Square taper installation question

[johnniecakes]

When installing a square taper crankset is it proper to lubricate the spindle/crank arm interface or leave it dry? If it gets lubed grease or anti-seize. Any idea of the torque for tightening the arm onto the spindle?

Thanks !!!

[oldpotatoe]

When installing a square taper crankset is it proper to lubricate the spindle/crank arm interface or leave it dry? If it gets lubed grease or anti-seize. Any idea of the torque for tightening the arm onto the spindle?

Thanks !!!

In the 30 or so years of wrenching, including being service manager 3 times and owner but main wrench, once, I have always torqued to spec on dry spindles.

30 ft pounds is a good place. For interference fit, with a tapered spindle and crank interface, to be able to predict where the crank will end up with that torque-dry.

Hooboy, let the games begin!!

BTW-I have never needed to 'retorque', recheck', or anything else. On my own cranks and the cranks of a scad of customers over those 30 years. Particularly when the ONLY cranks were square taper. Use a torque wrench, feel is just that, 'feel' and varies. You can gorilla a square taper to break crank bolts, or bottom out crank/spindle easily, particularly if you make the mistake of greasing the taper.

[ultraman6970]

Put teflon tape in the cups threads and a lot of grease in the BB shell threads, so any of the cups specially the fixed one doesnt get frozen. I would not use loctite, never needed it even with the far superior italian threading. This will help with the possible creaks too.

As for the axle and arm joint, just put some grease too, more than nothing to avoid the undesirable creaks.

As for torque, honestly cant tell you because I do everything by feel, even if you put all your weight in the tool the crank and the bolt wont go any further, so just crank it up, you don't want the bolts to get lose, put some grease in the bolts threads also.

Hope this helps.

ps: do you see? two different opinions, potato has the torque wrench i do not :p

[DfCas]

This may be the most argued topic ever discussed on the internets. I do grease the tapers to help make removal easier. Some don't.

[shovelhd]

Grease the cups, spindles clean and dry. Remove any grease, dirt, and grime from the spindle and crank surfaces before installation. I like those surfaces to be squeaky clean. I've seen too many 80's Record and SR crankarms ruined.

[Gummee]

This may be the most argued topic ever discussed on the internets. I do grease the tapers to help make removal easier. Some don't.

Yup. Another religious argument.

I've done it both ways, but I remember reading (somewhere) that its supposed to be dry.

M

[oldpotatoe]

Yup. Another religious argument.

I've done it both ways, but I remember reading (somewhere) that its supposed to be dry.

M

"Most manufacturers (Specialites TA and White Industries being notable exceptions) recommend that square-taper cranks be fitted to the bottom bracket "dry", with no grease or other lubricant. See for example Campagnolo Crankset manual http://www.campagnolo.com/repository/documenti/en/7225254_Crankset-07-05.pdf where on page 28 it says "degrease axle and crankset square heads thoroughly."

Wikipedia goes on to say this is one of the mosthotly debated topics.

I do dry, do whatever blows yer skirt up.

[Lewis Moon]

Dry. I too have seen ruined Record cranks.

[FlashUNC]

Dry all the way. Lube everything else -- retaining bolt threads, cup threads, bearings (obviously).

[paredown]

I'm a believer in dry 'n torqued---but clean threads on the bolts, and in the case of Campy, I do replace the blue Loctite on the threads once clean.

[veloduffer]

Dry...I thought this topic, which was frequent back in the day, had gone the way of the Dodo bird. :p

[ergott]

Dry. It's been explained in above posts well enough that I have nothing better to add. Just reinforcing that as the accepted method as per the people that make them.

[Ralph]

On the two Campy square taper cranksets I use, and following Campagnolo Instructions in the manuals that came with the cranks, I install with dry spindles into dry cranks, install with a TQ wrench, and lube the heck out of everything else. Also I lube the crank arm bolts. But be careful doing that so as to not over tighten. 30 lbs tq on a greased bolt not the same as 30 lbs tq on dry bolt.

[zap]

Since I use Phil Wood bb I alway's followed Phil's recommendation, a dab of oil.

https://www.philwood.com/philpdfs/crankbearinginstallationguide.pdf

Also check the faq section on the website.

[Pastashop]

Here comes that dead horse again...

The torque wrench cannot guarantee sufficient engagement if subject to variable friction between the crank and the spindle, which occurs when it's "dry". One gets lucky that the native aluminum oxide on the crank mount faces is fragile enough that it starts to spall off, but that cannot always be consistent.

So, grease to ensure consistent amount of elastic strain for a given torque every time.

What one should avoid is re-tightening the bolt after it "becomes loose", as consequence of the crank squirming its way onto the spindle (minor amount of plastic deformation as consequence of pedaling). Retightening the bolt will eventually split the crank.

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

[oldpotatoe]

Here comes that dead horse again...

The torque wrench cannot guarantee sufficient engagement if subject to variable friction between the crank and the spindle, which occurs when it's "dry". One gets lucky that the native aluminum oxide on the crank mount faces is fragile enough that it starts to spall off, but that cannot always be consistent.

So, grease to ensure consistent amount of elastic strain for a given torque every time.

What one should avoid is re-tightening the bolt after it "becomes loose", as consequence of the crank squirming its way onto the spindle (minor amount of plastic deformation as consequence of pedaling). Retightening the bolt will eventually split the crank.

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

Really? Which grease? What viscosity? How about STP?

[merckx]

I've done dry since 1973 and my cranks have never had kittens.

[Pastashop]

The goal is to get to a particular value of strain in the crank mount location to guarantee a set amount of pre-load. (The stress-strain curve is monotonic in the elastic regime.) Because the grease is an incompressible fluid and there is ample escape path, you will get to a point where the grease is all squeezed out from the interface, save for what's trapped in the microscopic cracks and pits. That trapped grease effectively planarizes the surface at a microscopic level and reduces the stiction during the installation process. My understanding is that these microscopic imperfections are precisely the reason one wants the grease there at the start – to facilitate the sliding. Even water would probably work, if it could be guaranteed to stay and plagiarize the surface.

