[steel515]

Should square tape bottom bracket tapers be greased/oiled? I thought I read they should not have any grease/oil. But I saw one bike store greased my spindle. Is the grease to prevent seizing?

 

[Argentius]

Not really. I don't know what the grease is for.

Theoretically those who say "no grease" don't want the crank to slide on the axle, but many people do it and it doesn't seem to hurt.

 

[JCavilia]

Don't start this one!

This has been endlessly debated. There are passionate, experienced, fully convinced proponents on both sides of the issue. I say do it if you like the way the grease smells. It doesn't seem to make much difference. I grease (I may be a Phil Wood junkie.

 

[terry b]

Should square tape bottom bracket tapers be greased/oiled? I thought I read they should not have any grease/oil. But I saw one bike store greased my spindle. Is the grease to prevent seizing?

What do the crank/BB instructions say?

 

[MB4]

Parktool.com says it is not needed. Philwood.com says apply a little grease on the tapers. I've read some pretty good arguments for either side. Who knows? I got a Phil BB and greased.

 

[andreq]

I prefer to grease them. Helps everything to tighten up easier. Many don't grease but I have had cranks cease to the spindle before so now I always use grease. If you remove cranks lots it makes life easier and if you do the crank bolts up to torque there will be no problem with loosening

 

[cthomas]

I also grease

Just a very light coat of marine grease. Mainly for peace of mind so I know it is not a source of any noise (creaking).

 

[Dave Hickey]

I've never grease mine..tapered bb/crank is about the only metal/metal interface I don't grease..

I read years ago not the grease but in reality it probably doesn't make any difference...

 

[Spunout]

I religiously DE-grease taper and spindle surfaces. I find creaks go away after cleaning. Also, old-school reports of crankarms splitting and cracking have been attributed to greased tapers. It is not a moving interface, so why grease?

 

[andreq]

I grease for the same reason you should grease bolts. It allows the components to go together easier and reduces unecessary friction when torquing to required spec. Sure the taper/crank interface does not move neither does your seatpost but it is good practice to use some kind of lube there for ease of removal/installation. I dont have a problem with people not using lube on the crank taper and i never used to either but when I had a beutiful set of old xtr cranks ruined by being stuck to the taper I started using grease and have never had a problem since. It gives me peace of mind andmakes my life easier when working on my bikes.

 

[SamDC]

Should square tape bottom bracket tapers be greased/oiled? I thought I read they should not have any grease/oil. But I saw one bike store greased my spindle. Is the grease to prevent seizing?

If you're worried about galvanic corrosion but don't want to use grease because of the possibility of slipping, you might want to consider some medium (Blue) Loc-tite or similar thread-lock compound.

 

[spookyload]

This is the most heated and passionate debate next to the shimano/campy debate. The only down side I have heard is that the lubrication can lead to overtightening.

 

[VaughnA]

I read an article lately that indicated that campy recommended putting grease on the taper and then wiping it off, leaving a very thin layer. It indicated that if your hands were slightly greasy from working in the shop just wiping your fingers on the spindle would be enough to grease the taper.

 

[curlybike]

I always clean all taper crank mating surfaces with Brakleen and apply blue loctite to all flats of the spindle. Install crank to prescribed torque. Never have a creak. Never had a chainline problem. Never had an arm come loose AND NEVER HAD A PROBLEM REMOVING EITHER ARM. also never had any evidence of galling, fretting or corrosion.
What more can you want?

 

[Mark McM]

also never had any evidence of galling, fretting or corrosion.
What more can you want?

If you've worked at all with square taper spindles with appreciable mileage, then you have had to seen evidence of fretting. Many square taper faces have small residual "ridges" left over from the machining or grinding processing to make the flat face. After removing a crank after many miles of use, I'm sure you've noticed that some of these ridges have become worn down or smoothed off where they contacted the crank. This "wear" is due to fretting (micro-motions) between the crank and spindle.

No, this wear did not occur when the cranks were first installed. If you install the cranks to full bolt torque and then remove them, you'll see no indication of these ridges being worn down. The wear only appears after the crank has been installed and ridden for many, many miles. And this fretting wear occurs whether the crank/spindle interface was lubricated or dry during installation.

This fretting during use proves that, despite what the no-grease-on-the-tapers philosopy teaches, cranks do move on the tapers in use, even when installed without grease. The motions are very small, but after many, many cycles of loading, it does slowly cause wear on the spindle.

There is other evidence that cranks move on the tapers (even when installed dry). Have you ever noticed that, even when the bolts are torqued very hard during installation, that after riding the bike for a long time, the bolts take much less torque to loosen? No, the bolts did not unscrew during use. What happened was that as the cranks were loaded, and the crank/spindle interface was moving slightly (fretting motions), the crank "walked" ever so slightly away from the bolt (up the taper), relieving some of the pre-load on the bolt. That the cranked moved slightly up the taper during use is the reason that the bolts are easier to remove and the cranks are harder to pull off the taper after the bicycle has been ridden an appreciable distance.

Experiments have shown that when cranks are installed with grease, that the crank/taper fit is tighter after the initial installation, but that the cranks move less during use (at the same installation bolt torque). The reason to grease the tapers is to acheive a more uniform, tight fit during the initial installation, and allow less movement during use.

 

[terry b]

You'd think someone would have shared that information with Campagnolo, because page 18 of their crankset installation instruction pamphlet says, "Before you install the cranks on the bottom bracket axle, degrease the axle and the crankset square heads thoroughly."

