411/412/603 wheel nut torque?

[browning l]

Originally Posted by Kevin Howard

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?

[RGSchmitt]

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

[Hydroglen]

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

[Rubbond]

Wow - for once someone agrees with me!

[Kevin H]

Originally Posted by Hydroglen

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!

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?

Originally Posted by RGSchmitt

I recall there are standard values for torquing bolts, based on bolt grade, size, etc. Such as
BOLTS AND TORQUE SPECS

And there is a well known book among racers only on fasteners, by Carroll Smith.

Anything similar for other graded, non-US fasteners?

Bob

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!

[Kenneth Andrén]

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

[David Olivant]

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

[Claude]

Originally Posted by Hydroglen

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!
Dorien

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.

[Kevin H]

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.