But, like I said earlier, the native aluminum oxide is sufficiently weak that it works well enough in many cases, but probably cannot guarantee that the "torque spec" results in the same amount of preload every time.

Also: http://xkcd.com/386/

:-)

[oldpotatoe]

The goal is to get to a particular value of strain in the crank mount location to guarantee a set amount of pre-load. (The stress-strain curve is monotonic in the elastic regime.) Because the grease is an incompressible fluid and there is ample escape path, you will get to a point where the grease is all squeezed out from the interface, save for what's trapped in the microscopic cracks and pits. That trapped grease effectively planarizes the surface at a microscopic level and reduces the stiction during the installation process. My understanding is that these microscopic imperfections are precisely the reason one wants the grease there at the start – to facilitate the sliding. Even water would probably work, if it could be guaranteed to stay and plagiarize the surface.

But, like I said earlier, the native aluminum oxide is sufficiently weak that it works well enough in many cases, but probably cannot guarantee that the "torque spec" results in the same amount of preload every time.

Also: http://xkcd.com/386/

:-)

Light reading in the AM...monotonic? Is that only one type of tonic in your gin and tonic???
plagiarize????yikes. Shouldn't copy others works dude

Ugg, me bike wrench, do what Campagnolo says, ugggg.

[fuzzalow]

Here comes that dead horse again...

The torque wrench cannot guarantee sufficient engagement if subject to variable friction between the crank and the spindle, which occurs when it's "dry". One gets lucky that the native aluminum oxide on the crank mount faces is fragile enough that it starts to spall off, but that cannot always be consistent.

So, grease to ensure consistent amount of elastic strain for a given torque every time.

What one should avoid is re-tightening the bolt after it "becomes loose", as consequence of the crank squirming its way onto the spindle (minor amount of plastic deformation as consequence of pedaling). Retightening the bolt will eventually split the crank.

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

Install square tapers dry.

I hear mumbo jumbo like the above and I am glad I do my own wrenching. The contact patch between crankarm and spindle is a contact press fit with a large distribution of force across 4 large flats. The crankarm gets pressed on and it's held on by a spindle bolt/washer.

The crankarm does not function like a bolt where the elastic deformation of the threaded bolt shaft is integral to the function as to how a bolt retains its ability to remain fastened. The theory learned behind fasteners is not applicable here for a crankarm.

[oldpotatoe]

Install square tapers dry.

I hear mumbo jumbo like the above and I am glad I do my own wrenching. The contact patch between crankarm and spindle is a contact press fit with a large distribution of force across 4 large flats. The crankarm gets pressed on and it's held on by a spindle bolt/washer.

The crankarm does not function like a bolt where the elastic deformation of the threaded bolt shaft is integral to the function as to how a bolt retains its ability to remain fastened. The theory learned behind fasteners is not applicable here for a crankarm.

Hooorayyy

[Pastashop]

Sorry about the tech speak. A "monotonic stress-strain curve" just means that there is a one to one relationship between stress and strain. That is, for a given amount of applied force, you get one and only one amount of deformation (aka preload). It's how materials work in the elastic(spring-back perfectly) regime. For the interface in question, the deformation upon preloading is basically imperceptible to the naked eye, but it is there.

[Pastashop]

The fact that a crank arm does not function like a bolt does not mean that it doesn't need preload to work properly. Consider press-fit bottom brackets. In an earlier thread, everyone was complaining about those due to creaking, etc. Without a proper press fit, it will move about (hence the noise). A better press fit would involve heating the shell to expand it, popping in the insert, and letting it cool to compress around the insert; the result: preload and adequate retention without threads.

[Pastashop]

https://janheine.wordpress.com/2012/04/16/to-grease-or-not-to-grease/

[Dude]

Most manufacturers will specify in the directions whether it will be dry or with lube. Campy specified dry for their tapered bb spindles - as did Shimano.

Anecdotally, if nothing is specified for tapered, I would always do dry, never had any loosening. I was also a mechanic for ~10 years - so take that FWIW.

Any crank where there is a physical interface (splined, etc) I grease it - never had any issues.

[Gummee]

Like I said above: religious argument

Y'all carry on. I'm at work and bored.

M

[zap]

we need a popcorn munching smiley.

:banana::banana::banana::banana::banana::)

[Gummee]

we need a popcorn munching smiley.

:banana::banana::banana::banana::banana::)

:lurk over at ADVRider

M

[Fivethumbs]

Della Santa told me on more than one occasion don't' grease 'em. Good enough for him, good enough for me.


Sent from my iPhone using Tapatalk

[El Chaba]

Whenever he would see a jacked up car my dad would always remark that the automobile makers spent millions of dollars on engineering and yet some teenage kid thought he knew better as to how to somehow "improve" the car....I follow the manufacturer's recommendation....The Campy cranks go on the square taper dry and the TA's go on with a little smear of grease. Both seem happy.

[Pastashop]

One word: Pinto

[tylerbick]

Although the OP prolly had no idea, so no offense implied, but, what I heard in my head when I read the thread title was "here we go again". I love all the engineer speak. Back at it gentlemen...

[oldpotatoe]

https://janheine.wordpress.com/2012/04/16/to-grease-or-not-to-grease/

But that depends on the air pressure of the tires on the bike.

[FlashUNC]

https://janheine.wordpress.com/2012/04/16/to-grease-or-not-to-grease/

Jan's article very much reads like "Do whatever the manufacturer tells you to do."

OP hasn't specified, but if its a Campy crank, they're explicit in the directions: No grease.

[mcteague]

Have always done my own work and had square taper cranks for many a year. Always used dry installation, never had any problems with the fit.

Tim

[Mark McM]

Like I said above: religious argument

Y'all carry on. I'm at work and bored.

