jimmuller 

One non-obvious thing not mentioned here (unless I missed it) but discussed by Sheldon Brown is that you should never stand on the pedals with them horizontal and the right pedal in front. Always stand with the left pedal in front. The reason is that pressure on the left arm always torques the left crank forward w.r.t. the spindle and the spindle forward w.r.t. the right arm, but pressure on the right arm doesn't torque the spindle joints at all. When you stand on the pedals right-arm-forward it reverse-torques both joints and will tend to loosen them, eventually ruining the arms' taper.

rhm

Well obviously there is such as thing as taking things too far.

I understand the proper technique for installing a crank, tightening it once a few days later, and then it's trouble free, stays put until it's time to service the BB, and then comes off with the usual ease. But then there are cranks that don't play by the rules.

It's quite an unusual item, first generation Dura Ace, 160 mm arm, anodized blue. Another forum member gave it to me and I really like it. It's now on my fixed gear Bottecchia that's set up for randonneuring. I installed the crank by the usual method, as described elsewhere in this thread. Out on its first long ride, 100k, the crank came loose. It was seriously wobbling. I tightened it and kept riding. Five miles later I stopped and tightened it again. I may have done that one more time before I got home. I then commuted on it for a week. Getting ready for the next brevet I noticed the crank am was slightly loose. Very slight. I tightened it.
The next day I rode it on a 200k brevet and had no more trouble. If the crank proves hard to remove, I will try to remember why.
Ideally we want to tighten a crank just enough that it doesn't get loose from normal (or even fixie) riding. In cases where the crank tapers are slightly damaged, it is possible to find that level of tightness. This may be poor practice, but when I'm dealing with a crank that is probably irreplaceable, it's no good to tell me it's a lost cause. I'm going to make it work if I can.

​​​​​​I kinda doubt I'm the only one with that attitude.

merziac

Exactly this, you and I will decide whats best for you and me.

repechage

I have not installed the two VO cartridge bottom brackets I recently purchased, but did note upon opening the boxes that the spindles are plated and pretty smooth, not showing machining marks.
Most spindles of the day from many if not all European mfgs, and upper tier offerings from Sugino, Shimano, SR show traces of machining marks or grinding and often no plating on the surfaces.

I use the verbal directions from the 70's Campagnolo pro support van, circa 1975, the tapers should receive only the bare minimum amount of lubrication, essentially the film left by your fingers trying to remove it, there will be a thin film of Campagnolo grease remaining, (what else was there for race bikes in the 70's?)
OK, there was Phil Wood... The ports of the cranks should be dry.

I will use a torque wrench today, the spec I did find later was 45Nm as being correct.

I will have to report later after install and some service time.

jiangshi

Campagnolo recommends no grease/lube on the tapers. Dry fit.

repechage

Took a bit to recall the name, Bill Woodul was the USA Campagnolo support guy in the 70's.

merziac

Merz was good friends with Bill, here's a great pic from Jim's FB page.

https://scontent-sea1-1.xx.fbcdn.net/v/t1.0-9/33858_163002420382662_6754835_n.jpg?_nc_cat=101&_nc_ht=scontent-sea1-1.xx&oh=b216f2bd1c2987874954d6d0d43907ca&oe=5D40D4EF

tiger1964 

From the Velo Orange website: "Classic square taper design JIS taper - works with most cranks". Hmm, I wonder what the impact is here and what cranks will or will not fit it? I really like the BB and would possibly even swap the crankset before the BB.



This bike came to me, looking unmolested, with a Campy BB. Taper difference?



Interesting, and the bike came without them. This is the only Avocet crankset I recall seeing -- but doing a Google image search, there were indeed dust caps. I presume I could use another brand.



IMHO, somewhere in between, The bolts that came with the VO BB are indeed washerhead, but smaller outside diameter that I would expect, I usually see a washer that pretty much fills the opening, these are smaller.



Ouch. I wonder how long the cranks will survive. Without removing the crank, a quick estimated measurement suggests even optimal "contact depth" of spindle and crank arm is 19mm or 20mm, so 7mm to 8mm of non-contact is significant.



I see Avocet spindles on eBay, but it means abandoning the sealed BB I just installed.



+1 right now on Loctite-and-wait. Probably cannot ride again until at least Tuesday due to weather, so I need to make a decision and act.



Sounds like picking up a Campy cranks... won't help. What cranks -- I fear asking this -- use JIS?



I recall seeing the same. Very slick mounting surfaces.

tiger1964 

Also, from the website titled "Sheldon Brown": "Note: Old Ofmega/Avocet spindles were quite a bit skinnier/longer even than ISO. There are no modern bottom brackets that work with old Ofmega/Avocet cranks." And yet it worked for years on a Campy spindle.

noglider 

@jimmuller, I don't follow. Are you saying never stand on your right foot? So then what, sit down when it's time to pedal with the right, or just pedal more gently? Or something else?

bark_eater 

Just going to throw some anecdotal's in the pot. I've had 2 bikes, which are my most ridden, that have had problems with cranks loosening. Both have Shimmano cranks and the same type of "Tange" bottom bracket. It looked to me that the the bottom bracket spindles are not "pointy" enough, so the small part of the taper is digging into the crank taper socket. One crank had to be tightened repeatedly and now has a bit of a chain ring wobble. The other held tension after 3-4 snugging and is holding. The wobbly one held for 500s mile or so but last month when I was getting it back on the road I was lubing my chain with Break-Free. there was a little corrosion on the spindle, so I gave it a little squirt for good measure and went for a ride. I ended up having to do the last mile one legged because the left crank had Broken-Free.

jimmuller 

Oh, I pedal with only one foot.
The problem isn't with pedaling. It is with standing to raise yourself off the saddle while not pedaling. The force of your right foot is taken up by the chainring and chain when pedaling. That puts no torque on the spindle. But when you stand while not pedaling the force is taken up by the other leg through the spindle. If the right leg is forward it puts a reverse torque on .both spindle joints.

noglider 

OK I have to take some time to observe myself. Do I stand with the right pedal forward? Do I even stand at all without pedaling? I will see.

