Installing cranks

Hey guys,
When im installing my cranks, the bolt that thread into the BB, do i have to tighten this up using a tool or is hand tightness fine?also do i use grease or threadloc?

tool other wise the cranks are not drawn into the bb properly, when you say grease you mean for the crank bolt? a tiny bit would be good but not too much

Grease on the bolt or nut that tightens the crank arm on the spindler: yes

Grease on the sqare taper of crank arm or spindle: basically NO!
With the prescribed torque, the crank arm will slide too far over the spindle, leaving a permanent deformation of the crank arm's square taper.

Only exceptions where you can (or shall) use grease between spindle and arm:

• splined BB spindles like Octalink, ISIS
  
• RH (drive) side of square taper Shimano BB axles with a so called "chain line stabiliser" (= stopper ring) on the spindle
  

there's lots of conjecture about whether to grease the spindle arm before you push the crank on
personally i would add a little tiny bit of grease to basically make it easier when removing and stop the buggers rusting / oxidising together

definately spanner tight when doing it up thats all that holds the crank arms to the spindles, you don't want that connection coming loose while going breakless down ditchling beacon now do you !!

Tighten the bolts (with a resonable amount of force, but I would'nt 'put my weight into it'). Ride the bike a few times and retighten. The cranks work their way up the taper after a couple of rides because of the torque on the bolts.

@Dutch Cheese.
@dicki.
Where do you guys stand with regards to greasing titanium spindles. I read somewhere that this was one of the 'dont grease square taper spindle, exceptions'. I think it has something to do with titanium and aluminium chemically weilding. I recently reinstalled my cranks after a typical hunt the creaking noise mission. I decided to wipe off (just with a greesy rag, so not washed as such) the anti seize I had used during the original install.

Hey guys,
When im installing my cranks, the bolt that thread into the BB, do i have to tighten this up using a tool or is hand tightness fine?also do i use grease or threadloc?

Are you serious?
Do you think hand-tight is going to support your weight for more 3 or 4 revolutions of the crank?

Tighten the fuck out of that bolt, then get someone who knows what they are doing to have a look at it just in-case.

I'm definitely pro grease.
I was told it, I've seen mechanics do it, and I've never damaged a crankset.
But the way I do it is- liberal grease, and then use a cloth to wipe away basically all of it, so that there's still a layer of grease, but its very fine.
It definitely aids removal, and is a life saver if you are using the stronglight crank extractor.

Tighten the fuck out of that bolt.

I snapped a crank bolt doing this (although on the second, after ride, tighten).

Thats a pretty unpleasent experiance if you treated yourself to a ceramic/titanium BB for xmas. Managed to drill two tiny holes in what was left of the bolt, screw in two small screws and use them as leverage, to remove the bolt from the BB.

Having said that. I agree with you for the first installation. I'd just advise caution on the second tighten (especially if you've used some grease).

liberal grease, and then use a cloth to wipe away basically all of it, so that there's still a layer of grease, but its very fine.

Man, it was good to read that. I've got a seriously expensive crank/BB set-up, now installed like this. I feel I've done a good job, but a tiny part of me wants to degrease the spindle.

I assumed a modicum of common-sense and included the epithet for emphasis , didn't mean for the OP to jump up and down on the Allen-key.
Judging by the first post may have been a mistake though, rocker has probably drafted in the Ukrainian weightlifting team to take turns on that fucker.

That said, I have only ever tightened the crank-bolts on my bikes once, then ridden them.
Never had any problems with bits falling off.

[INDENT]From Sheldon Browns site (with my exact feck up underlined). According to this, tightening the f**k out of the crank bolts during prelimary intallation is absolutly the thing to do. TBH I lucky I only fecked up a crank bolt.

I now just remove any loosness in the bolts after the first couple of rides, without using much in the way of force.
[INDENT]
[/INDENT]