M

The debate about whether the sun revolves around the earth or whether the earth revolves around the sun was widely considered to be a religious argument during Gallileo's time. But now that the facts and mechanisms are known, it is established fact that the earth revolves around the sun.

As Pastashop and others have related, the mechanism by which lubricating the tapers assures a more consistent press fit is also now known, so the advantage of lubricating tapers is also no longer a religious argument.

The Catholic church eventually accepted Gallileo's ideas to be correct. Hopefully it won't take the Paceline Forum as long to come around.

[FlashUNC]

The debate about whether the sun revolves around the earth or whether the earth revolves around the sun was widely considered to be a religious argument during Gallileo's time. But now that the facts and mechanisms are known, it is established fact that the earth revolves around the sun.

As Pastashop and others have related, the mechanism by which lubricating the tapers assures a more consistent press fit is also now known, so the advantage of lubricating tapers is also no longer a religious argument.

The Catholic church eventually accepted Gallileo's ideas to be correct. Hopefully it won't take the Paceline Forum as long to come around.

This is some pretty fantastic false equivalency. Couldn't just go for the two-fer and throw in a quick nod to Godwin's Law while at it?

[oldpotatoe]

One word: Pinto

Gelding

[Mark McM]

This is some pretty fantastic false equivalency. Couldn't just go for the two-fer and throw in a quick nod to Godwin's Law while at it?

Not really. The arguments for dry tapers generally boils down to either "That's what the authorities have told me", or "I've always done it that way"; in other words, it is taken as an article of faith, rather than reason.

Instead, the lubricated taper argument relies on facts, logic, engineering analogy, and experimental evidence; in other words, reason rather than faith.

Installing taper cranks can often achieve a press-fit that is "good enough" - but sometimes not. Lubricating the tapers provides a more consistent press-fit, so it will the achieve the desired press-fit more often than dry tapers.

[Mark McM]

Really? Which grease? What viscosity? How about STP?

So, your argument is that the static friction between dry surfaces is more consistent than the friction between lubricated surfaces?

[FlashUNC]

Not really. The arguments for dry tapers generally boils down to either "That's what the authorities have told me", or "I've always done it that way"; in other words, it is taken as an article of faith, rather than reason.

Instead, the lubricated taper argument relies on facts, logic, engineering analogy, and experimental evidence; in other words, reason rather than faith.

Installing taper cranks can often achieve a press-fit that is "good enough" - but sometimes not. Lubricating the tapers provides a more consistent press-fit, so it will the achieve the desired press-fit more often than dry tapers.

So you're assuming that the manufacturers who recommend that you don't grease the tapers -- the people who developed the product -- know less about the product than outsiders?

I don't know why anyone would use parts from someone who, quite frankly, they thought were idiots.

[deanster]

No grease on the spindle (oldpotatoe is right). Make sure the taper is the same for the cranks and spindle. All the instructions from Campy state "No Grease." In addition the books i have on the subject from Jim Langley (bicycling), Lenard Zinn, and John Barnett all state "Dry no grease." Infact Zinn in "Zinn and the Art of Road Bike Maintenance" talks about the reason why one doesn't use grease on P133 "Using grease can cause the soft Aluminum to slide too far onto the harder metal steel spindle when torquing and distort the Al (me:which would cause stress fractures and damage the Al)." There is NO "Reason" behind any use of grease just bad wrenching. I have had Campy, Phi Wood, Stronglight, Shimano, Sugino, and T/A BB/Crank arm combinations and all the instructions (and my practice) have Never used grease...infact I always cleaned the spindle and crank receiver with alcohol and a clean rag to make sure the grease was gone and the surfaces were clean and dry. Using the recommended torque has always been a good practice and there has never been a problem removing cranks with the correct extraction tool. Torque wrenches are relatively cheap when comparing the replacement cost of bike parts.
Use Grease at your own risk but IT IS A VERY BAD IDEA!

[Pastashop]

"Sliding too far" is an indication either of poor design / manufacturing, or a FUD tactic. A taper made to spec with known materials will produce a predetermined amount of preload, provided there are no egregious errors in manufacturing or uncontrolled variables, such as inconsistent friction or non-spec torque during installation. "No grease" keeps the preload lower than with grease, but the extent of it is relatively inconsistent. Those are physically provable facts. And the crank is this heavier than it truly needs to be, owing to the lack of control the manufacturer has in how installations are actually done. (Lots of bike mechanics avoid using a torque wrench; do we start arguing that issue, too?)

But people's experiences aren't negated -- they are instances.

Did you know that 40% of car buyers will buy a different make of car if their favorite color is unavailable?.. How rational is that? But the thing they are maximizing depends a lot on color, I guess. Do I do that?.. Sure! It's all good if it works for you. I'll grease 'em, you degrease 'em!

[Mark McM]

So you're assuming that the manufacturers who recommend that you don't grease the tapers -- the people who developed the product -- know less about the product than outsiders?.

I make no such assumptions. The question of consistency of press-fit is directly testable, so a conclusion on the efficacy of lubricating the tapers can be made from the available evidence. Most of the arguments against lubricating tapers can be found to be incorrect through direct observation, if one only cared to look. To claim that dry tapers must be better just because an authority says it is risks committing the logical fallacy of Argument from authority (http://en.wikipedia.org/wiki/Argument_from_authority).

It is very possible that the manufacturers haven't actually tested the dry/lubricated taper issue. Because dry tapers work most of the time, they may simply working from dogma. The design of this joint has been standardized for so long, its likely that all prior assumptions are no longer questioned.

[Mark McM]

No grease on the spindle (oldpotatoe is right). Make sure the taper is the same for the cranks and spindle. All the instructions from Campy state "No Grease." In addition the books i have on the subject from Jim Langley (bicycling), Lenard Zinn, and John Barnett all state "Dry no grease." Infact Zinn in "Zinn and the Art of Road Bike Maintenance" talks about the reason why one doesn't use grease on P133 "Using grease can cause the soft Aluminum to slide too far onto the harder metal steel spindle when torquing and distort the Al (me:which would cause stress fractures and damage the Al)."

