JohnDThompson 

I use a beam-type torque wrench.

sd5782 

I have a couple beam type torque wrenches as I don’t trust the other types. I was actually quite surprised how much one has to crank on the wrench to get up to 20 ft/lbs on a crank. That is a whole other discussion about torque needed. I use the torque wrench only on BBs and nothing else on bikes. I also use seldom on cars and motorcycles anymore since it has been a long time since I needed to do head bolts.

My observation is that just cranking down with a 3/8” ratchet won’t get it very tight, and even with 1/2” drive ratchet, ones needs to lay into it pretty good. I use the 1/2” and crank pretty hard and then out comes the 3/8” torque wrench. I am always amazed how much more I have to tighten. I am kinda afraid of splitting the arm so I stop at 20 ft/lbs. I ride it a few miles and recheck and don’t crank it down much if loose; just a good snug up with the 1/2” drive and then discipline myself to leave it alone.

Murray Missile 

While rare, beam type wrenches CAN go out of calibration and I have experienced it. I loaned out my beam type that came with the Craftsman toolset I got for HS graduation in 1973 once and only once, it came back with the needle noticably off zero. A casual hobbyist might not notice if the needle was off, it's usually caused by misuse or improper storage. However, judging by your previous posts I think I'm safe in assuming you are not a "casual hobbyist" and neither misuse nor store yours improperly.

I only have clickers now, I was doing mostly automotive work then so I replaced my beam type with a clicker as there were situations where seeing the wrench while torquing was next to if not totally impossible. As I needed wrenches of other ranges I bought more clickers. Now if I was to purchase a wrench strictly for bicycle work where I have it on a stand and can position it wherever I needed I would definitely go with beam type BUT.... as I have a few hundred dollars invested in the ones I already have from my motorcycle and vintage car days they'll "have to do do".

cyccommute 

On the few I own personally (like 2) I torque them to 35 ft-lb (~45Nm) and never touch them. Never had one come loose.

dddd

Best is to strictly adhere to the crank maker's prescribed (non-?)lubrication of tapers, washers and threads, ...and of course their torque specification.

I seldom use a torque wrench on square-taper crank bolts, but will re-tighten once after simply jumping on the pedals back and forth one time to effect forward/reverse torsion on the square tapered press-fit.

With nutted spindles (having coarser, larger-diameter threads made of relatively brittle material), I use a bit less torque on the nuts, but will repeat the tightening and jumping on the pedals three times so as to prevent the crankarms loosening. Using Loctite on nutted spindle studs is also a great idea, supplementing the toothed, directional scalloping on the nut's integral washer face.

I've had a crankarm loosen during a short CX race, so I use Loctite on all crank bolt threads for racing off road.
Off-road riding/racing incurs much greater torsion on the tapered interface, leading to greater chances of the bolt losing tension.
Heavier riders incur relatively larger spindle torsion under all riding conditions, so also may benefit more from use of Loctite on crank bolt threads.

52telecaster

Working in a bike shop with torque wrenches I was quite surprised at how tight crank bolts are supposed to be. Mine are put on tighter nowadays. Rarely recheck though.

Andrew_G

I think that the crank bolt torque settings are dependent on whether the bottom bracket axle is greased or not, and also whether the crank bolts are greased, or not.


I recall reading that for Campy (Nuovo) Record cranksets, the instructions said to degrease the tapers and the crank bolts, and install the crankset with no lubrication on those surfaces.

Campy's 11/1996 installation instructions for the crankset states: "Remove any possible traces of grease from bottom bracket spindle tapers before installing cranks." Also shown is the crank arm torque spec is 32-38 newton-meters (23.6 - 28 foot pounds). The BB bolts, as supplied by Campy, are dry and have a bit of painted-on locktite which adds to retention friction.


A Campagnolo supplied 1994 (bicycle) owner's manual also states to check the tightness of the crank after the first ride. The manual also states to "carefully clean the crank aperture" before reinstalling the cranks. The same 32-38 N-m torque spec is shown here, also.


Phil Wood's current instructions fo their "square taper bottom bracket" say to follow the manufacturer's instructions. However, Phil Wood also says to grease the BB axle tapers with Phil Wood grease before installing the crankset (https://cdn.shopify.com/s/files/1/03...s_V1.2.pdf?354).


