SurferRosa

After mounting arms on a square taper bottom bracket and tightening the bolts, do you retighten once after a short ride, or do you leave them alone?

If you retighten, what's that "short ride" look like? Is a hill involved?

seagrade 

As much as I have been susceptible to overthinking bicycle mechanics methodology and application of The Knowledge over the years, all I've ever done with crank bolts is recheck tension, and retighten if necessary, after the first ride and thereafter from time-to-time.

From time-to-time I've found things needed minor retightening after first ride.

I've never given any thought to the topography or intensity of a test ride, other than to throw in a few sub-max sprints.

ThermionicScott 

Just like the lug nuts on our cars, I like to at least go around the block and re-check the torque before taking the vehicle any further. The nice thing about a beam torque wrench is that it's easier to see how far short of the desired torque you are when checking. If the bolt has become really loose again, I'll pull it back up to the target torque, but if there's a decent amount left, I'll stop a little shy, since some torque loss is to be expected when the crank seats onto the taper.

SurferRosa

I retighten once. My "short ride" is up a steep hill a half block long, and that's pretty much it.

The reason this is pertinent for me right now is that I overhauled a couple new-to-me bikes recently, and three of the crank arms had deformed tapers, probably from over-tightening.

rccardr 

Never re-tighten, have never had a bolt/arm get loose, either. Nor a wheel.

Mr. 66

I'll re tighten, if I can remember I'll bring tools and check on the ride. I've made the mistake of not and roasted a taper or two.

oneclick 

"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.
[...]
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."

(Attibution should be unnecessary.)

JohnDThompson 

I check the torque. If it's down from the installed torque, I snug it up. Otherwise, I leave it alone.

SurferRosa

Interesting vote count so far...

bulgie 

I don't retighten, don't even check, because I've never seen a need to. Never had one come loose. I'm not saying this is advice for others, but it has worked for me.

I think I tighten them tighter initially than most people do though. I don't know, since I've never used a torque wrench, but I'll bet I'm overtightening according to the manufacturer's spec. I don't use a tommy bar or cheater, just the normal 6 or 7" long wrench, but with close to all my might. I figger if a peanut butter wrench was good enough for Tullio, it's good enough for me.

This has never split or wallowed a crank for me, despite my use of <gasp> grease on the tapers. My chainline comes out OK, though I'll admit I never measured it with a micrometer. If I had to guess I'd say my cranks might go on a half-mm further than at recommended torque, but I'm OK with that. I like low-Q.

Maybe this would cause problems on a cheap/weak crank, like I dunno, Maxy? I have stuck with better brands like Campy Record, Dura-Ace, Stronglight 93/99, TA Pro, Mavic, Specialized. I have broken 3 cranks, two TA and one Campy, but not at the square taper. Twice as many TA cranks as Campy probably because I used TA on MTBs versus road only on Campy. Maybe TA cranks are weaker as well, I dunno, but the MTB abuse could be enough to explain it. I raced Norba Expert class (hard pedaling) and competed in Observed Trials (hard knocks).

I frequently took the cranks off for cleaning just because it's easier than cleaning in-place when they're grimy, so some of my cranks have been off and back on many times.

Mark B

clubman 

I've had so few 'loosenings' that I've chosen to err on tightening once. And as a confessional, rarely with a torque wrench

Mark beat me to it.

79pmooney

I said "No, ...". Sometimes I will re-tighten once if I'm not sure I actually got it right the first time but just that once. I've read what oneclick quoted (post #7) from several sources and I have always found a hard ridden crank will not be up to to torque when I check it. I did split a crank years ago and consider that the lesson from that was yes, what oneclick posted is what happens.

And yes, I've heard supposedly good mechanics tell folk that checking those bolts for torque is good practice. I keep my mouth shut because that's an argument I'm not going to win and just walk away a little sad and hope the advised forgets.

Soody

Brandt's take on this issue has always infuriated me. He doesn't actually explain what to do about the problem. So, crank arms can squirm up the taper, you lose preload of the bolt, retightening can damage everything, what do you do about it?
He's writing I guess as an iconoclastic person discussing the issue with others who know what they're doing but now his piece has taken the place of a near definitive guide. I suspect he had a conflict of interest as avocet sold left crank arms or something.

ThermionicScott 

That's precisely why I adopted the "middle way" of checking the torque that I described a few posts up. Use the torque wrench to check if the bolt is seriously loose, but if it's not, don't keep retorquing the full amount, since that can damage the crank.

Soody

Yep that's basically what I do too. Check it's snug. Not trying to drive it on further but just hand right down by the socket on the wrench give it a little push. For 5 rides maybe.
1/20 maybe require this. I also frequently see this failure happen on other people's bikes. Correct installation with attention to cleaning the surfaces, light grease, and adequate torque is the main thing.

I think the reason this advice isn't mainstream is that it isn't viable for a bike shop to do or to instruct. I've lent a wrench out to people that i've rebuilt bikes for with these instructions but it's very tiresome giving customers any instructions or chores unless they're both your friend and a nerd. I'll try to test ride bikes i rebuild a few times to do this but riding the very small ones sucks.

Trakhak

If you're talking about a bike with a conventional tapered spindle that you (or a previous owner) bought new from a bike store, chances are that the crank bolts were tightened during the 90-day tuneup (or whatever wording was used) that the bike manufacturer required the dealers to offer. Aside from safety checks (brake checks, etc.), I always thought of the torquing of the crank bolts as the most important part of the tuneup.