This is a case of poor analysis leading to a wrong conclusion. Here's why:

The bolt is not carry the crank load in the crank/spindle joint - it is the press-fit (elastic pre-load) between crank and spindle that carries the load. The purpose of he bolt is to drive the crank onto the spindle to create the press fit. Since lubrication decreases the friction between crank and spindle, a smaller bolt torque is required to drive the crank onto the spindle the necessary distance to create the elastic pre-load.

The error Zinn and many other have made is using the same bolt torque with both dry and lubricated tapers, thus potentially exceeding a safe press-fit pre-load with the lubricated spindles.

[fuzzalow]

OK, I'll bat this one around a little. All for the sake of harmless fun. I am not a mechanical engineer but I know full well the importance of precision in words and in practice, to say nothing of the danger in relying on junk theory.

Y'know, a good lie has to have a kernel of truth in it to be convincing and believable. And so does any misrepresentation or misunderstanding of science, or it cousin discipline - engineering, make for conjuring up junk facts to make something that is false sound believable and true.

The Campagnolo square taper crank & spindle is a compound mechanical device. It is based on two simple mechanical things that date back to the time of the ancient Egyptians: the wedge and the screw.

Not really. The arguments for dry tapers generally boils down to either "That's what the authorities have told me", or "I've always done it that way"; in other words, it is taken as an article of faith, rather than reason.

Instead, the lubricated taper argument relies on facts, logic, engineering analogy, and experimental evidence; in other words, reason rather than faith.

Installing taper cranks can often achieve a press-fit that is "good enough" - but sometimes not. Lubricating the tapers provides a more consistent press-fit, so it will the achieve the desired press-fit more often than dry tapers.

Respectfully and all in fun, the reasoning given here is outta left field, there is no meaningful way to define what is meant by a "more consistent press fit". A precision press fit is reliant on a corresponding match of the taper and dimensions of each of the mating surfaces. Thats it. Grease or not has nuthin' to do with it.

Where the 2-bit mechanics got it crossed up is where there was the practice to lubricate bolt threads in order to get an accurate torque reading because friction from the threads might cause under-torque of the bolt. This happens and the bolt is not elastically deformed enough to retain the clamping force required of the fastener or to ensure structural integrity of the bolt.

The square taper of a Campy crank does not rely on the taper, or the wedge part if you will, to remain affixed to the spindle. Greasing the taper won't make it "more consistent press-fit" better because that precision fit has already been guaranteed by the lovely manufacturing capabilities in Vincenza. If greasing tapers somehow makes it 'mo bedda than how Campy made and designed it to be, well then have at it and be my guest.

The bolt/washer on the end of the spindle, the screw part if you will, provides all the clamping power necessary to maintain the integrity of the crank on the spindle. Apply grease to the bolt threads here if you like and maybe it will improve the accuracy of the torque wrench reading.

Man, don't you just hate it when somebody throws reason in your face as a reason and that reason turns out to be no reason at all.

All above said in ribbing and in fun.

[rustychisel]

OK, I'll bat this one around a little. ...
The Campagnolo square taper crank & spindle is a compound mechanical device. ...

Where the 2-bit mechanics got it crossed up is where there was the practice to lubricate bolt threads in order to get an accurate torque reading because friction from the threads might cause under-torque of the bolt. ...

Greasing the taper won't make it "more consistent press-fit" better because that precision fit has already been guaranteed by the lovely manufacturing capabilities in Vincenza.


Well argued and persuasively, IMHO.

Yet, having greased tapers on cranks since 1978 and never having one fail, or deform, or badly loosen, I think perhaps the argument might just as well be "How do I accurately judge the torque needed to do the job?"

That seems to be the nub of it.

[Mark McM]

Where to begin, where to begin ...

Respectfully and all in fun, the reasoning given here is outta left field, there is no meaningful way to define what is meant by a "more consistent press fit". A precision press fit is reliant on a corresponding match of the taper and dimensions of each of the mating surfaces. Thats it. Grease or not has nuthin' to do with it.

Respectfully, I don't think you understand how an interference (press-fit) joint works. It relies on more than just the precision of the tapers. In order to ensure full load distribution across the entire contact surfaces under all modes of loading, and to prevent movement between the surfaces, the surfaces must be pre-loaded (pressed together). This is done by pushing the crank up the taper, creating an pre-load on the surfaces as the crank hole is elastically expanded the taper elastically compressed.

Clearly, there is some optimum amount of pre-load required for this joint - not enough, and there may be movement in the joint and the loads may not be distributed evenly across the surfaces, shortening the life of the joint. Too much, and your risk permanently deforming/damaging the components.


Where the 2-bit mechanics got it crossed up is where there was the practice to lubricate bolt threads in order to get an accurate torque reading because friction from the threads might cause under-torque of the bolt. This happens and the bolt is not elastically deformed enough to retain the clamping force required of the fastener or to ensure structural integrity of the bolt.

The bolt torque is selected to deliver the force necessary to drive the crank up the taper to the desired pre-load (interference fit). Bolt torque has to take into account the bolt thread pitch (thread angle), friction on the threads, and friction between taper surfaces. However, dry friction between surfaces is much less consistent than lubricated surfaces, so lubrication of the surfaces can reduce the variability of the torque required to drive the crank the correct distance up the taper. An additional benefit is that the reduced friction with lubrication can reduce the torque required.

The square taper of a Campy crank does not rely on the taper, or the wedge part if you will, to remain affixed to the spindle. Greasing the taper won't make it "more consistent press-fit" better because that precision fit has already been guaranteed by the lovely manufacturing capabilities in Vincenza.