Now I know that everyone here including me is far, far smarter than people who design and fabricate parts like this for a living. I mean, they're just bunch of dim, CYA engineers, and more than likely Italian engineers to boot. I'm sure the corporate legal staff is looking over their shoulders as well.

I'm a walking contradiction. Buy me a new DVR and I throw the instruction away, preferring to figure it out in my own. But when it comes to bikes, and my health, I tend to follow instruction. Now maybe Shimano is different, but I think our friends in Vicenza might have a different opinion.

(And yes I know, everyone has been greasing their square tapers since the days of Bobet and they're all still walking around to tell the tale)

 

[Eric_H]

A great battle

You'd think someone would have shared that information with Campagnolo, because page 18 of their crankset installation instruction pamphlet says, "Before you install the cranks on the bottom bracket axle, degrease the axle and the crankset square heads thoroughly."

Mark McM' reply is dead on. The important thing to note is that the crank will work its way up the spindle after it has been ridden hard. It is then subsequent torquing of the crank bolts that often leads to cracking of the crank at the spindle bore, because once the bolt has been tightened the crank will squirm its way up the spindle a little more. The best thing to do is install the cranks with a light coating of grease, use some blue loctite on the bolts, and torque them to spec. Then leave them alone until they have to removed.

Once again, I suggest reading some Jobst Brandt at the Usenet rec.bicycles.* FAQ:

http://draco.acs.uci.edu/rbfaq/FAQ/8f.11.html

I suspect Campagnolo's instructions are a result of the well-known failures of the older Campy Super Record cranks from the early-mid 80s.

FWIW, I install my Campy cranks with grease.

 

[terry b]

I suspect Campagnolo's instructions are a result of the well-known failures of the older Campy Super Record cranks from the early-mid 80s.

And somehow they've failed to update their instructions in these intervening 20+ years. Or bothered to do any follow-up testing.

Yet the compelling evidence of "experimentation" appears to suggest that it's a bad idea to install without grease and such an installation can lead to damage and failure. Funny that Campy just can't seem to get it together.

I find it really amusing when a bunch of hobbyists think they're smarter than people who design, build and sell this stuff for a living. I see it all the time in my work, not suprising that we as cyclists fall into the same trap.

In reality though, I think this topic is a classic case of cognitive dissonance. Ever since the first time our daddies put a wrench in our hands, we've been told you always grease a metal to metal interface. Along come these instructions that contradict that well-held value. We say "bah" and then go off and build a case for why we're right. Even to the extent of believing it because it's on the internet and because Jobst Brandt said so. Human psychology is an amazing thing. Yet in my case, in 20 years of building and riding I've had one crankarm come loose - the square taper that I greased. I'm sure that was because I failed to properly torque it.

 

[Eric_H]

From one hobbyist to another

And somehow they've failed to update their instructions in these intervening 20+ years. Or bothered to do any follow-up testing.

Yet the compelling evidence of "experimentation" appears to suggest that it's a bad idea to install without grease and such an installation can lead to damage and failure. Funny that Campy just can't seem to get it together.

I find it really amusing when a bunch of hobbyists think they're smarter than people who design, build and sell this stuff for a living. I see it all the time in my work, not suprising that we as cyclists fall into the same trap.

In reality though, I think this topic is a classic case of cognitive dissonance. Ever since the first time our daddies put a wrench in our hands, we've been told you always grease a metal to metal interface. Along come these instructions that contradict that well-held value. We say "bah" and then go off and build a case for why we're right. Even to the extent of believing it because it's on the internet and because Jobst Brandt said so. Human psychology is an amazing thing. Yet in my case, in 20 years of building and riding I've had one crankarm come loose - the square taper that I greased. I'm sure that was because I failed to properly torque it.

So you are then under the assumption that every single component in the Campy line has been engineered and tested to its maximum? Somehow I doubt it. The bike industry is filled with "engineers" who pass along gospel as fact and I'm sure there are a couple who exist at Campy. Jobst has his flaws, but he is a smart guy who rides his bike a lot and is also a guy who really makes an effort to understand the workings of bicycles from a fundamental level. I am not bashing Campy, I have a basement full of Campy with no Shimano left to be found. Here are some more examples of their instructions:

Bottom brackets - Campy says to install the cups without any grease. They have some form of thread prep on them already, but it certainly isn't grease. Once again, I coat those suckers with grease before they get installed. Installing those cups dry into just about any BB shell (steel, Ti, Al) seems to be risky.

Seat post clamp - Yes, a small part but on the asymmetrical clamp instructions they say to never lubricate the bolt or the threads. Again, I put grease on the bolt head and the threads. Unless I am putting Loctite on a bolt for the purpose of keeping it there, all threaded interfaces get grease.

In the end, I doubt grease or no grease really makes a difference on square tapers. The press fit pretty much squishes out any grease, plus when I remove cranks after many many miles, the tapers are bone dry and there is evidence of fretting. This is a debate, much like Campy versus Shimano, clincher versus tubular, steel versus carbon that has its people on each side.

 

[Mel Erickson]

I follow the instructions from the manufacturer. I figure they know their product better than anyone. I grease if they tell me to and clean if they say to do that. If the instructions are silent I'll probably grease if it's metal to metal and certainly on any moving part. So, what does the maker of your BB say?