Square taper, grease or not!!!!

retrobate":3px4crs5 said:

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.

Click to expand...

Presumably their CNC machine was lubricated with finest extra virgin viper oil? :twisted:

Of course tightening the same amount will require less torque with lube.

It does not automatically follow that tightening to the same rating as recommended for a dry fit will cause deformation.

I have never used a torque wrench to tighten cranks on my own bikes, though I have to add my experience mostly pre-dates the newer materials.

Perhaps the Raleigh Grifter was named with a healthy dose of tongue in cheek afterall...

No More Nails... works like a charm :twisted:

I used to grease, then I read (on the interweb :shock: ) that it might allow the crank to slide further up the tapers & cause damage, so now I don't grease, and I've never had any issues with either method in over 20years of MTB.
Hell, in ye olden days I used to whack the cranks onto the greased axle with a lump hammer and a block of wood before tightening the bolts down, and those cranks never worked loose

I don't grease, for boring engineering reasons.

Haven't we all realized that it really doesn't matter yet? I've been installing bottom brackets both privately and professionally for the last 24 years and haven't had an issue with either technique.

C'mon - let's see if we can get this thread to 10 pages of going round in circles.

gerryattrick":iw661uhe said:

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.

Click to expand...

It's only my opinion. Perhaps it's idiot but since I've got titanium parts, I grease quite everything with cupper grease.

24pouces":17ninm09 said:

gerryattrick":17ninm09 said:

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.

Click to expand...

It's only my opinion. Perhaps it's idiot but since I've got titanium parts, I grease quite everything with cupper grease.

Click to expand...

Sound reasoning, because if you don't they may never come apart...

,,,had to cut a lightweight 'quick release' skewer off my Explosif because the alloy nut had 'cold-welded' to the titanium thread! :facepalm:

I used to think I didn't grease, then realised I'd been wiping the spindles with a greasy rag before fitting the cranks, so actually I'd been greasing all along. Whatever you put in there won't still be there by the time the crank's tight anyway, it all gets squooged out (you can see metal-to-metal contact on the spindle when you take the crank off).

I don't believe* it's possible to damage the tapers of a crank by overtightening, assuming a normal human and a spanner of conventional length. If they go on too far, they were already broken. The thing that knackers crank tapers is undertightening or just fatigue.

*this is exactly that, a belief, no sums involved, merely some experimentation