Not quite true - regardless of how well the Vicenza manufactured the parts, there is no press-fit at all until the bolt torque drives the crank up the spindle taper. And greasing the taper allows the taper to be driven a more consistent distance/pre-load for a given bolt torque.

The bolt/washer on the end of the spindle, the screw part if you will, provides all the clamping power necessary to maintain the integrity of the crank on the spindle. Apply grease to the bolt threads here if you like and maybe it will improve the accuracy of the torque wrench reading..

If the clamping force of the bolt were enough to hold the crank on, we could use a much steeper taper on the spindle, and not have to use a special tool to pull the crank off for disassembly. The reason for the shallow taper is because the pre-load across the taper surfaces needs to be much higher than the bolt clamping force (essentially, the bolt is driving a high leverage wedge).

So, the primary purpose of the bolt force is drive the crank up the taper (wedge), and keeping the crank from working back down the taper is its secondary purpose. And as noted earlier, greasing all the surfaces produces a more consistent distance the crank is "wedged" up the spindle for a given bolt torque.

[oldpotatoe]

Where to begin, where to begin ...



Respectfully, I don't think you understand how an interference (press-fit) joint works. It relies on more than just the precision of the tapers. In order to ensure full load distribution across the entire contact surfaces under all modes of loading, and to prevent movement between the surfaces, the surfaces must be pre-loaded (pressed together). This is done by pushing the crank up the taper, creating an pre-load on the surfaces as the crank hole is elastically expanded the taper elastically compressed.

Clearly, there is some optimum amount of pre-load required for this joint - not enough, and there may be movement in the joint and the loads may not be distributed evenly across the surfaces, shortening the life of the joint. Too much, and your risk permanently deforming/damaging the components.




The bolt torque is selected to deliver the force necessary to drive the crank up the taper to the desired pre-load (interference fit). Bolt torque has to take into account the bolt thread pitch (thread angle), friction on the threads, and friction between taper surfaces. However, dry friction between surfaces is much less consistent than lubricated surfaces, so lubrication of the surfaces can reduce the variability of the torque required to drive the crank the correct distance up the taper. An additional benefit is that the reduced friction with lubrication can reduce the torque required.



Not quite true - regardless of how well the Vicenza manufactured the parts, there is no press-fit at all until the bolt torque drives the crank up the spindle taper. And greasing the taper allows the taper to be driven a more consistent distance/pre-load for a given bolt torque.



If the clamping force of the bolt were enough to hold the crank on, we could use a much steeper taper on the spindle, and not have to use a special tool to pull the crank off for disassembly. The reason for the shallow taper is because the pre-load across the taper surfaces needs to be much higher than the bolt clamping force (essentially, the bolt is driving a high leverage wedge).

So, the primary purpose of the bolt force is drive the crank up the taper (wedge), and keeping the crank from working back down the taper is its secondary purpose. And as noted earlier, greasing all the surfaces produces a more consistent distance the crank is "wedged" up the spindle for a given bolt torque.

Many, many thanks, excellent.... I'll continue with dry, but thanks.

[unterhausen]

I love these never-ending arguments. Sorta like which way to hang the toilet paper roll.

The reason I grease square tapers is to keep them from creaking. Any other argument pro and against and I cover my ears and go "la la la" at high volume.

The reason campagnolo said not to grease is because their grease had lithium in it and would promote corrosion in the interface. That's a really good way to ruin a crank

[fuzzalow]

@ Mark McM:

HaHa! OK, OK I dunno why your replies all seem predicated as if I don't use a crankarm bolt on my square taper cranks.

Hmmmmm. But y'know, I'm not too sure myself and maybe when I build up the bike I just put the crank on the square peg and off I go. Naw, I probably whack it on with a rubber mallet to be sure it ain't gonna 'dun come loose.

Somebody remind me it's winter time...

[zmudshark]

I use Campagnolo. I use square taper. I follow Campagnolo's recommendations.

If I were to ask advice on building Campagnolo, I would trust @oldpotatoe before @Mark McM unless Mark cares to share his chops with the rest of the group.

[Black Dog]

This is a case of poor analysis leading to a wrong conclusion. Here's why:

The bolt is not carry the crank load in the crank/spindle joint - it is the press-fit (elastic pre-load) between crank and spindle that carries the load. The purpose of he bolt is to drive the crank onto the spindle to create the press fit. Since lubrication decreases the friction between crank and spindle, a smaller bolt torque is required to drive the crank onto the spindle the necessary distance to create the elastic pre-load.

The error Zinn and many other have made is using the same bolt torque with both dry and lubricated tapers, thus potentially exceeding a safe press-fit pre-load with the lubricated spindles.

This is true but the question that needs to be answered is greasing actually necessary? Does the amount of variable friction between the dry faces during loading ever exceed the value that would result in a situation where there is not enough preload on the interface from the stretching of the crank and the compression of the spindle? I fully agree that an arguments from authority or antiquity are not compelling, at all.

However, no one here knows if this has been tested. We can assume that it has by the manufacturers or we can not. I would suspect (assuming here; I will only likely make an ass out of myself) that dry is preferred because it can prevent a ham fisted installer from splitting the crank due to the ease of over torquing with greased faces. So, grease may be superior from a technical stand point, but dry may be better from a practical one since it reduces the chance of damage from over tightening and in the relatively low forces generated on a bike the range of preloads that one might expect from dry fitting still exceeds the necessary minimum and remains below the maximum.

Just my two cents (and that is in Canadian Currency which would make is about 1.5 cents USD).

This is great fun and since I was teaching logical fallacies and inductive and deductive arguments to a university biology class today; very topical.

[Peter B]

<snip>

Greasing the taper won't make it "more consistent press-fit" better because that precision fit has already been guaranteed by the lovely manufacturing capabilities in Vincenza. If greasing tapers somehow makes it 'mo bedda than how Campy made and designed it to be, well then have at it and be my guest.


All above said in ribbing and in fun.

