Airburst

Yesterday, whiile riding my Saracen MTB, I noticed the cranks creaking whenever I pressed down on the left-hand pedal. I didn't think anything of it at the time, but when I got home, I decided to try a quick test. Pushing the left pedal down fairly hard with the left crank pointing forward made the crank creak once, but then it didn't do it again until I pressed the cranks the other way, I.E left-hand crank pointing backward, hold right-hand crank and press down on left-hand crank. Again, it only creaked once, until I turned the cranks through 180 degrees and pressed again. Each time it creaks, I think the cranks move ever so slightly relative to each other (about half a degree, I reckon). Correct me if I'm wrong, but does that sound like one of the cranks is loose? They're fairly old Shimano Alivio cranks, the bottom bracket is a cartridge one, and I've had the bike several months with no problems from them. Any suggestions as to why this is happening now, and more importantly, how to stop it?

Thanks in advance

DannoXYZ 

Remove the crankarm.
Clean the taper on the spindle.
Clean the hole in the crank.
Put a drop of oil on each flat of the taper on the spindle.
Re-install crankarm
Tighten crankarm bolt to the proper torque using a torque-wrench.
Post on here what torque-reading you used.

Go test bike, no creaks!!!

redtires

If that doesn't fix it, it also may be the bottom bracket. Once you have the cranks off, you may as well pull it and do some "house cleaning" in your bottom bracket shell...it's very good preventative maintenance.

kenl666

I'm pretty sure that lubricating the flats of the spindle is a big no-no. Torquing the crank arms on to spec should be sufficient to prevent any movement (which is what causes the creaking noise).

Once the cranks are on securely, any creaking may be coming from the bottom bracket. My lightspeed had a BB creak, I finally got rid of it by removing and cleaning the threads on the BB and the cartridge. When I reinstalled, I greased the BB threads and also applied plumber's teflon tape to the cartridge threads, then torqued it to spec.

Woodwind314

Actually, not lubricating the spindle square is the big no-no. Without lube, tightening torque measurements are pretty much moot. Even worse, the fit between spindle and crank will be considerably looser w/o lube at a given torque. This will be most pronounced with used/old cranks and spindles with corrosion-caused increased roughness of the surfaces.

I would recommend using a (salt)water resistant heavy grease rather than oil; the grease will help in preventing corrosion between spindle and crank which is the most common reason for stuck cranks.

Fears that one could damage or even split cranks by tightening are unfounded; long before that you'd strip the threads of the tightening screw.

But even with lube, proper tightening and in the absence of corrosion, the hole in the crank will get deformed over time by fretting damage. If creaking and measurable movement of the cranks on the spindle cannot be remedied anymore by cleaning/lubing/retightening, the cranks likely are toast.

Dan Burkhart 

Oh goody, a square taper grease/no grease thread. Haven't had one of those in a long time.

Woodwind314

I wasn't aware there was any serious discussion potential in that....whatever lube one puts in there, the forces created by pedaling are high enough to replace any lubricant in a short time, resulting in metal-to-metal contact. There is not even theoretical room for lube induced problems on that joint. (As opposed to quill stems!)

Chop61

Oy Vey. Barnett's says no grease. Here we go!

Dan Burkhart 

You're new hereabouts, aintcha? It's one of those discussions that often takes on religious tones. Both sides have true believers.

Jeff Wills

Yep. I greeza, you no greeza, all-a-same-ee. Can't we all jus' git along?

mrrabbit 

Let loose the dogs of war!

=8-)

fietsbob

I'm in the grease the bolt , not the flats of the spindle group,
what color gang uniform do I wear?

Dan Burkhart 

Has anyone ever thought to ask a tapir if they like to be greased?

DannoXYZ 

The grease versus no-grease battle never ends. One major manufacturer recommends grease. Their main competitor, another major manufacturer recommends no-grease. I split the difference and use oil.

Woodwind314

True, I'm new to this forum. Sorry for fanning religious flames!

I come from background with boats, and there are some rules cast in iron. One of them is: Any junction between metals, especially different metals, either gets greased or gets destroyed by corrosion within a few years.

As I happen to ride my bike in the winter too, everything there will get some salt water exposure....When I bought my current bike (used), I didn't take everything apart. That was a mistake - 2 Years later I wanted to change cranks...no luck. Had to cut off the BB spindle. After hammering out the stumps from the cranks, one could see thick layers of white aluminium oxide everywhere in the junction. Proof enough for me.

Note that the grease is not there to insulate the 2 materials, but rather to prevent water from entering the junction.

powitte

Try it without grease. If it stops the creaking, good. If not, try some grease/oil and reassess ?

