines are a loose fit on the inner hub and a proportion of the car's weight is carried by the nut itself. The nut tightens on the male coned surface of the end of the outer hub, and has a mating female cone machined in it. If the nut is loose there will be a gap between these two cones, allowing the wheel to wobble slightly. The car weight will now be carried at a single line of contact between the coned surfaces of nut and wheel. As there is a gap between the cones, the effective diameter of the cone on the hub is smaller than that of the nut.

The line of contact therefore rolls relative to hub and nut as the car moves. This, the theory says, can be likened to an epicyclic gear. In this arrangement, with the planet gear (i.e. the outer hub) rotating, and the planet carrier fixed (i.e. in this case always vertical), the outer gear (i.e. the nut) will tend to rotate backwards. By placing left hand threads on one side of the car, and right hand threads on the other, this tendency is used to tighten up the nut. The weight is also carried by the threads at the bottom of the nut, and the relative motion between the nut and the inner hub induced at this point is in the same direction, and also adds to the tightening action. Once the nut has tightened, the clearance between the cones is taken up and the rolling action stops. (my underline)

So confident were Rudge Whitworth of this theory that one of their patents describes a nut in which ball bearings are added to enable it to tighten itself more easily. It was only necessary to fit the nut hand tight, and after 1/2 mile or so (forward) it would require a spanner to release it.The early Rudge tapered‑cone wheel nuts were circular, and were removed with a special spanner. I don't believe theories like this so I always knock my wheel nuts up tight, especially on the wheels with dodgy splines.The knock‑on ears did not appear until much later.

Here are the Dunlop official period instructions on the use of Dunlop Rudge Whitworth pattern hubs:


These confirm the wheels should be off the ground before the hammer is used and on no account should the car be run without the spinners fully tightened - "the lock nuts are designed for self locking".

[Gfhug]

The need for the wheel to be off the ground would seem to negate the use of the adapter with a torque wrench or long breaker bar to tighten the spinners as is shown in the original posting.

I've been happily using one of Lionel's adapters and breaker bar on my continental spinners and have always thought it did an ok job (except on the repro spinners)

Geoff

[E-by'eck]

Confusing!!! bought a set of repro spinners some time ago in readiness for when needed as still restoring the car. Was it a bad decision?? BUT surely many sets have been purchased and there hasn't been any significant reporting of wheels dropping off has there?? SNG Barrett etc wouldn't still be selling them would they??

Also reviewed my old spinners against Heure's "spot the repro" list. Not that easy. These two both have castings 1467RH AB and 1466LH AB. G&U look similar, but UNDO arrow on one is much shorter than the other. Both original? One Repro? Looks like a set of scales for any car boot purchases may be the only option if planning to seek out a set to restore.

Graham

[Heuer]

They are both original Albion-Brockhouse but from different time frames and dies. The dies wore out and as new ones were commissioned Jaguar would have the opportunity to make changes, hence the difference in the arrow. The number '3' on one of them suggests it was the third iteration of the die. I have a set of original NOS spinners and the Jaguar logo on two of them has slightly fatter characters.

The repro spinners will not fall off but there have been reports/cases of knocking sounds that have been traced to a repro spinner which cannot be tightened further.

[E-by'eck]

Thanks David...very helpful.
Graham

[mark10337]

I have terrible knocking on the front O/S with a repro continental spinner. However, this is only noticeable with the Dayton wheels. The Realm D-type wheels are ok.

Do you know if Julian Barratt is aware of this? Where should the repros be shaved exactly? In the U channel around the centre?

[Heuer]

The trouble is there are three components to the Rudge Whitworth system (hub, wheel and spinner) and any one of them, if reproduced poorly or out of original specification, can cause these problems. Some combinations are OK, others are not as you are finding out. My belief is the spinners are the main cause of trouble so I suggest you get hold of an original spinner (eared or continental) and compare the dimensions with a micrometer. My observations suggest the base of the spinner where the thread ends is not deep enough and contacts the hub stopping it being tightened further. You can see here that the repro spinner on the right has contacted the hub and there is a witness mark:


This spinner caused a knocking of the o/s front wheel on my FHC at full lock.

I think the U channel on the repro's is deeper than stock but bear in mind my research was done on eared spinners from Orson Engineering. Their continental spinners do at least have the correct logo! Julian is aware of the problem but you could always ask him if there has been any progress on getting the A-B ones made again.

[steve3.8]

To simplify finding out the error of the spinners dimensions use engineers blue [stuarts] on both the hub end and thread also the wheel taper, fit and remove the spinner then read the results inside the spinner .

Just to add a bit more to the tightening / loosening theory , Lotus spinners undo and tighten in the opposite direction to Jaguar , i can only reason that is because the male/female taper is also the opposite way around to Jaguar, ie lotus spinners have a male taper ...?

[mark10337]

Thanks. Thinking on it some more, I know that O/S hub has definitely been replaced in the last 2 years. The other's I'm uncertain of their history.

The aftermarket eared spinners have been off the car for over 2 years. Taking a look, I can definitely see the grease has not hit the end of the threads on the spinner.



Any alternatives to the Stuarts engineers blue. I'm not within easy reach of anything like that here - or places to get those sorts of products. Blue non-setting gasket sealant? Although I run the risk of looking like a smurf getting it all off again

-it's a life's work sorting out all these tiny jobs and getting the car exactly right again!

[Heuer]

Mark

Anything that will witness will do - talc, chalk, red grease, black grease, soot, carbon, ketchup - you just need something that will be displaced on contact. Be creative!

[Heuer]

Steve

Lotus Elan SE spinners are indeed the opposite to Jaguar - male rather than female. This was probably an attempt by Colin Chapman to avoid paying royalties to Jaguar/Dunlop who bought the rights to the Rudge Whitworth system. No surprises there of course but the patent stood firm as it was all about the cones and Chapman had to pay up.

Lotus spinner on right:



The Elan hubs were not splined but rather used peg drive. Despite all this (opposite thread, male cones, peg drive) the wheels still failed for a different reason - they cracked between the peg holes and the vents:


Elan (and Black & Decker workmate) designer Ron Hickman admitted he failed to spot the error and the problem would not have existed if he had arranged for the peg holes to be drilled between the vents.

[steve3.8]

Jaguar must have had quite an income at the time from spinners then , with MG ,Healey ,Aston,Triumph etc..

What surprised me was that Lotus threads are in the opposite direction as we all know what happens if we fit Jaguar hubs on the wrong side of the car !.

Mark , ebay is your friend for the marking blue [in a tube] , but as David says almost anything can be used . If you are hands on with maintenance and repairs it is helpful for confirming fitting of components .

[Heuer]

Yes but the hub threads are also the opposite direction so it works as advertised. Chapman wanting to prove everyone wrong again or maybe he thought doing it that way would "add lightness" by making the spinner smaller. Certainly the aluminium spinner used on the Elan 26R was incredibly light:

Standard Elan eared spinner: 0.600 kg / 1.3 lb
Elan 26R spinner: 0.23 kg / 0.5 lbs
E-Type spinner: 885gms / 3 lbs

[Series1 Stu]

E-Type spinner: 885gms / 3 lbs

885g=approx. 2lb where I come from.

Regards

[Heuer]

Well I was wrong on both counts. The repro E-Type spinner weighs 2lb 6oz, whatever that is in euros.