JohnDThompson 

For the first year or so (1977? 78?), Avocet branded Ofmega cranks used Ofmega-spec spindles that tapered down narrower than other spindles. But later production for the North American market used Campagnolo-copy taper:


Source: Sutherland's 4th Edition

noglider 

This gives me a new appreciation for Shimano's two-piece cranks. Mechanically, it's better, but it sure is ugly.

repechage

But, what of the IRD cranks, and associated brands, (Holdsworth) where the square port sides are not on the bias? Having the sides are aligned with the length of the arm?

noglider 

Great question, because I can't guess what the answer is. Has IRD said what their rationale is for that weird design?

jimmuller 

It took me a while to figure out what you are asking! Actually I have two VO Gran Cru Drillium cranks which from appearances are like the Holdsworth, but I don't recall the hole orientation. The orientation may make them stronger, but I dunno'.

Anyway, the point about standing on the cranks (with the arms horizontal) is about which direction the spindle/arm joints are torqued. That would be the same regardless of the hole orientation. During pedaling the right arm's force goes directly into the chainring, and the only torque on both spindle joints is the dead weight of the left leg. The force of the left leg pedaling is transmitted to the chainring by applying torque to the spindle which then applies it to the right arm. So both joints are subject to significant pedaling torque in only one direction. Sheldon's point was that when you stand on the pedals with the left leg in front you torque the joints the same way as pedaling. When you stand with the right leg in front you torque them the opposite way. This has the effect of helping them generate relative movement, never good in a joint that is supposed to be tight.

Salamandrine 

Virtually all modern square taper cranks that I know about use JIS. Sugino! SunXCD, VO, etc etc. Vintage is a different thing. Vintage Stronglight is pretty much exactly the same as JIS also, except they used a longer spindle than most Japanese cranks. 118 for double? I forget. TA is pretty close too - close enough.


Campy stopped making taper fit cranks AFAIK. They were ISO after ISO became a thing in the 90s. Before, in the C&V era, they were in between, but closer to ISO than JIS. (See chart above)


Frankly most cranks were in between BITD. A lot of try and fit went on, but still, they were generally considered all interchangeable unless proven otherwise.


At any rate, you have to make a choice IMO. Get a new crank that fits your new BB, or cut bait and get a new BB that fits your cranks.

merziac

So, were track cranks structurally completely different and how did the many road versions relegated to some kind of track/fixie duty survive en masse literally to this day?

Not questioning your logic, seems like something Sheldon or Jobst would have weighed in on, maybe I missed it but IME have seen very little fallout that points in that direction.

repechage

merziac

That was essentially my point as well, like I said, the logic seems sound, the data to me does not seem to support it from what I have seen.

jimmuller 

I have no idea what track cranks did or do. As for Sheldon weighing in, in my first post on the subject in this thread I said it was something Sheldon has claimed. So yeah, he did!

The torque direction would certain be true, no question. That it induces micro-movement in the joints makes sense. Whether it really hurts them in practice, that's a different question.

I sometimes stand on the pedals to see over traffic or shrubbery when commuting, more so in the old days than on my current commute. I never thought about the direction until two thing happened. I started hearing little squeaks when doing so. I was told, don't recall by whom, that those crank arms were ruined, could never be fixed. Fortuitously I happened on the Sheldon article shortly after that and put two and two together, started standing in only one direction. The squeaking stopped and I'm still using those crank arms.

To this thread's original point, I did try tightening the bolts but it didn't stop the squeaking. I do not keep re-tightening them on any of my cranks. I was taught, either by book or Sheldon or word of mouth, to tighten to spec (I was told 22 ft-lbs), ride for 30 miles re-torque, then leave them alone. That practice has worked well for me.

tiger1964 

Well, the deed is done. 30ft/LB and thread locker, once I found the blue thread locker; at first all I could find in the garage was red (!) and green (?)

'll try a test ride tomorrow and NOT try to retighten; I guess if something is irreparably wrong the 1st indication is a crank coming loose, likely as not when I'm furthest from home.

I'm going to skip the standing up while still discussion, I don't think I do that, except maybe a second while pushing off from a stop? I don't even stand on the cranks much while ascending.

100% - if I change cranks, I want a C&V solution, preferably with the sealed BB however. Who else besides VO makes those?

I need to look up who IRD is.

Checking VO's website, their own cranks are JIS but the sets all come with teeny chainring counts, would have to buy and then buy yet more chainrings $$$.

Like I said, I have some 93's, if the chainlink ends up "off", maybe ad a spacer under the fixed cup while checking that the LH crank still clears the chain stay.

Well, if I want Campy it's Record, maybe Super Record, no modern stuff... that's the point, eh?

The chart is interesting and obviously is not depicted in MY copy of Sutherland's: 1974

Yeah, back when I rode in the 1970's, and worked in shops, I do not recall any "taper issues", just left to right spacing was a little different on French cranks. Times change!

I'll start looking. I wonder how long these cranks will hold up -- maybe forever, no idea. I've ridden maybe 150 miles on this crank/BB combo, was hoping that the retightening might cause JIS-ification of the Avocet cranks and all will be well. But it's probably more likely that is won't.[/QUOTE]

tiger1964 

And this bike is supposedly 1980 vintage. I can look at the cranks for date markings (Avocet?)