DannoXYZ 

Sure you can do that, and in many cases, you end up having to do this operation twice, once without and once with. The grease really is not a substitute for no-grease installation, but rather is an addition to the no-grease for more out-of-spec or severe usage. For example, most of the time in most bolted interfaces, one does not need a lockwasher. And it works most of the time under the intended loads. However, in many cases, and in cases where higher safety is required, a lockwasher and safety-wire is specified. This will not change the operation of the joint in any way, but mitigates against those rare and out-of-spec instances. Such as racing cars or motorcycles.

So the grease on the taper is for cases that are out of the ordinary. It doesn't hurt normal operations in anyway, but if you have an installation with salt-water, or if manufacturing tolerances are on the loose or out-of-spec range, then the grease deals with those instances. I've seen many crank+spindle combinations that simply do not work as intended. Brand-new out of the box crank and spindle will creak or come loose even with the bolt tightened to specified torque (using more than specified torque is not a solution). In those cases, extra steps are needed, such as grease to help the out-of-spec taper on crank & spindle mate better. Or a star-lockwasher + Loctite in cases where the bolt works loose even with proper torque.

Also kenl666 pointed out another area that causes creaks, the BB in the loose threads of the BB-shell. Although airburst's test of hopping on the crank and rotating 180-degrees (rocks the crankarm back & forth around the spindle), indicates it's more likely the crankarm-to-spindle interface.

rwhite2

I bet a greased tapir race would be similar to a greased pig race. Could the organizer of a greased tapir race be called a "tapir race setter"?

kmv2

Check your if everything is tight, especially chainring bolts (nobody mentioned that??)

Hold each pedal and try to move them not rotationally but axially/radially to see if there is play which would suggest a loose bearing cup or worn bearings.

The noise will probably not manifest itself with just your hand pressing down, as the force of your foot is many times greater, but you will be able to get feedback and feel if anything is not as it should be.. that being noticeable radial and axial play.

Grease or no grease, check the mechanical state of the components first.

Woodwind314

Indeed! Often overlooked....Yesterday I changed cranks back from compact to my normal 52/39, adjusted the FD, everything is as smooth as can be, but riding I get these strange noises from time to time...and I can't put power on in the big chainring, chain starts to rub the FD....what the f***?

Back home I put the bike in the stand only to discover the chainring bolts are all completely loose. I simply forgot to tighten them at all!

531phile 

I do this with grease instead of oil. Rule of thumb to get rid or noise: clean, oil/grease, and tighten to spec

davidad

https://draco.nac.uci.edu/rbfaq/FAQ/8f.11.html

kmv2

Its something I often find loosens over time if you dont use some sort of threadlocking compound (which I would not recommend even if it prevents the problem because its not always easy to fit that special chainring screwdriver on and get a good hold on it).

Anyways, that IMO is usually the cause of creaking in the BB/crank area.

kenl666

I wasn't aware that there was such a big brouhaha regarding the issue of whether or not to grease the crank spindle flats, so I did some research:

Sutherland's Handbook For Bicycle Mechanics 6ed pg. 2-4:
"The spindle end and the hole in the crank must be clean and dry. Do not use oil, grease, or an anti-seize compound. The tapered square system depends on the crank coming up firmly on the spindle. Any lubrication will cause the arm to go on too far in tightening or to float on the spindle... Grease or anti-seize compound may be used on the threads of the crank bolt."

Barnett's manual of Bicycle Repair pg. 20-11:
"...prepare the arm for installation by cleaning the mating surfaces of the spindle and arm with acetone or alcohol. The purpose of this is to remove any traces of lubricant. Since these two pieces are held together by friction, grease or oil may enable the arm to go on further (not necessarily a good idea)... Crank manufacturers are unanimous in recommending against lubrication of the spindle when mounting the arm."

Zinn & the Art of Road Bike Maintenance, 3ed, pg. 210:
"With square-taper spindles, clean off all grease from both parts with a rag and citrus-based solvent. Greasing the axle may allow the soft aluminum crank to slide too far onto the hard steel or titanium axle and could deform the square hole in the crank."

Big Blue Book of Bicycle Repair, pg. 68:
"Aluminum cranks typically do not require lubrication of this press fit. Aluminum by its nature is covered with a thin layer of oxidation, which acts as self-lubrication... If a crank creaks even at full torque, remove and grease the pressed surfaces."

Jeff Wills

Hmmm... good selection of quotes there, but in my 30 years of working on bikes I've never had a crank deform to point of uselessness when the flats are lubricated and the bolt torqued to spec. I've seen plenty ruined due to insufficient torque, though, but that's been because of lack of correct tools or mechanical training.

As Danno said above- lubricant helps if the interface isn't perfect. If the tapers on the crank and spindle were a perfect fit, then there would be no problem. However, manufacturing tolerances being what they are I'd say that a bit of lubrication is prudent.

(Gonna do RAO? George and Terri put on a heck of an event.)