Square taper, grease or not!!!!
- Thread starter dicoverybmw
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We_are_Stevo
Old School Grand Master
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legrandefromage":2cm1cvjm said:
Just as well, because I already 'dibbed' it on your behalf...
...proxy-dibbing
Gents,
These tests are an excercise in "relative" reference. They prove nothing, nor were they intended to. They do demonstrate a couple of interesting things though. The amount of suckon on the BB spindle, both drive and non-drive side) is has a high, positive coorelation to what was used on the crank bolt threads. The inverse does not appear to be true hois not true.
Dry taper test series - in general
Dry taper greased threads most suckon distance
Dry taper dry threads next
Dry taper, AS (LocTite) threads least suckon distance (and IMHO, with chainline implications).
The greatest suckon distance came with greased taper, non-DS, greased threads using Park Polylube (3.577mm). The absolute least suckon distance came with AS'ed taper (LocTite) and AS'ed threads.
Oh, used acetone for AS removal, followed by isopropyl alcohol. Having to redo the later set of tests. Got a bit cold ouside in the garage last night, brought the stuff inside to finish, and the temperature increase really affected the tests - invalidated them. Alluminum crank alloy has a significant coeffiecient of expansion. Warm crank on a cold spindle wrecked the test series and I had to wait until stuff all got warmed up to room temp.
More to come...
Again, these test prove nothing, other than perhaps that I'm a blithering idiot getting sucked into this.. Do I hear the sqeal of dry tapirs yet?
These tests are an excercise in "relative" reference. They prove nothing, nor were they intended to. They do demonstrate a couple of interesting things though. The amount of suckon on the BB spindle, both drive and non-drive side) is has a high, positive coorelation to what was used on the crank bolt threads. The inverse does not appear to be true hois not true.
Dry taper test series - in general
Dry taper greased threads most suckon distance
Dry taper dry threads next
Dry taper, AS (LocTite) threads least suckon distance (and IMHO, with chainline implications).
The greatest suckon distance came with greased taper, non-DS, greased threads using Park Polylube (3.577mm). The absolute least suckon distance came with AS'ed taper (LocTite) and AS'ed threads.
Oh, used acetone for AS removal, followed by isopropyl alcohol. Having to redo the later set of tests. Got a bit cold ouside in the garage last night, brought the stuff inside to finish, and the temperature increase really affected the tests - invalidated them. Alluminum crank alloy has a significant coeffiecient of expansion. Warm crank on a cold spindle wrecked the test series and I had to wait until stuff all got warmed up to room temp.
More to come...
Again, these test prove nothing, other than perhaps that I'm a blithering idiot getting sucked into this.. Do I hear the sqeal of dry tapirs yet?
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You mean sucked on to this I assume...
If ever history was being made, it's right here! As said, sterling effort and looking forward to the results!
Some comments to expand on FC:
c) which leaves the better crank taper and bottom bracket surface.
> this is an important one. More so to the crank of course. Would be good if you could note "ease of removal" although this really is not the issue or a motive to lube in the first place IMHO. I've removed horrid cranks from
cheap and nasty city bikes that have stood outside in extreme weather - eventually any corrosion does brake
but it initially requires a lot more force. Don't ask if I could remove the pedals though...
e) what will each be like in a year in a dry shed... a salt winter commute and muddy rides.
> could you also do a good 200 miles hard riding up some mountains in +35C, then in -10c, and
note if any cranks fall off or work loose and make a nice plot of pre-load loss in the crank bolt.
Keep us posted - this thread will be epic!
Some comments to expand on FC:
c) which leaves the better crank taper and bottom bracket surface.
> this is an important one. More so to the crank of course. Would be good if you could note "ease of removal" although this really is not the issue or a motive to lube in the first place IMHO. I've removed horrid cranks from
cheap and nasty city bikes that have stood outside in extreme weather - eventually any corrosion does brake
but it initially requires a lot more force. Don't ask if I could remove the pedals though...
e) what will each be like in a year in a dry shed... a salt winter commute and muddy rides.
> could you also do a good 200 miles hard riding up some mountains in +35C, then in -10c, and
note if any cranks fall off or work loose and make a nice plot of pre-load loss in the crank bolt.
Keep us posted - this thread will be epic!
dicoverybmw
Retrobike Rider
Hmmmmmm didn't expect this thread to run to quite this length, anyway fitted the cranks today, no grease on tapers, threadlock on bolts and a little grease under the head of the bolts, thanks again for all the replies and only one more thing to add, I'm still as sat on the fence as when we started!!!
Cheers Darren.
Cheers Darren.
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I assemble my cranks and tapers with sea-water.
Ok in an attempt to reach the 10 page point.
gdb2b - Love your work but in addition to my many years working in aircraft maintenance I have spent the last 10 years doing R & D for an aerospace company that sounds a bit like playbus.
I have to tell you that Im not going to accept your results without a minimum of three similar results from repeated testing of each configuration all conducted in a controlled environment and supported by calibration certificates for your torque wrench and measuring equipment.
:facepalm: I cant belive that I have stooped so low just to get to 10 pages
Next please
gdb2b - Love your work
but in addition to my many years working in aircraft maintenance I have spent the last 10 years doing R & D for an aerospace company that sounds a bit like playbus. I have to tell you that Im not going to accept your results without a minimum of three similar results from repeated testing of each configuration all conducted in a controlled environment and supported by calibration certificates for your torque wrench and measuring equipment.
:facepalm: I cant belive that I have stooped so low just to get to 10 pages
Next please