Given that a chunk of the lovely manufacturing is now in Romania I'll be using a thin wipe of Phil's Tenacious.

All above said in ribbing and in fun.

[ergott]

I use Campagnolo. I use square taper. I follow Campagnolo's recommendations.

If I were to ask advice on building Campagnolo, I would trust @oldpotatoe before @Mark McM unless Mark cares to share his chops with the rest of the group.

Mark's a smart guy, no need to call him out. This discussion is as old as the interface and there has been solid engineering talk from both camps.

I will say similar to Black Dog that it's possible that the difference between grease or no grease is within the margin of error required to keep the crank where it belongs. With the amount of cranks out there installed with and without grease you would have enough statistical evidence that there was a failure issue one way or the other.

[lonoeightysix]

what about greasing spindles in order to:

-facilitate removal, especially with suspect crank arm puller threads (poor metallurgy, corrosion damage, under-engineered)

-alleviate noise from poor fit and movement

i'd be apt to use anti-seize on low end componentry. i'd also be leery of a dry install on titanium spindles.

btw, henkel has some sort of wet vs dry torque conversion for their products, as a function of percentage.

[fuzzalow]

Given that a chunk of the lovely manufacturing is now in Romania I'll be using a thin wipe of Phil's Tenacious.

All above said in ribbing and in fun.

Whoa, I haven't been keeping up on current events pal, but there hasn't been a Campy square taper made in how long now?

Ah, Vincenza, she was a lovely memory...

[Peter B]

Whoa, I haven't been keeping up on current events pal, but there hasn't been a Campy square taper made in how long now?

Ah, Vincenza, she was a lovely memory...

Record Pista.

http://www.campagnolo.com/US/en/disciplines/track

But in all fairness, that one's probably still made in Vincenza.

[zmudshark]

Mark's a smart guy, no need to call him out. This discussion is as old as the interface and there has been solid engineering talk from both camps.

I will say similar to Black Dog that it's possible that the difference between grease or no grease is within the margin of error required to keep the crank where it belongs. With the amount of cranks out there installed with and without grease you would have enough statistical evidence that there was a failure issue one way or the other.
No disrespect meant. I know who Peter is, and trust him. I also trust the manufacturer. I have no idea who Mark is, or as I said, what his chops are. He could be the head square taper spindle guy for whoever still makes square taper spindles. I thought his posts were condescending, in any case.

[aaronf]

To those arguing for grease on the spindles of manufactures who recommend against it:
What is your recommendation (calculation expected, not anecdotal guesswork) for reducing the specified cranks bolt torque to prevent exceeding the elastic limit of the aluminum crank i.e. over-tightening to the point of plastic deformation/cracks/failure?

[fuzzalow]

Record Pista.

http://www.campagnolo.com/US/en/disciplines/track

But in all fairness, that one's probably still made in Vincenza.

No worries. So your tribulations here as interlocutor in getting wrapped around the axle about made-in-Vincenza-or-not has no bearing on the wording of my post that you responded to. ;) Your response quoted here, to me, is a gentleman's way of conferring "never mind", thank you. :) This is just conversation and I'll endeavor to be equally gracious to you in our future discussions.

[Here I reach across the table, grasp the bottle of single malt and pour you, and then myself, another dram while inquiring "We gonna finish this?".]

No disrespect meant. I know who Peter is, and trust him. I also trust the manufacturer. I have no idea who Mark is, or as I said, what his chops are. He could be the head square taper spindle guy for whoever still makes square taper spindles. I thought his posts were condescending, in any case.

Well, that's just Mark McM being Mark McM. I can see where you're coming from and it is nice for ergott to smooth stuff over but Mark McM can defend himself. Some guys are tone deaf, some dunno how to argue a point without making it personal, I'd guess Mark McM means well. Dunno, don't care. He bon mots to my posts presaged by saying:
Respectfully, I don't think you understand how an interference (press-fit) joint works.
Hey I dunno, HaHa I thought I was pretty smart! :no: :eek: What can I tell ya? Don't worryboudit.

It's winter time, right?

[johnniecakes]

I apologize for asking this question and stirring such a hornet's nest. For the record the crank in question is a 7400 series and I will be installing it dry. Please now everybody take a deep breath and relax, spring time is on it's way

[merlincustom1]

Don't apologize. Great thread.

[Peter B]

<snip>

Greasing the taper won't make it "more consistent press-fit" better because that precision fit has already been guaranteed by the lovely manufacturing capabilities in Vincenza. If greasing tapers somehow makes it 'mo bedda than how Campy made and designed it to be, well then have at it and be my guest.


All above said in ribbing and in fun.

Given that a chunk of the lovely manufacturing is now in Romania I'll be using a thin wipe of Phil's Tenacious.

All above said in ribbing and in fun.

Whoa, I haven't been keeping up on current events pal, but there hasn't been a Campy square taper made in how long now?

Ah, Vincenza, she was a lovely memory...

Record Pista.

http://www.campagnolo.com/US/en/disciplines/track

But in all fairness, that one's probably still made in Vincenza.



<snip>

No worries. So your tribulations here as interlocutor in getting wrapped around the axle about made-in-Vincenza-or-not has no bearing on the wording of my post that you responded to. ;) Your response quoted here, to me, is a gentleman's way of conferring "never mind", thank you. :) This is just conversation and I'll endeavor to be equally gracious to you in our future discussions.

[Here I reach across the table, grasp the bottle of single malt and pour you, and then myself, another dram while inquiring "We gonna finish this?".]




In the spirit of ribbing and fun, and to be clear, now that we're drinking pals, I'm not wrapped around any axle about what's made where. Just here talking current events and poking a bit of fun at the 'guaranteed fit' assumption.

