Author Topic: Adjusting EBB  (Read 3354 times)

mickeg

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Re: Adjusting EBB
« Reply #15 on: July 26, 2023, 02:47:59 pm »
I've had good luck over the years by lightly greasing my square-taper BB spindles and then torquing them to spec ONCE. I don't re-torque nor do I lubricate the underside of the bolt heads. My general approach is summed up nicely here...
https://www.renehersecycles.com/to-grease-or-not-to-grease/#:~:text=They%20advised%3A%20%E2%80%9CGrease%20the%20tapers,press%2Dfit%20between%20the%20parts.

Best, Dan.

Thanks for posting that link.  I might start using grease on square tapers.

I have known people that kept tightening their crank arm bolts.  And I have noticed that crank arm bolts seem to be looser after a while.  But I have resisted the urge to keep tightening them. 

I have assumed that the crank arm was slightly stuck on the spindle and that the bolt was in tension pressing on it.  And with repeated pedaling, the arm would slowly slip further into place, reducing tension within the bolt, as the stresses in the components come into equilibrium with each other.  I have no clue if that actually happened or not, but when I could not figure out why crank arm bolts felt unusually loose later, I tried to figure out why.  And the slipping crankarm on a spindle was the only logical answer I could conjure up.

I was afraid that if my suspicion was correct and the crank arm shifted on the spindle, repeated tightening of the bolt could do more harm than good.  That is why I did not keep re-tightening them.

And, if I use grease on the taper, it is more likely to slip into place and stay there when first installed is my thinking. 

I will keep using a thread locker on crank arm bolts.  I recall a friend telling me that he was out for a bike ride and suddenly he heard someone swearing loudly.  This was in the days of toe clips, not cleats on shoes.  He looked at the guy swearing and he saw him on his bike, with a toe clip holding a pedal on his shoe, and a crank arm hanging loosely from his foot, no longer attached to the bike.  I do not want a crank arm bolt to fall out and get lost.  Or that could happen to me.

If I grease the taper, I wonder how much less torque I should use on my Campy cranks?  (No, I am not asking you to research it.)  I would be inclined to reduce it ... 20 percent.

I took a snapshot of part of a page of the Campy instructions, attached.  I have not bothered to de-grease, but otherwise this is what I have been doing.  (If you think this is a copyright violation, please delete it.)

martinf

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Re: Adjusting EBB
« Reply #16 on: July 26, 2023, 04:01:12 pm »
No more self extractors for me.

I tried self extractors a few years ago, as I thought they would be a good idea on tour.

They worked a few times, but finally one got stuck, so I had to remove the self extractor and use a normal extractor tool.

So I stopped using self extractors.

Except on very long tours, I don't bother carrying a crank extractor tool.

I don't think I have ever needed one while on tour since I started using square taper bottom brackets (the old cotter pin bottom brackets were another matter).

And in most places I go to it should be possible to find a bike shop with the necessary tools if I ever do need to remove a crank.

JohnR

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Re: Adjusting EBB
« Reply #17 on: July 26, 2023, 07:02:56 pm »
Continuing the subject of cranks, I wonder if cranks fitted in cold weather might need tightening in hot weather as aluminium expands more than steel? Also, I usually find I need to retighten the cranks after the first ride or two but I'm probably not using enough brute force as I use a big L-shaped Allen key.

mickeg

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Re: Adjusting EBB
« Reply #18 on: July 26, 2023, 08:10:22 pm »
..., I usually find I need to retighten the cranks after the first ride or two but I'm probably not using enough brute force as I use a big L-shaped Allen key.

At home I leave a 8mm allen wrench on my half inch drive torque wrench, as the vast majority of times I used that torque wrench, it was for crank arm bolts.  I think the handle is about 15 inches long (~~375mm).


PH

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Re: Adjusting EBB
« Reply #19 on: July 26, 2023, 10:33:41 pm »
Ha, I didn't mean to set us off on another path to perfection, I sometimes laugh at myself for overdoing it, though I'm greatful to those who make my obsessions seem reasonable!
I've never put a torque wrench on a crank, I don't have one that goes that high, I put a bit of copperslip on and do it up pretty tight.  The objective is for it to stay on till it needs to come off, then do so without drama.  So far, so good.

mickeg

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Re: Adjusting EBB
« Reply #20 on: July 27, 2023, 03:17:46 am »
Ha, I didn't mean to set us off on another path to perfection, I sometimes laugh at myself for overdoing it, though I'm greatful to those who make my obsessions seem reasonable!
I've never put a torque wrench on a crank, I don't have one that goes that high, I put a bit of copperslip on and do it up pretty tight.  The objective is for it to stay on till it needs to come off, then do so without drama.  So far, so good.

Years ago, soon after I built up a bike with a square taper, probably almost two decades ago, I heard a slight squeak as I pedaled.  Stopped, tried to find what was loose.  I was miles form home.  I only had a tiny little multi-tool but it did have an 8mm allen wrench, figured out that one of my crank bolts needed tightening.  I had read of a few cases where people rode too many miles with a loose crank and ruined them, so that scared to into doing a better job on that bolt.

Soon after that in 2006 I bought a 2003 Land Rover Disco 2.  That came with a receiver hitch from the factory, but mine was first owned by a rental car company.  They do not like people to pull trailers, so they pulled off the hitches and discarded them. 

So, I had to buy a pretty expensive replacement hitch to bolt to the frame.  And that had torque specifications that I wanted to make sure I did it right, so I bought the big torque wrench to install the hitch.  I learned that I did not need that torque wrench because lying on my back on the ground trying to tighten the bolts I learned that I did not have enough muscle to reach the required torque levels.  But I did the best I could.

So, that is why I use the torque wrench on those bolts on crank arms.  I want to do it right, and for another project I had already bought the wrench, all I had to buy for the bikes was an 8mm allen wrench that fit on a half inch drive torque wrench.

There is only one other thing on a bike I am careful on torque.  I have a Ritchey Break Away bike, that has a coupler similar in function to an S&S coupler on the downtube.  And the coupler has to be tightened to 4 nm of torque, no more, no less.  It uses a 4mm allen wrench.  So I bought a much smaller torque wrench for that.

Everything else, I do by feel.