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PostPosted: Tue Feb 26, 2013 9:52 am 
Old School Grand Master
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Joined: Sun Sep 05, 2010 1:10 am
Posts: 4756
Location: Heathfield, East Sussex
...if you were a female member of the forum that would take on a whole different meaning!

But no, I left it out to save weight for the Shipping...:lol:


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PostPosted: Tue Feb 26, 2013 10:21 am 
Old School Grand Master
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Joined: Sun Sep 05, 2010 1:10 am
Posts: 4756
Location: Heathfield, East Sussex
hollister wrote:
We_are_Stevo wrote:
but it happened at too opportune a moment not to include it here... :|

:

That tells me all I need to know


The piano player just stopped playing, tumbleweed rolls down the street outside, and an attractive woman with a low neckline screams off camera... :twisted:


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PostPosted: Tue Feb 26, 2013 12:39 pm 
.o.T.M Triple Crown Winner
.o.T.M Triple Crown Winner
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Joined: Sun Dec 31, 2006 12:59 pm
Posts: 3135
Location: Sunny South of France
We_are_Stevo wrote:
...if you were a female member of the forum that would take on a whole different meaning!


With or without… grease on the tool ? :mrgreen:


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PostPosted: Tue Feb 26, 2013 1:26 pm 
retrobike rider
retrobike rider
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Joined: Thu Jan 21, 2010 11:13 am
Posts: 1311
Location: I don't know, the satnav's bust!
WOW! Six pages of views and no significant majority on either side. That must show it doesn't matter either way so stick with whatever method you prefer, it won't make a bit of difference apparently.


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PostPosted: Tue Feb 26, 2013 1:31 pm 
Gold Trader / MacRetro rider
Gold Trader / MacRetro rider
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Joined: Sun May 25, 2008 11:03 am
Posts: 18212
Location: Sunny Glasgow
Experiment
Take to bikes and leave them down the coast for a couple of months.Say 4 as cranks arent taken off regularly + tbf its a hell of a lot longer than that sometimes years or decades.
Bike A gets greased taper
Bike B gets no grease on the taper.
Torque both cranks the same[probably best to use the same model if possible]

Camp .Greasy taper- state the ungreased crank may seize on
Camp .Dry as a bone - state the ungreased crank will come off easily

Talk is cheap,the only real way to resolve this is to maybe try the above :?


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PostPosted: Tue Feb 26, 2013 2:37 pm 
Retro Guru

Joined: Tue Feb 06, 2007 5:50 pm
Posts: 946
Location: Over there -->
dyna-ti wrote:
Experiment
Take to bikes and leave them down the coast for a couple of months.Say 4 as cranks arent taken off regularly + tbf its a hell of a lot longer than that sometimes years or decades.
Bike A gets greased taper
Bike B gets no grease on the taper.
Torque both cranks the same[probably best to use the same model if possible]

Camp .Greasy taper- state the ungreased crank may seize on
Camp .Dry as a bone - state the ungreased crank will come off easily

Talk is cheap,the only real way to resolve this is to maybe try the above :?

The problem with this proposal is the "Torque both cranks the same[probably best to use the same model if possible]" bit. for the same torque applied to the threads, the greased taper will have moved further (the grease reduces the friction between the surfaces, requiring a lower torque on the tightening tool to move the same distance along the taper). So, if we torque the cranks up to the ideal torque for the ungreased setup, the greased setup will have moved further along the taper, causing plastic deformation to the softer part of the system (almost certainly the aluminium crank rather than the steel bottom bracket axle), thus permanently damaging the cranks.

I am on the "dry as a bone" side of this argument and have never yet had a crank arm seize onto a square taper bottom bracket, not in the 30+ years that I've been faffing about with bikes.


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PostPosted: Tue Feb 26, 2013 2:40 pm 
King of the Skip Monkeys
King of the Skip Monkeys
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Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26168
Location: Moomin Valley
Some grease goes 'off' after few years and goes powdery (lithium grease?) causing more problems than curing.


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PostPosted: Tue Feb 26, 2013 8:28 pm 
Old School Grand Master
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Joined: Sun Sep 05, 2010 1:10 am
Posts: 4756
Location: Heathfield, East Sussex
grahame wrote:
The problem with this proposal is the "Torque both cranks the same[probably best to use the same model if possible]" bit. for the same torque applied to the threads, the greased taper will have moved further (the grease reduces the friction between the surfaces, requiring a lower torque on the tightening tool to move the same distance along the taper). So, if we torque the cranks up to the ideal torque for the ungreased setup, the greased setup will have moved further along the taper, causing plastic deformation to the softer part of the system (almost certainly the aluminium crank rather than the steel bottom bracket axle), thus permanently damaging the cranks.


Not according to the Bods at Raceface... :wink:


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PostPosted: Tue Feb 26, 2013 9:20 pm 
Retro Guru

Joined: Sat Dec 03, 2005 11:16 pm
Posts: 300
Location: Bristol uk
From the Raceface data.

Cranks tend to "suckon" to a greased spindle approximately 0.5mm
(0.020") further than they would onto a dry spindle
using the same torque value (28 ft/lbs. max.) on the
crank bolt. We have taken this into cons ideration in
the CNC machining of our tapers to ensure it is not a
problem.


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PostPosted: Tue Feb 26, 2013 9:42 pm 
BoTM Winner / PoTM Winner
BoTM Winner / PoTM Winner
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Joined: Sat Jan 13, 2007 10:44 pm
Posts: 1184
Location: norcal
Lol!


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