What I do for crank installation:

I'm using a Phil Wood BB on all of my (3) bikes. I choose to oil the BB axle tapers; I put on a couple drops of Phil Wood oil, rub it around, and then finger-wipe off the excess. I also oil the crank arm bolts. I then install the crankset and torque down the BB bolts using either a Campy 15mm BB wrench, or another wrench of similar length. After the crank arms are installed, I then remove the BB axle bolts, clean them, and I also wipe clean (with Qtips) the axle threads. I then reinstall the bolts and torque them down by hand. I don't have a torque wrench.


My intention is to have a smooth installation and minimize any sticking or galling of the surfaces.


After crankset installation, my first ride is at moderate pace on relatively flat ground: I don't want to stomp on the cranks and possibly distort the tapers (if that's possible). On that first ride, I check the crank arm (ie, BB) bolts several times. To tighten the bolts, I just firmly lean on the end of the wrench. On my last crankset installation (only a couple of days ago) the cranks seemed to settle in and the bolts stopped loosening up after about an hour of riding. I'll check the bolts again on the second ride, but I usually find that after the cranks have seated, the bolts usually stay put.

repechage

I have had ONE arm exhibit radiating cracks at the tapered bore. Now, this was a pair of cranks and pedals sold to me for $15 in 1974 from a 1971 bike. The pedals were fused to the cranks. Seller perspired profusely. Campagnolo of course. I cannot argue 50+ years onward.

I did not read prior to Mark's post about lubricating the spindle taper... I will attempt to remove any assembly grease from the taper with my fingers. No rag, but only the most thin veil of lubricant, where the spindle appears dry basically.

grease them up and you will need to re-torque.

I have used a torque wrench once, as a comparison to what I do. A positive confirmation.

bulgie 

Then you are using grease on your tapers! Unless you degrease with solvent or detergent, any grease means greased tapers. Even a thick wad of grease gets squished out until there is only the thinnest of films, so your method is just the same as the thick wad of grease method, other than the thick wad making more of a mess.

I have heard a bit of lore repeated over the years, that the oil you get on your finger by rubbing your nose, then aplied to the spindle, is the right amount of lubrication. But any lube means lubed! You're also getting moisture off your nose, so I wouldn't actually recommend this method. Though I can't say from personal experience, it sounds wrong to me to intentionally put water in that interface.

OK, but when will that happen? Hasn't happened yet, but I've only been doing this for 50 years, and like they say, "past performance is no guarantee of future results".

This argument is evergreen, and it will never be settled, but I just want people to know that there is controversy, with experts on both sides. I know for a fact that both dry and greased tapers can work reliably when done by an experienced mechanic. I'm not trying to win anyone over to my "side", I know my anecdotes aren't data and I haven't proven anything. But neither have the dry tapers people — most of whom are using grease whether they know it or not!

Mark B

Germany_chris

I don’t re-check and I’ve not had one come loose

Sorcerer

Related, how far does a typical square taper move inboard as it is mounted in contact with the spindle until seated at proper torque?

​​​​​​Does that distance vary between different cranks?

And how does that relate to torque?

The result does affect chain line, especially on single speeds.

C9H13N 

I use grease and make them really tight the first time (1/2” drive ratchet, I don’t own a peanut butter wrench and don’t want one). I don’t re-torque, don’t even check, and always stand “goofy footed” on the pedals (it’s what feels normal to me).

Have never had a crank I installed come loose.

I’ve seen it happen to friends, in every instance on modern low end Shimano MTB cranks assembled by a bike shop (owners should have checked apparently).

oneclick 

Next time you put one on, count how many turns after it's snug; each is 1mm (bolt) 1.25mm (nut).

repechage

why just mere molecules of grease.
a taper fit depends on the engagement friction, why sabotage the design?

repechage

melt forged, low strength.

Pompiere

The Park Tool chart I have recommends 305-435 inch-pounds. My 3/8 torque wrench only goes to 250 inch-pounds, so that is what I use. Whenever I am tightening a crank, 250 inch-pounds feels like I should be worried about breaking something, so that is probably as tight as anybody would make it if they were not using a torque wrench. I do not recheck the cranks after riding and they are still tight when I take them apart later. I have a 1/2 inch torque wrench, but it starts at 25 foot-pounds(300 in-lbs.), so I question the accuracy that close to the bottom of the scale. I wipe the grease off the spindle with a rag, but I'm not using a solvent so there may be some residue.

jethin

I lightly grease the spindle, use about 3/4 of my very manly, very virile strength on the bolt, take a ride somewhere, and then re-tighten. The bolt usually moves a snug.