*The admonition not to grease the spindle finds life mainly in the bicycle trade. When I discussed the "dry assembly" rule with crank manufacturers, I discovered that they had warranty claims from customers who split cranks. However, cranks cannot be split by overtightening them. This can be proven by attemting to do so. An M8x1 bolt is not strong enough to split a major brand crank. *
*Failure from "over-tightening" is caused by repeated re-tightening of properly installed cranks. In use, an aluminum crank squirms on its taper and, because the retaining bolt prevents it from moving off the taper, it elbows itself away from the bolt and up the taper ever so slightly. The resulting loss of preload, after hard riding, can be detected by how easily the bolt can be turned. *
*Loss of crank bolt preload is greater on left than the right cranks, because left cranks transmit torque and bending simultaneously while right cranks transmit these forces separately. The left crank transmits driving torque through the spindle to the right crank and chainwheel while the right crank drives the chainwheel directly. Besides that, the right crank transmits torque to the spindle only when standing on both pedals. Doing this with the right foot forward (goofy footed) is the only time the spindle transmits reverse torque. *
*Mechanics, unaware of why crank bolts lose preload (and commensurate crank tightening), have re-tightened bolts until cranks split. No warnings against re-tightening properly installed cranks are evident although it is here where the warning should be directed rather than at lubrication. *
*Because friction plays no role in torque transmission, preload in the press fit must be great enough to prevent elastic separation between the crank and spindle under torque and bending. This means that no gap should open between crank and spindle facets under forceful pedaling. Crank bore failure occurs when the press fit is loose enough that a gap opens between spindle and crank. Torque is transmitted by both leading and trailing half of each facet, contact pressure increasing and decreasing respectively. In the event of lift-off, the entire force bears only on the leading edge of facets and causes plastic deformation, causing the bore takes on a "pin cushion" shape (loose crank syndrome). Subsequent tightening of the retaining screw cannot correct this because neither the retaining bolt nor crank are strong enough to re-establish the square bore. *
*The claim that a greased spindle will enlarge the bore of a crank and ultimately reduce chainwheel clearance is also specious, because the crank cannot operate in a plastic stress level that would soon split the crank in use. However, increased engagement depth (hole enlargement) may occur without lubricant, because installation friction could ream the hole. *
*With or without lubricant, in use, cranks will make metal-to-metal contact with the spindle, causing fretting erosion of the steel spindle for all but the lightest riders. Lubricating the spindle for assembly assures a predictable press fit for a given torque. Without lubrication the press is unknown and galling (aluminum transfer to the steel spindle) may occur during assembly. After substantial use, spindle facets may show rouge and erosion from aluminum oxide from the crank, showing that lubricant was displaced. *
*Crank "dust caps" have the additional duty to retain loose crank bolts. Because crank bolts lose preload in use, they can become loose enough to subsequently unscrew and fall out if there is no cap. If this occurs, loss of the screw will not be noticed until the crank comes off, after the screw is gone. Jobst Brandt *

[/INDENT]

damn smallfurry.....
grrrrrr.

damn smallfurry.....
grrrrrr.

:)

http://www.parktool.com/repair/bikemap.asp

I worked in a bike shop for a few years and never had any problems with an over-tightened crank bolt (though I'm sure it can happen). Every week we would have to replace cranks that were ridden when loose and had been rounded out though. Tighten them hard and keep an eye on them.

Sugino 75 BB tapers come with a light grease film already on them.

You probably want to tighten them to about 80% - 90% of your strength with your hand about 10-15cm down allen key or rachet. I found that this gave about 30nm torque*

I would not 'go for it' on a larger rachet as although it probably won't cause any problems / damage in use it will be harder to get off.

*completely subjective

@Dutch Cheese.
@dicki.
Where do you guys stand with regards to greasing titanium spindles.

Never, ever use Ti BB spindles.
I've seen several people with serious injuries on their calfs because of failing BB spindles, especially Ti ones.
Forget about lightweight in the first place.
Certainly on track, fixie and SS it doesn't matter at all.

If you want lightweight, there are better ways, e.g. oversized steel spindles. Better and lighter than Ti.

Never, ever use Ti BB spindles.
I've seen several people with serious injuries on their calfs because of failing BB spindles, especially Ti ones.

Wow. I was under the impression that Ti was seriously strong. Although, come to think about it, I know little regarding its use as a BB axle.

The BB in question is one of these with ceramic bearings, titanium coated races, and a titanium axle. Its waaaaay over the top for my usage, but I was about to buy a campag pista BB, when I spotted this for the same price (well less infact, due to duty dodging).

Especially Campag Ti spindles tended to break.
Ti is very HARD, not exceptionally strong.

Especially Campag Ti spindles tended to break.
Ti is very HARD, not exceptionally strong.

Do you mean Titanium Nitride is hard? I believe the strength of titanium to be similar to steel also?

haven't there been pictures where the centre of a crank has bust off as it gets tightened up way to hard
torque wrench - is that a must in a good bike tool kit ?

Ti is very HARD, not exceptionally strong.

This what I was wondering about here...

Although, come to think about it, I know little regarding its use as a BB axle.

Knackers, my left crank fell off.

Again :(

I few months back I put in a new BB and cranks.

At first I did it with no grease but after a while it started to make creaking noises as I pedaled up hill, like a squeaky mattress. So I took em off and lubed them up with a little grease.

This fixed the squeaks, but I think I did not tighten enough. After a few weeks the left side worked itself loose. I tightened it up before it fell off. A week later it worked itself loose again and fell off after a few hundred metres - despite trying to pedal as softly as I could with my left foot. (Funny what you do rather than have to get off and walk the bike home!)

So re-tightened & it got me about 4KM and now it is loose again. I think it is screwed the square hole is starting to get rounded corners - feck...

Anyone know where I can get hold of a single NOS Sugino Max crank?

Lessons learnt

In future I would use a little grease and go for the tighten like fuck approach.

Also, must get and remember to carry a suitable pocket tool for roadside repairs.

get a torque wrench or borrow one, tighten to correct torque, forget about it.