Ideal Torque for hub bolts

Hi,
I have bought a torque wrench so I have been trying to decide on the
best torque for my hub bolts.

The assembly in question is "Unicycle.com Wide CrMO Hub":
http://tinyurl.com/wdh0

The bolts supplied with it are M8 x 1mm pitch marked 12.9

from searching the Internet it seems a figure of between 29 & 36 foot
pounds is appropriate.

Has anyone got any more info or expertise in this area please?

The reference I have used a
http://dodgeram.org/tech/specs/bolts/M_bolts.html
http://tinyurl.com/ythok
http://www.bsn.com/Cycling/Torques.html
http://tinyurl.com/3eygf


The following may also be of interest to any hardcore bolt
investigators:
http://tinyurl.com/2b464
http://www.onlineconversion.com/torque.htm

I hope I haven't over done the references :-~

Thanks,
/\/\


--
mike.hinson - Unicyclist since Nov 2000

"I have to overcome a 'stress hill' when tightening the nuts, but once
installed they sit in a 'stress valley'. "

--Klaas Bil
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40-50 is ideal
my suzue threads wrecked at 90


--
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40-50 is ideal
my suzue threads wrecked at 90


--
Sofa - you - pee - dee

'A circus clown is just a carny who's too stupid to flip a ride switch
on and off. Now, you take a circus clown, roll him on the barn floor,
kick him in the head a couple hundred times, and what have you got?' -
Hank Hill


'Unicycle Product Reviews' (http://tinyurl.com/368h6) *107* reviews on
*72* products

'London Unicycling Club Website ' (http://www.brianmackenzie.com/LUC/)
version 3.02


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On Tue, 15 Jun 2004 13:43:33 -0500, "Sofa" wrote:

40-50 is ideal
my suzue threads wrecked at 90

That's in lb.ft isn't it? I've seen 40 lb.ft recommended elsewhere.
That (ideal) translates to about 56 - 70 Nm if I didn't mess up the
conversion.

But I've been meaning to ask: is this related to hub strength? Could a
Suzue, being a reasonably strong hub, handle more nut torque than your
run-of-the-mill pisbakkenstaal hub before stripping?

Klaas Bil - Newsgroup Addict
--
I was right when I made the mistake. - doofe

On Tue, 15 Jun 2004 13:43:33 -0500, "Sofa" wrote:

40-50 is ideal
my suzue threads wrecked at 90

That's in lb.ft isn't it? I've seen 40 lb.ft recommended elsewhere.
That (ideal) translates to about 56 - 70 Nm if I didn't mess up the
conversion.

But I've been meaning to ask: is this related to hub strength? Could a
Suzue, being a reasonably strong hub, handle more nut torque than your
run-of-the-mill pisbakkenstaal hub before stripping?

Klaas Bil - Newsgroup Addict
--
I was right when I made the mistake. - doofe

Klaas Bil wrote:
*On Tue, 15 Jun 2004 13:43:33 -0500, "Sofa" wrote:

40-50 is ideal
my suzue threads wrecked at 90

That's in lb.ft isn't it? I've seen 40 lb.ft recommended elsewhere.
That (ideal) translates to about 56 - 70 Nm if I didn't mess up the
conversion.

But I've been meaning to ask: is this related to hub strength? Could
a
Suzue, being a reasonably strong hub, handle more nut torque than
your
run-of-the-mill pisbakkenstaal hub before stripping?*


I think you are right Klaas, I may have a chance to do some tests if I
can find a nut sponsor, and also redo Sofa's tests but using lubricant
too.

I also think the bolt torque is likely to be less because it is smaller,
anyone got any suggestions on the bolt torque please?

Thanks,
/\/\


--
mike.hinson - Unicyclist since Nov 2000

"I have to overcome a 'stress hill' when tightening the nuts, but once
installed they sit in a 'stress valley'. "

--Klaas Bil
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Klaas Bil wrote:
*On Tue, 15 Jun 2004 13:43:33 -0500, "Sofa" wrote:

40-50 is ideal
my suzue threads wrecked at 90

That's in lb.ft isn't it? I've seen 40 lb.ft recommended elsewhere.
That (ideal) translates to about 56 - 70 Nm if I didn't mess up the
conversion.

But I've been meaning to ask: is this related to hub strength? Could
a
Suzue, being a reasonably strong hub, handle more nut torque than
your
run-of-the-mill pisbakkenstaal hub before stripping?*


I think you are right Klaas, I may have a chance to do some tests if I
can find a nut sponsor, and also redo Sofa's tests but using lubricant
too.

I also think the bolt torque is likely to be less because it is smaller,
anyone got any suggestions on the bolt torque please?

Thanks,
/\/\


--
mike.hinson - Unicyclist since Nov 2000

"I have to overcome a 'stress hill' when tightening the nuts, but once
installed they sit in a 'stress valley'. "

--Klaas Bil
------------------------------------------------------------------------
mike.hinson's Profile: http://www.unicyclist.com/profile/1652
View this thread: http://www.unicyclist.com/thread/33216

While we're on the subject, do foot-pounds convert directly to
inch-pounds by multiplying by 12? My torque wrench reads inch-pounds,
so I've been torqing to 480 inch-pounds. Just wanted to make sure.
Thanks.

Andy


--
quark soup - Frood who knows where his towel is.

quark soup

"OK, so ten out of ten for style, but minus several million for good
thinking, yeah? " - Douglas Adams
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"quark soup" om writes:

While we're on the subject, do foot-pounds convert directly to
inch-pounds by multiplying by 12? My torque wrench reads inch-pounds,
so I've been torqing to 480 inch-pounds. Just wanted to make sure.
Thanks.

Yes. Torque is force (pounds, newtons, etc.) multiplied by the length
of the lever arm. One pound of force acting at a distance of one foot
is 1 ft-lb or 12 in-lb.

Ken

Klaas Bil wrote:
*But I've been meaning to ask: is this related to hub strength? *

No. Just about any hub spindle will take bolt torques far greater than
the recommended level.

The torque limit is to protect the crank hole from stretching too much.
The bolt torque is directly related to the amount of pressure the bolt
exerts on the crank, which is in turn directly related to the outward
pressure that the tapers exert on the inside of the crank hole. Both
the threads and the tapers are shallow wedges that multiply the force
you exert with the torque wrench.

If the torque level is too low the crank isn't firmly pressed on to the
tapers and it will "squirm" under load and loosen. If the torque level
is too high then it will micro-rupture the crank.

Fortunately the pitch of the threads and the angle of the spindle tapers
are fairly standard, so the torque levels for various cranks tend to be
a function of the quality of the crank. It's a rough guide, but without
the actual manufacturer's recommended torque it's better than nothing.


40 foot-lbs is about right for a good set of bicycle cranks. Sugino
used to make a low-end set that could take only 25 ft-lbs, and I believe
one of the Shimano Dura-Ace sets could take 50 ft-lbs. These are all
fairly high quality, forged aluminum cranks. I have no idea what a cast
aluminum or steel crank would require.


--
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I was standing in the park wondering why frisbees get bigger as they get
closer. Then it hit me.
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