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PostPosted: Sun Apr 28, 2013 8:46 pm 
PoTM Winner
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1) do you grease the tapers?

2) do you grease the thread of the crank bolt, or leave it dry or use thread lock?

3) what torque (Nm) do you use for the crank bolt?


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PostPosted: Sun Apr 28, 2013 9:09 pm 
Old School Grand Master
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I always installed the cranks dry, a smidge of grease on the bolts and did it up tight. Rode it for a bit and re-tightened, not sure what torque, just tight :D

Shaun


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PostPosted: Sun Apr 28, 2013 9:17 pm 
PoTM Winner
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This is what I have read so far ... Seems to warn against re-tightening after the correct installation.

http://sheldonbrown.com/brandt/installing-cranks.html


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PostPosted: Sun Apr 28, 2013 9:43 pm 
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.......just being OCD I suppose. Like checking the nuts holding the car wheels on are tight after a few miles of use.

The force going on the taper will simply displace the lubricant as the alloy undergoes elastic deformation to fit the taper on the axle. Microwelds will form but hopefully won't go anywhere. As opposed to the microwelds that form in the head set causing "brinelling" in the straight ahead position.

Shaun


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PostPosted: Mon Apr 29, 2013 1:22 am 
rBoTM Winner
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There was a long thread on here a few weeks back and the general consensus was that the tapers should be greased. A few actual engineers (i say this tongue in cheek) weighed in and said that the theory that you did not need grease was bogus. And if you have ever disassembled an old bike chances are you are grateful for every micro-spec of grease some old mechanic used. Just passing the word along. Thread here:


viewtopic.php?f=1&t=244624&start=0


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PostPosted: Mon Apr 29, 2013 1:25 am 
rBoTM Winner
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After reading it again there was more disagreement than consensus....


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PostPosted: Mon Apr 29, 2013 9:26 am 
PoTM Winner
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Crikey .... I only made it to page 6.

I think I will go with grease and a dry bolt with a dot of thread lock at the top of the shaft torqued to 40nm.

Some good arguments on that thread ...


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PostPosted: Tue Apr 30, 2013 6:51 pm 
PoTM Winner
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Just reinstalled my cranks. Went dry in the end.

First time I'd installed a tapered crank for years.

Didn't feel nice, I guess as you wind the bolt in the tapers are mating.

Just trusted the torque wrench.


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PostPosted: Tue Apr 30, 2013 6:59 pm 
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The tape ranks a controversial topic - I don't grease them but plenty do.

No point greasing threads as the massive pressures causes the grease to flow away from the thread-thread contact points, so it nil use as an anti-seize but will fill the voids and prevent moisture ingress. May as well use a proper anti seize appropriate to the metals beig used.

Depends on the make, whether they're new or used bolts etc.


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PostPosted: Tue Apr 30, 2013 9:17 pm 
rider | rBoTM Winner
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I just wipe my greasy fingers (only a very light film) on the axle tapers before I fit the crank. I think general consensus always used to say don't grease because you can then overtighten the crank onto the axle and wear/distort the tapers in the aluminium.


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