Square taper, grease or not!!!!

Woz":1cctyacu said:

That's because it's a BB Installation Instruction and not a Crank Installation Instruction.

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Point taken

Still, your comment sent my into my kitchen cabinets, where I keep the NOS parts (what else do you use a kitchen for?).
Neither the Altus A-10 nor the Xt M730 crankset manual mention grease, but then again those are both from the early 90s.

EDIT : And we've reached page 15 !!!! :facepalm:

Raging_Bulls":25u3dgfg said:

I still had an unopened UN-55 box, so I opened it, took out the instructions and scanned the complete English page. Here it is :

POINT A- As you may notice, it doesn't mention grease on the tapers. The BB comes with grease inside the axle bolt treads and the manual only mentions greasing the threads that connect it to the frame. but NOT on the tapers.


And sorry, but I can't let this one slide :

dyna-ti":25u3dgfg said:

So far were had reports from engineers[real ones not wannabees) .BMW was mentioned as was raf [rocketys etc] and British aerospace[my dad] add to this Sheldon brown himself

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POINT B. BMW and the RAF have their field of expertise. However it doesn't include BBs.
I'll take the word from someone who has done plenty of miles on bikes he maintains himself over that of any engineer who doesn't work for a bicycle component manufacturer.
My own experience (20 years of maintaining my own bikes, around 120K miles total) indicates that it doesn't matter one iota whether you grease them or not. POINT C- Creaking is usually the result of sand/dirt on the tapers, not from lack of grease.

POINT D- As for Sheldon Brown mentioning using grease, does he by any chance tell you to use a specific grease that you can coincidentally buy via his website?
After reading the chain cleaning article/commercial, I've learned to take his words with a grain of salt ... or rather a mountain of it. IMO he doesn't mind telling absolute nonsense if that enables him to sell a few more things.

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DEAR LORDY You've lost it
Point A- I take it you missed the bit about it being installed by a qualified mechanic.
Point B- These are engineering institutions ,they've not been designing ,building and repairing on an amateur level all this time and 20yrs faffing about with your own stuff doesnt really compare as any sort of experience when it comes down to it.
Point C- Dry faces Not dirt be that a speck or a grain or whatever.

I'll take the word from someone who has done plenty of miles on bikes he maintains himself

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On Sheldon Brown":25u3dgfg said:

I've learned to take his words with a grain of salt

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Eh? :? Im not following this logic here

dyna-ti":3ikp7xqm said:

Point A- I take it you missed the bit about it being installed by a qualified mechanic.
Point B- These are engineering institutions ,they've not been designing ,building and repairing on an amateur level all this time and 20yrs faffing about with your own stuff doesnt really compare as any sort of experience when it comes down to it.
Point C- Dry faces Not dirt be that a speck or a grain or whatever.

I'll take the word from someone who has done plenty of miles on bikes he maintains himself

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On Sheldon Brown":3ikp7xqm said:

I've learned to take his words with a grain of salt

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Eh? :? Im not following this logic here

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Point A : Seeing as it comes with fitting instructions, the manual is obviously made for whoever installed the BB. They mention grease where it's installed in the frame and put grease in the bolt threads, but not on the tapers.
I know it's not a crank fitting manual, but the BB is half of the combination. If they take care of the bolt threads, I'd really expect the tapers to be taken care of too if that were necessary.

Point B : Shimano and SRAM are engineering institutions too, and unlike the others they actually specialize in bike parts.

Point C : Feel free to clarify that, or at least make a structured sentence out of it. I can't do that, it's just a collection of words to me and I can't seem to figure out their meaning. Perhaps it's the language barrier, I don't know.

As for not following my logic in the Sheldon Brown thing, I do know that chain thing was a joke and think he knew what he was doing in most areas, but I am pretty sure he was wrong on this one.
As I said, from my experience it makes no difference. I've replaced plenty of BBs and fitted plenty of square taper cranks, and never had a reason to put grease on there.
Maybe sarcasm just doesn't work in writing after all.

Tell me more, tell me more....

Charlieboy28":jpg3smn6 said:

Contrary to popular belief, the crank/bb assembly of a bike is NOT a
friction-fit, nor is it really a press-fit... it is an INTERFERENCE-fit. What's
holding the cranks on is the plastic deformation of the metals involved.

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A crank taper is NOT an interference fit, it is a clearance class fit. The crank is held fast by a bolt, not by friction between surfaces. The taper flats are for transmitting drive torque from the crank, not to hold the crank onto the taper!

RadNomad":3dnch6al said:

Charlieboy28":3dnch6al said:

Contrary to popular belief, the crank/bb assembly of a bike is NOT a
friction-fit, nor is it really a press-fit... it is an INTERFERENCE-fit. What's
holding the cranks on is the plastic deformation of the metals involved.

Click to expand...

A crank taper is NOT an interference fit, it is a clearance class fit. The crank is held fast by a bolt, not by friction between surfaces. The taper flats are for transmitting drive torque from the crank, not to hold the crank onto the taper!