I suspect I don’t use the prescribed torque in the bolt, and my bet is that the prescribed force is excessive for safety concerns or something similar. Never had a problem.

My best guess would be that a torque wrench is a tool that belongs to a Monkee.

TugaDude

Sugino has a recommendation that bolts should be tightened with a regular wrench first. Then, after tightened, a torque wrench is used to ensure proper installation specs. They have more details here:

https://www.suginoltd.co.jp/us/pdf/T...nChart(EN).pdf

Trakhak

Thanks for that link!

From that page: crank axle bolt---40 to 50 Newton meters (29.5 to 36.9 foot-pounds, or 354 to 442 inch-pounds); crank axle nut---40 nm.

Trakhak

The mention of titanium bike parts brought to mind a tip concerning titanium bolts (and aluminum bolts, such as Cinelli 1R stem bolts). To install a lighter (and weaker) bolt while avoiding failure of the bolt during assembly or out on the road, use a steel bolt to tighten the fitting to the torque spec and then remove the steel bolt and install the lower-strength bolt.

In other words, the torque required to keep the assembly correctly tight (once the proper installation torque has been reached with the steel bolt) is lower than that specified for initial assembly.

steelbikeguy

With my Phil titanium BB, no titanium bolts were included, so no chance to try this technique... and I'm not sure that I would use them anyway.
I do recall some of the lightweight bolt kits, like Arnold, and have heard the recommendation to use steel bolts when forcing the cranks onto the axle.
The Palo Alto bike shop catalog listed a wide selection of aluminum bolts and parts....




A friend gave me some of his vintage bits, including some Cinelli style stem bolts that he had made. Really impressive, both in weight and craftsmanship. I can't imagine being brave enough to trust your teeth and face to an aluminum stem bolt, though. I think I sold one or two to a friend building up a weight weenie bike, and may still have one or two sets.



Steve in Peoria

79pmooney

If I were going to ride an alloy stem bolt I'd start with the original steel, tighten, back off and replace with the alloy. Swap back BEFORE knocking the plug not out to remove the stem.

sbarner

I recall reading that very same advice many years ago, and I think it was in some Campy documentation. I suspect I would have dismissed it otherwise. As I recall, it was worded something like "Wipe the tapers and then apply light lubrication. The oil from the side of the nose is sufficient." That's what I have been doing ever since!

What I wonder is what are considered correct tightening torques for vintage cranksets. I don't recall ever seeing a published spec from most manufacturers of vintage cranks -- did Stronglight even consider torque spec a thing? I'm in the dark even for a Campy Nuovo Record torque spec, and I'm a bit leery of anyone else's "educated guess" as being more authoritative than that for which I have developed a feel using my trusty peanut butter wrench. If I knew manufacturers' torque specs, I would use them. I'm often surprised when doing automotive work how much more I turn a bolt when I torque it after I thought I had already gotten pretty close with a regular wrench.

I did have the misfortune a few years ago of having a Campy left arm work loose on a ride. I'm am quite sure I installed it the same as I have been doing for decades, but the crank had a long, unknown history before I got it. I have read much of what Jobst wrote on the subject over the years and now clean the threads and apply Blue Loctite. If the bolt never loosens up the arm will never develop play. As these aluminum parts age I expect they get even more susceptible to cracking, and I think overtightening and/or re-tightening is not a wise strategy.

rccardr 

HA! I see what you did there…

bulgie 

Huh, it never occurred to me that an aluminum stem-quill bolt needed any special treatment. Been using them without issue since the '70s, as have generations of pros. Never heard of one breaking, have you?

I have seen cracks in an Arnold Industries crank fixing bolts, the gold-anodized ones. Seen two that cracked, both in the head in a way that didn't cause the shaft of the bolt to break. Just sorta like one-third of the hex starting to come off, what would that be called, a chordal crack maybe? Anyway a mellow failure mode, the bikes stayed rideable with the crack there. One was installed by me so I know for sure it was torqued with a steel bolt first. The alu bolt cracked from just maintaining the crank on the spindle. So it can happen.

That didn't stop me from using alu crank bolts though, too much of a weight-weenie. On my wife's bike anyway. She likes having a light bike and accepts there are some compromises. Me, I'm fat, so obsessing about the weight of crank bolts is not something I indulge in anymore. But back in my racing days, sure.

Mark B