And thanks for the scotch. Next round's on me. :beer:

[professerr]

To those arguing for grease on the spindles of manufactures who recommend against it:
What is your recommendation (calculation expected, not anecdotal guesswork) for reducing the specified cranks bolt torque to prevent exceeding the elastic limit of the aluminum crank i.e. over-tightening to the point of plastic deformation/cracks/failure?

Yep, that is the question here isn't it? Although I accept the greasers' technical arguments over the edumacated stabs at them (see also Jobst Brandt on this here: http://www.sheldonbrown.com/brandt/installing-cranks.html), what torque should you used for greased mounting when all you have is the recommended (and presumably higher) torque spec for cranks made by manufacturers who specify de-greased mounting?

[fuzzalow]

In the spirit of ribbing and fun, and to be clear, now that we're drinking pals, I'm not wrapped around any axle about what's made where. Just here talking current events and poking a bit of fun at the 'guaranteed fit' assumption.

And thanks for the scotch. Next round's on me. :beer:

Roger that. There are quite a few decent folks that hang out here whom would make tossing down a scotch or a brew with a mere formality given the chance to do so.

Lemme elaborate on the "guaranteed fit" comment which also gets back OT: I always thought that Campagnolo for some of its manufacturing was genuinely high tech and world leading in its day. The precision of the Nouvo Record crank & square taper was notable for bike component manufacturing in the early/mid 1960's. Was there a smoother bottom bracket or hub set than Campagnolo's during that era? There was nothing slop-dash about Campy machined interfaces. Hence the remark about "guaranteed fit" - I meant it as a true statement and not as a salvo of argumentative hyperbole.

Manufacturing seemed so much cruder back in the day of the pre-digitized CNC world. And yet they still made great products that would qualify as world class even today. Campy also made the Valentino and Gran Turismo dérailleurs - which upholds the absolute truism that nobody's perfect.

[oldpotatoe]

what about greasing spindles in order to:

-facilitate removal, especially with suspect crank arm puller threads (poor metallurgy, corrosion damage, under-engineered)

-alleviate noise from poor fit and movement

i'd be apt to use anti-seize on low end componentry. i'd also be leery of a dry install on titanium spindles.

btw, henkel has some sort of wet vs dry torque conversion for their products, as a function of percentage.

-in 30 years, never had a crank that would not come off, if installed 'dry'.

-samo, this dry crank install 'creak' is something I have never seen(or heard).

-do whatever ya like, I have been doing it this way for 30 years w/o any issue or problem. I don't have the RH cup of far superior italian threaded BB cups come unscrewed either.

-titanium BB spindles are a answer to a not asked question but there really is no issue with galling or corrosion on ti spindle, aluminum crank installs->dry as well.

Back to the popcorn!!

[El Chaba]

To those arguing for grease on the spindles of manufactures who recommend against it:
What is your recommendation (calculation expected, not anecdotal guesswork) for reducing the specified cranks bolt torque to prevent exceeding the elastic limit of the aluminum crank i.e. over-tightening to the point of plastic deformation/cracks/failure?

This is the wild card....and you will not get a good answer to it as the proponents have no clue as to what a substitute torque value may be....Which is why I just trust in old faith and -like an idiot-follow the recommendations of the manufacturer in question....

[DfCas]

If you remove the crank bolts on a square taper crank and ride it will the crank arms come off?

[Peter B]

If you remove the crank bolts on a square taper crank and ride it will the crank arms come off?

Yes. Primary variables are applied force and time.

[Mark McM]

I use Campagnolo. I use square taper. I follow Campagnolo's recommendations.

If I were to ask advice on building Campagnolo, I would trust @oldpotatoe before @Mark McM unless Mark cares to share his chops with the rest of the group.

Actually, I'm not asking anyone to believe me. I'm asking that they look at the facts and evidence and reach their own conclusions.

For example, it has been implied in this thread that the square taper joint is not a press-fit. All you have to do is observe the amount of force it takes to pull a crank off a spindle after installation to decide that point.

Another easily observable piece of evidence is noting the loss pre-load on the mounting bolt after use. Many people observe that when they go to remove a crank after some amount of use, that the bolt is much looser than when they installed it. The bolt does not actually have to unscrew to lose pre-load (also observable, if you mark the bolt head position after installation). What happens is that the crank shifts on the spindle tapers, loosening some of the pre-load on the bolt. If you compare the amount of bolt pre-load loss with a dry installed spindle vs. a lubricated spindle, you will likely notice that the dry installed spindle losses more bolt pre-load (I have done this test, and have observed this evidence). This would indicate that the lubricated spindle achieved a better press-fit during installation.

Don't believe that the crank moves on the spindle in use? Take a look at the faces of the tapers on a spindle that has been used. You'll find that the contact surfaces show some symptoms of rubbing and wear. The longer the spindle has been used, the more extensive these wear marks tend to be.

[Mark McM]

I will say similar to Black Dog that it's possible that the difference between grease or no grease is within the margin of error required to keep the crank where it belongs. With the amount of cranks out there installed with and without grease you would have enough statistical evidence that there was a failure issue one way or the other.

Actually, I agree with this. Even with dry tapers it is usually possible to reach an adequate press fit. However, it will require more bolt torque than with a lubricated spindle, and since there is more variability in dry friction, there will be more variability in the degree of press fit achieved. So it is entirely possible that with dry spindles and the lowest recommended torque, you might not reach an adequate press fit (inadequate press fit can result in bolts loosening up, which in turn can result in crank hole damage).

[Mark McM]

To those arguing for grease on the spindles of manufactures who recommend against it:
What is your recommendation (calculation expected, not anecdotal guesswork) for reducing the specified cranks bolt torque to prevent exceeding the elastic limit of the aluminum crank i.e. over-tightening to the point of plastic deformation/cracks/failure?

Crank manufacturer usually recommend upper and lower limits of bolt torque. Generally, the lower end of the torque range will work with lubricated spindles.