I suppose it's possible that some of the left crank arms that we sold to customers were needed because the original crank was over-tightened at some point, but I'd bet that most were sold to people who had never bothered bringing the bike in to get that first tuneup.

Handy tip to anyone installing a crankset with a tapered spindle: grease the threads of the crank bolts and then use a calibrated torque wrench on one crank and a standard socket wrench on the other to tighten the two crank bolts simultaneously. When you hear the torque wrench click, both bolts have reached the correct tightness.

steelbikeguy

I've always just tightened once... until..

There was the time when I bought a Phil titanium BB to use on a Campy Record crankset. i.e. the classic late 70's/early 80's Nuovo or Super Record crankset. I thought I'd replace the Campy BB with a lighter Phil BB. I contacted Phil to be sure that the axle taper was suited for the Campy, and they assured me it was. I installed it as typical, and did a few rides. Unfortunately, I was in the middle of a ride when I discovered that one (or both?) arms were a bit loose! I was close to one of the LBSs, and they snugged the bolts up. No issues after that.

My guess is that there was enough difference in the taper of the Campy axle and the Phil that the aluminum arms had to yield a bit before they fully contacted the axle taper. That, of course, meant that the bolts were no longer tight, and the crank arms were free to move around and deform the aluminum.

I had a chance to test this hypothesis when I bought some SunXCD cranks (clones of the TA Cyclotouriste) for a bike. I wasn't sure what BB to use, but had a Specialized cup & cone BB that looked like it was suitable. Since both the crank and BB were made in Japan, I figured that it should work. The test fit seemed fine. Still, for the first few weeks, I'd check the bolt torque after each ride. The first few rides did need a bit of additional torque, but after that, there was little or no change in bolt tension. A couple of years later, and no problems.

In my experience with good quality cranks that fit the axles, there shouldn't be any need to recheck bolt torque. On a brand new crank, it wouldn't be a bad idea to go check a few times, though.

Steve in Peoria

BFisher 

Never went back to re-tighten a crank arm and have never had one come loose. Never cracked or otherwise damaged a crank arm, and yes, I grease my tapers.

BoltBreaker

If I'm gonna break a bolt, it'll be a seat post binder bolt most likely. But BB crankarm bolts are set 'n forget. Unless they creak... then they get a re-torque.

nlerner

Too modern for me; I’m sticking with cottered cranks.

Sorcerer

It wasn't until eBay where I have purchased some crank arms that loosened, and one that cracked open around the taper.

I sort of attribute this to the adage: You get what you pay for.

However, I have bikes with used cranks from eBay on them, mostly White Industries, that I ride hard on a regular basis.

Anyway, used stuff, and pre-owned, is a bit of crap shoot.

That said, until I bought cranks on eBay, I was in the install them tight, and after a ride or two only snug up the crank bolts until they stay on (below threshold) thereafter, using only a 7" long spanner (Park tool).

This is how I was taught from an old Schwinn bikes shop when I was a kid. I never questioned it.

The paradigm seemed to be that the crank bolt wrench handle length would prevent over-torque.

[ I was at the same time told not to grease the tapers.]

Then one day I had the experience of a creak that wouldn't go away, and as a last resort I retorqued the cranks, and voila, the creak went away. It was a single speed.

At the moment I am lost in the fog on the matter. After some recent related experience with PF30 bottom brackets I have become a firm believer in torque wrench usage.

Love square taper stuff as much as I love 27.2 seat tubes.

I'm no expert on this matter. This is my experience.

SurferRosa

Down the back stretch .... is No pulling away?

Can Yes come back?

Will Something Completely Different make up some ground?

​​​​​​

Andrew_G

I find that after crankset installation, I have to retighten the BB bolts several times, until the crank seats. After it the crankset settles in, the bolts stay put.

After initial crankset installation, I do an easy break-in ride on gentle terrain. I don't want to distort the tapers (if that's possible) by pounding on a crankset before it's fully seated.

I completed a crankset installation break in ride yesterday, Friday Jan 13. The crankset was an IRD Defiant (made by Andel in Taiwan) mated to an appropriate JIS taper Phil Wood BB. The BB bolts seemed to settle in after an hour of riding.

I get similar results when using a Campy 9/10 crankset mated to a Phil Wood BB (with Campy spec tapers).

bwilli88 

I tighten at least one grunt, no torque wrench here, then go for a short ride, come back and use a rawhide mallet and give the crank arm a few good whacks, then snug up again.

Murray Missile 

Question for all the torque wrench users, How often do you have your wrenches checked for calibration? Continue at your own risk.......

Testing torque wrenches used in a manufacturing facility was part of my old job for about 15 years, Around 300 of them and all different brands and types. A personal observation from doing thousands of tests on a half dozen or so different brands used in an industrial environment: If you have an older Proto, MAC or US made Craftsman and don't substitute your torque wrench for a breaker bar or hammer you're probably fine for a few decades. If you have a Snap On get it checked occasionally. If you have a cheap Chinese wrench you really don't want to know........ Of all the brand name consumer grade wrenches the company used Snap On were the only ones we had to remove from service for being out of calibration and it was usually within a year to 18 months. Snap On doesn't warranty tools used in a manufacturing facility either. To save money they tried buying the Chinese cheapies through McMaster-Carr and Grainger. Those had an 80% failure rate right out of the package and the few that passed the first time rarely made it past 6 months at which point the ratchet heads were usually slipping anyway. The best were the industrial grade wrenches from Beloit, Belknap and anything with Sturtevant and/or Richmont as part of the name but they are $$$ so it's doubtful too many home shops will have those. Kudos to anyone that does have any though, GOOD STUFF!