411/412/603 wheel nut torque?
 

Does anyone know an official recommended figure for the 411 wheel nut torque with the Avon Safety wheels fitted? (I assume the same would apply to the 412 and 603)

This leads to another question - if a 3rd party car mechanic is working on your car, is it your responsibility to tell him/her what the wheel nut torque should be?

Or put another way, can a mechanic deny or reject responsibility for a road wheel falling off because I as the owner of the car have not told them what the torque should be?

So long as the legal system (ours, perhaps yours) allows anyone capable of paying the fees to file a lawsuit. you'll get as many answers as there are suits. Logic plays no part in it unless you have precedents already established.

Common sense would dictate prudence on the part of both the mechanic and the owner.

411/412/603 wheel nut torque?
 

"Common sense would dictate prudence on the part of both the
mechanic and the owner."

In other words, if you would rather not be driving with a wheel
falling off, know the right torque values and watch the wheel being
reinstalled accordingly!

411/412/603 wheel nut torque?
 

In my experience, wheels usually fall off because the garage mechanic simply
forgot to tighten the nuts at all.
In small garages usually the result of going off to answer the 'phone.
If do your best with a standard wheel wrench (with the wheel back on the
ground of course) this will normally be more than adequate.
I wouldn't advise the mechanic about anything. Let him pretend the wheel is
a brand new component, and he should be able to get his head around that.
I lost 4 out of 5 wheel nuts on the front left-hand wheel of a Range Rover
(on the motorway!) about 3 years ago. It starts with a vibration as if
you've lost a balancing weight, but when you slow down, it's not nice at
all. The Anti-theft nut seems to stay on longest.
On that occasion the garage actually admitted they had forgotten to tighten
the nuts after replacing the brake pads. (It happened within 40 km).
How could you sue someone that honest? He even supplied the new nuts at his
cost! Don't use him any longer of course.
I also once got a cup of boiling water spilled over my stomach at an airport
in the USA (they call it coffee there). I guess that was the first million I
lost?
More recently I lost 2 nuts on a Discovery, over1000 miles after the last
service. I think that time it was the front right wheel.
It is logical isn't it, that the left wheel nuts will always loosen more
quickly, due to friction and gyroscopic forces?
Maybe Top Gear could put this to the test on their track.
Wheel nuts on Land Rovers by the way are very expensive. I believe they are
stainless steel, so they don't rust solid as with many cars.
I wonder if people just steal them?

411/412/603 wheel nut torque?
 

Alfa Romeo and many Chryslers + had reversed threads so that left is left
and right is right so basically self tightening.
I always tighten my own wheels and in the rare occasions when a shop does
it, I have them use a hand wrench.
Anybody who allows a garage to use an impact gun on wheel nuts is inviting
disaster. The impact damages the nuts and may overtighten them as in an
effort to be safe, the settings are set too high....then try undoing them
when you have a flat.
Dorien

411/412/603 wheel nut torque?
 

You would need to show that the mechanic was negligent to succeed in
a claim. Trying to show he did not torque the nuts properly would be
nearly impossible and very expensive to prove especially if he had a
good laywer.

If you specify the torque and it's wrong it definately ends up back
in your lap.

This isn't about to become the subject of a law suit, but the topic came up (again) yesterday because I finally picked my 411 up from the mechanic who has had it for the last 9+ years.

The mechanic and I have had quite a lot of correspondence lately in which I have criticised numerous events in relation to my car, which in a roundabout way I was saying were down to either his negligence or at the very least a poor decision on his part. Yesterday he went about denying responsibility for every one of these events for one reason or another, in most cases claiming we had conversations that we did not in fact have. One of these issues was the wheel falling off when I went to road test the car earlier this year.

He said he asked me for the torque settings, which he didn't, and went on to say that in the absence of any manufacturers information regarding wheel nut torque I supposedly told him to use the same settings as a Jensen, which apparently is 55 ft/lbs. This is in fact a complete fabrication of the truth because we never had any such conversation.

Okay, so what should the torque value be for the wheel nuts?

And in real life how many owners of Bristols, or any other car, (a) know what the torque spec is, and (b) supervise the mechanic doing up the wheel nuts with a torque wrench?

411/412/603 wheel nut torque?
 

Hi,

I discussed this with Norman at Motor Wheel Services and he suggested 80ft/lbs for my Arnolt.

Best

Kenenth

411/412/603 wheel nut torque?
 

Wow, I am so glad you have got the car back, it has been a long saga
demanding immense patience on your part.
I think I might in my younger days have given him a Rugby kiss on the nose.
Have you now to finish the car?
You could do a TV programme on Rogue Traders.
Kind regards,
nick

Thanks Nick. It is nice to have it back and I'm not known for my patience! Unfortunately it still needs work even in the engine bay. My new engine leaks oil! Apparently because the sump pan is buckled. Given the amount of money I have spent on it and the fact that he bought new intake manifold, pistons, cam shaft, valves, distributor (x2), carby/throttle body (x2) and God knows what else from the USA, you would think he would have bought a new sump pan, but no. There are other issues as well, but I digress!

As no one seems to know what torque the V8 wheels nuts should be tightened to, whoever is next speaking to Brian Marelli next can you please ask him.

Maybe that should be whomever ...

No, "whoever" is correct, as it the subject of the phrase, not the object.

Why don't you call him, or email the plant at lilianbristolcars@tiscli.co.uk,to the attention of Jeff Marsh?

411/412/603 wheel nut torque?
 