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YES IT IS


Clearance fit
It is a fit that always enables a clearance between the hole and shaft in the coupling. The lower limit size of the hole is greater or at least equal to the upper limit size of the shaft. WRONG
Transition fit
It is a fit where (depending on the actual sizes of the hole and shaft) both clearance and interference may occur in the coupling. Tolerance zones of the hole and shaft partly or completely interfere. WRONG
Interference fit
It is a fit always ensuring some interference between the hole and shaft in the coupling. The upper limit size of the hole is smaller or at least equal to the lower limit size of the shaft. RIGHT


AND IF YOU WERE RIGHT YOU WOULDNT NEED CRANK PULLERS , oops soz caps, or grease for that matter

i thought the square taper was to index the cranks relative to each other

Raging_Bulls":1sb46kio said:

dyna-ti":1sb46kio said:

Point A- I take it you missed the bit about it being installed by a qualified mechanic.
Point B- These are engineering institutions ,they've not been designing ,building and repairing on an amateur level all this time and 20yrs faffing about with your own stuff doesnt really compare as any sort of experience when it comes down to it.
Point C- Dry faces Not dirt be that a speck or a grain or whatever.

I'll take the word from someone who has done plenty of miles on bikes he maintains himself

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On Sheldon Brown":1sb46kio said:

I've learned to take his words with a grain of salt

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Eh? :? Im not following this logic here

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Point A : Seeing as it comes with fitting instructions, the manual is obviously made for whoever installed the BB. They mention grease where it's installed in the frame and put grease in the bolt threads, but not on the tapers.

dyna":1sb46kio said:

again, the fitting instructions are for a qualified mechanic. I got a big pile of paperwork with my gas boiler including fitting and repairing instructions and an exploded diagram .According to your logic its expected ill do the installation for it.

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I know it's not a crank fitting manual, but the BB is half of the combination. If they take care of the bolt threads, I'd really expect the tapers to be taken care of too if that were necessary.


Point B : Shimano and SRAM are engineering institutions too, and unlike the others they actually specialize in bike parts.

dyna":1sb46kio said:

Hmm :? bike parts :? Now what is the name of the field that deals with bike parts :? Hmm let me think :? Oh Yes ENGINEERING

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Point C : Feel free to clarify that, or at least make a structured sentence out of it. I can't do that, it's just a collection of words to me and I can't seem to figure out their meaning. Perhaps it's the language barrier, I don't know.

dyna":1sb46kio said:

Or perhaps its sarcasm as the parting shot of a failed argument

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dyna":1sb46kio said:

I say failed but what i mean is is incomplete as 'failed' implies you had a chance in the first place

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As for not following my logic in the Sheldon Brown thing, I do know that chain thing was a joke and think he knew what he was doing in most areas, but I am pretty sure he was wrong on this one.
As I said, from my experience it makes no difference. I've replaced plenty of BBs and fitted plenty of square taper cranks, and never had a reason to put grease on there.
Maybe sarcasm just doesn't work in writing after all.

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dyna":1sb46kio said:

Oh, i dunno, you seem to have the sarcasm down to a T Im confident youve been replacing BB's and cranks and all other thinks bikey and are mostly competent in doing so,im not denying that.Im just saying that without a background where you at least have an understanding of the important principles involved it could well be youve been doing it incorrectly for 20yrs

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Here is something i know for sure
An email from Shimano's chief design engineer plus one from Sram's and if it were possible one from Fred Dibnah himself would fail to change your way of thinking.
Here is something else i know-

Raging Bull":1sb46kio said:

"I'd really expect"

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The flaw to your argument.

PS
Dry faces is the term to describe to meeting faces that havent first been prepared with a lubricant. Sure ,there are loads of instances where a lube isnt required but that doesnt apply to metal parts exposed to the elements.

mikee":1sb46kio said:

i thought the square taper was to index the cranks relative to each other

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Bad Mikee, BAD
Reminds me of a funny story
Picture the scene if you will, of a Saturday afternoon in early summer. The setting is a local bike shoppe filled with bike mechanics and assorted cyclists and other hanger ons drinking coffee and talking bikey stuff(could be confused with heaven except for the wages)
~The bell on the door goes and a customer enters pushing their pride and joy.
Being busy with the important duties of talking bikes and drinking coffee we pick the lowest common denominator ,namely the owners 17yrold son to take care of the customer.
From the front he announces(like we were listening) that the crank has loosened off and needs bolted back on.
being surrounded by bikes and mechanics all his life our young 'director' gets on with the job of refitting the crank. As he has been so very well trained he does of course grease the taper and refit the crank and bolted it on.I assume he used a torque wrench but as i didnt see i couldnt say for sure.I'd imagine though
Customer leaves and we get back to the important stuff.
5 mins later the customer returns saying they have a problem.
Our young mechanic had fitted both cranks on the same way. Easy to happen given his age and experience. His incompetence paled into all insignificance though when we discovered that the customer hadnt noticed for over 100 yrds
100 YARDS :shock: :shock: Did they think it normal for both knees to move in unison.

Charlieboy28":2s2c8ebi said:

Interference fit
It is a fit always ensuring some interference between the hole and shaft in the coupling. The upper limit size of the hole is smaller or at least equal to the lower limit size of the shaft. RIGHT

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WRONG! :facepalm:

This refers to parallel surfaces where the hole is actually smaller than what you are fitting into it, NOT a taper fit...

...a good example of an 'interference fit' is a steel bearing in an alloy crankcase where you heat the crankcase, freeze the bearing and fit the one t'other; or a steel liner in an alloy cyclinder, NOT something that requires A BOLT to hold it in place...

...Jeez!

More fuel for the fire.

Just been digging in the cave and have found the fitting instructions for Middleburn RS2 and Syncros Revolutions, both recomend a dry interface.