As noted previously, higher torques are required with dry spindles to achieve the desired press-fit. This correlates with Peter's recommended bolt torques for Campagnolo cranks with dry spindles - Peter recommended a torque that exceeds Campagnolo's maximum torque specification by 10% (Peter recommended 30 ft-lb, while Campagnolo specifies a maximum of 27 ft-lb).

[Red Tornado]

Very interesting reading on a topic I thought I would never hear of again. This question will be answered immediately after the "which is better: Shimano or Campagnolo" debate is finally settled.
My $0.02 is.....
Originally started riding with Shimano & Suntour stuff. Installed dry, to middle of mfr's specs, never had a problem with squeaks or removal. Later on, switched to Campy and installed dry and torqued to mfr's specs. Stayed quiet for the first few rides then creaking got louder & louder. Took it to shop, they removed cleaned & re-installed - same result a few rides later. Rolled the dice & purchased a new crank & BB and had it installed by shop to Campy specs. Same result. I will add the wrenches at this shop were/are very knowledgeable/capable/experienced with Campy.
Out of desparation I removed the crank, cleaned everything and reinstalled with a very light film of anti-sieze on the flats & torqued to the min specs. Everything stayed in place and stayed quiet. This particular crank/BB combo lasted 7 years through several removal/cleanings/re-installs and when I sold to a buddy kept going strong and may still be going.
I still have an old MTB with Truvativ square taper crank/BB that's 10+ years old, installed dry, still going strong.
Not very scientific, but what happened with my Campy crank's/BB's is what happened.
All bikes now (except for the old MTB) are either ISIS or Campy Power Torque so not really an issue for me......

[oldpotatoe]

Crank manufacturer usually recommend upper and lower limits of bolt torque. Generally, the lower end of the torque range will work with lubricated spindles.

As noted previously, higher torques are required with dry spindles to achieve the desired press-fit. This correlates with Peter's recommended bolt torques for Campagnolo cranks with dry spindles - Peter recommended a torque that exceeds Campagnolo's maximum torque specification by 10% (Peter recommended 30 ft-lb, while Campagnolo specifies a maximum of 27 ft-lb).

I'll look it up but I think it's 26-ish to 28-ish. Too hard to see on my torque wrench so line on 30 ftlbs, craftsman beam type.

[jimbolina]

Not to drudge up bad energy, but this thread has interested me immensly, as I am dealing with a situation that has compelled me to obsess on a bit and this information found here has hit the spot.

I have used Campagnolo Record and N Record components for decades. I continue to exclusively do so. I love the parts, know them well and enjoy working with them. I have recently built up a NOS (aluminum) frameset and have installed my N Record BB onto said frame. I pressed on one of my Record cranksets as well.

As it has been some time since I've had to service any of my bikes, especially the bottom brackets, I have noted the current thinking has changed a bit on mounting cranksets with lubricant vs dry.

With that, I installed this latest assembly using a thin film of oil and am now second-guessing my actions. My fear is I used the old '80s Campy recommendation of torque value (between 28 and 32 ft lbs - dry) and settled on the middle 30 number, as I usually do, and now worry if these lubed surfaces may have allowed an over-torquing of my beloved crank arms.

I carefully read through this entire thread and found the argument to a mount the crank arms WITH lubricant quite compelling, but can not help but worry about possibly damaging my components, as described above.

What do you guys think about my situation? Are those torque values mentioned well within a 'safe' range, with or without lubricant, or is there some cause for concern?

[rustychisel]

My opinion is that you may be overthinking it slightly.

All cranks will fret over their lifetime, which is finite in any case. This is due to metallurgy, removal and installations, creeping and spalling. As it is I'm sure there's a margin of tolerance in installation within which you safely operate (according to your abilities as you mentioned).

I have more than one pair of 35 year old Sugino cranks, and so far they're just dandy.

[oldpotatoe]

Not to drudge up bad energy, but this thread has interested me immensly, as I am dealing with a situation that has compelled me to obsess on a bit and this information found here has hit the spot.

I have used Campagnolo Record and N Record components for decades. I continue to exclusively do so. I love the parts, know them well and enjoy working with them. I have recently built up a NOS (aluminum) frameset and have installed my N Record BB onto said frame. I pressed on one of my Record cranksets as well.

As it has been some time since I've had to service any of my bikes, especially the bottom brackets, I have noted the current thinking has changed a bit on mounting cranksets with lubricant vs dry.

With that, I installed this latest assembly using a thin film of oil and am now second-guessing my actions. My fear is I used the old '80s Campy recommendation of torque value (between 28 and 32 ft lbs - dry) and settled on the middle 30 number, as I usually do, and now worry if these lubed surfaces may have allowed an over-torquing of my beloved crank arms.

I carefully read through this entire thread and found the argument to a mount the crank arms WITH lubricant quite compelling, but can not help but worry about possibly damaging my components, as described above.

What do you guys think about my situation? Are those torque values mentioned well within a 'safe' range, with or without lubricant, or is there some cause for concern?

30 ft-lbs on a dry spindle for all square taper Campag(and other ST) cranks. Been doing this for 30 years on my and many customer's bikes and have never had a crank arm come loose or fall off.

[Mark McM]

Did you mount the cranks with excessive bolt torque? Don't follow Peter's recommended torque value - it exceeds the manufacturer's recommended torque rating. If installed with lubricated tapers, use a torque rating closer to the bottom end of the manufacturer's recommended range. If you did not over torque the crank bolt, your cranks should be fine.

[oldpotatoe]

Did you mount the cranks with excessive bolt torque? Don't follow Peter's recommended torque value - it exceeds the manufacturer's recommended torque rating. If installed with lubricated tapers, use a torque rating closer to the bottom end of the manufacturer's recommended range. If you did not over torque the crank bolt, your cranks should be fine.

Less than 2ft-lbs, my mark is on 30, beam torque wrench.

[Mark McM]

Less than 2ft-lbs, my mark is on 30, beam torque wrench.

But why did you have to exceed the maximum limit at all?