I recall there are standard values for torquing bolts, based on bolt
grade, size, etc. Such as
http://www.raskcycle.com/techtip/webdoc14.html And there is a well
known book among racers only on fasteners, by Carroll Smith.

Anything similar for other graded, non-US fasteners?

Bob

411/412/603 wheel nut torque?
 

I am constantly surprised by this odd question. A wheel should be
tightened by hand, using the hand tools provided and removed the same way.
Assuming average strenght this equates to some 70 / 80 lbs but it is quite
irrelevant.
You are not going to bother with a torque wrench or even have one when
dealing with a flat on the highway!!
Wheels have been tightened by hand around the world for some 80 years, and I
have certainly never come across this issue except on this Forum!
I am also very much involved in racing and many of my fellow racers have to
re and re their wheels by hand. Take it as a fact that the stress and
loading on the track far exceed the requirements or stresses of a Bristol!
I am leaving in a few hours for a car tour of Continental Europe. Based on
past experience, I know that after a suitable breakfast I will be able to do
or undo the wheel nuts on my car and my wheels will not over-take me on the
Stelvio!
Dorien

411/412/603 wheel nut torque?
 

Wow - for once someone agrees with me!

And it seems wheels have also been falling off cars for years!

It's only ever happened to me once, but once is enough to get you thinking about it. However, as I said at the beginning of the thread, the topic has come up as the subject of a dispute in which I am being told it's my fault because I didn't supply the official (Bristol factory) torque specifications for the wheel nuts!

While this cannot possibly be used as an excuse by the mechanic involved, I do however think it is a valid question, because there will be a minimum torque figure. It may be Dorien, that you always comfortably exceed that figure when you tighten your wheel nuts, but does everyone? Or are all the stories of wheels falling off are down to the nuts not being under any torque at all?

Bob, I have Carrol Smith's book (thanks for reminding me) and it quickly becomes clear that there are so many variables that it would be impossible to list all the recommended torque values.

As an example, there is a table in the book titled "Recommended tightening torque for AN-3 through AN-20 and AN-73 through AN-81 bolts."

Below the table is says "All values are for clean and dry cadmium plated nuts and bolts without a lubricant. Use of a thread lubricant will make these values invalid".

The point being, that not only do recommended values change when using a lubricant, but they change for every different type of lubricant!

Thanks Kenneth. I have seen figures of 70-100 ft/lb quoted from Geoff Dowdle, but this is quite a large range. Mine are apparently now 95 ft/lb. Of course I only have the mechanics word on this, which is beginning to prove quite unreliable, so I will check them!

411/412/603 wheel nut torque?
 

Hi,

I have lost wheels twice over the last 60 years, apart from my pedal car and "three wheel bicycle", and both times I lost the nuts holding the bolt-on hub extensions for the wire wheels. Both LH rear wheels...any pattern apart from uneven wire wheels? I was doing 70-80 kph

Kenneth

411/412/603 wheel nut torque?
 

The 'hand tight' explains why different sizes of spanner are different
lenghts, to compensate for average human force applied.
In many cases wheel nuts coming loose can be attributed to other factors,
namely dirty threads, burrs on the nating surfaces[of nut and wheel and
wheel and axle.
Take the time to clean and inspect all mating surfaces, apply a LITTLE
grease to the stud and tighten with the supplied spanner. I would further
recommend that the nuts be rechecked after a few, say ten, miles.
It works for me.
regards,
David

Bristol a bit aero
 

Bristol cars were originally designed and assembled by aeroplane builders, and this tradition of a higher standard has remained, even if there were periods when the cars in fact saw the standards slip; sometimes to below general automotive standards.

When I took training for my pilots license the preflight inspection was a non-negotiable. The pilot paid attention to any potential hazard that could cause the plane to touch earth in an inconvenient way and made sure they knew what to do to prevent risk. Only twice in my flying career did it prove of value. Once, I found the magneto bracket snapped, and the other, far more serious, found an inattentive pilot had struck my prop with his wing and bent it, whilst on the tiedown. That one cost $2,000 and grounding for two weeks, but it may have cost a bit more if the bent part had snapped in the air (presuming I would not have noticed on warm-up).

That tradition tends to suffuse this forum, so that its members are constantly seeking information that better prepare them to keep their cars safe, especially when in motion. Yes, you can pull a Bristol 411 over to the side of the road when the wheel starts to wobble, whereas the winged Bristol Beaufighter has fewer options, but the mess of a wheel fall-off at 100 mph is still unnerving at best.

The value in this discussion will come from members adding wheel check to their post mechanic-touched-it inspection, if not their daily preflight. I never cease to be amazed when I preflight my wife's car to find tyres at 15 pounds, for example, and in the Alfa, the engine oil down below the minimum mark on the stick.

Claude

PS: Picking up on the other forum discussion on Fighter's knobs, it seems Mr. Silverton is honouring the aeroplane heritage in detail design in the cars. This is good, in my view, as it has a sense of authenticity rather than branding. I have always enjoyed the no-nonsense design aspect of aero, milspec functionality. I like the idea that a gauge is held in by screws I can see, rather than requiring special tools or disassembly of half the dash in order to get to change the bulb on an instrument. It is an ethos of the company, and of its aficionados on this forum.

Official Avon wheel nut torque figure
 

The official recommended wheel nut torque figure from Bristol is 90 ft lbf. This is for a 411 wearing Avon Safety wheels, although I'm sure it's the same for the 412 and 603 with the same wheels.