Bicycle Mechanics - repeatedly installing/removing square taper cranks...

How many times can this be done? Does the crank begin to deform more and more eventually finishing the crank?

A normal amount of removal and installation shouldn't be an issue. I've got some XTR cranks that must be about 12-13 years old now, and still haven't given up the ghost (great, now I've jinxed myself ;)).

How many times can this be done? Does the crank begin to deform more and more eventually finishing the crank?

Why is this going to be an issue? You removing them and reinstalling them before you sleep each time? The more times you take it on and off the greater chance for damage, especially if you aren't using a torque wrench.

it only takes one bad installation to deform the crank - I know, I've done it.

but, as long as you do it right everytime, no problem.

I'll only be removing them a normal amount... for bb upkeep. Mainly I was just wondering when it would this would become a problem. I'd read that it can be a problem, but I was wondering if it takes.... 6-10 times? 10-20 times? you know like what ball park.

And yes I do use a torque wrench.

Why is this going to be an issue? You removing them and reinstalling them before you sleep each time? The more times you take it on and off the greater chance for damage, especially if you aren't using a torque wrench.

What is the proper torque value for a Campagnolo crank onto a Phil Wood bottom Bracket?

This is one place a torque wrench is good to have so that you don't broach the crank.I've torqued my SR crank/Shimano BB to 40 ft-lbs for the last 30 years,no problems.I've put in or serviced it about 25/30 times.

I torque them down,leave the cap off,ride around the block a few times,check again,put caps on.Then I check every few days a couple times,just to make sure.Cheaper than a new arm.

That's kinda overtightening it at 40-lbs. But you're more likely to cause damage by under-tightening them. All it takes is for them to come loose just once and you've buggered the square-taper hole and it'll never, ever fit right again.

I've found it's a lot more secure to replace the flat washer with a star-lockwasher if you're going to be removing the cranks a lot. Reduces the chance that a well-used bolt with worn threads may come loose. Usually a good practice to use new bolts every 10th time you've re-installed the cranks.

What is the proper torque value for a Campagnolo crank onto a Phil Wood bottom Bracket?

Going to have to ask you which campy crank you have.

That's kinda overtightening it at 40-lbs. But you're more likely to cause damage by under-tightening them.


No, by tightening them that much he's more likely to damage them to overtightening. Which he is doing by an extreme margin, already. 35Nm for square taper cranks with 8mm hex bolts is generally enough. And that is quite tight already



All it takes is for them to come loose just once and you've buggered the square-taper hole and it'll never, ever fit right again.


And all it takes is for one slide too far on the spindle if you overtighten.




I've found it's a lot more secure to replace the flat washer with a star-lockwasher if you're going to be removing the cranks a lot. Reduces the chance that a well-used bolt with worn threads may come loose. Usually a good practice to use new bolts every 10th time you've re-installed the cranks.

Bolts come loose because of inadequate torque. If you're really that worried about it coming loose treat the threads with loctite. Which really ins't necessary. Using a star washer only serves to damage the crank.

The better solution for the OP is to stick a cartridge bb and forget about having to regularly overhauling the bb and it's subsequent problems. Time to get with the 21st century.

I have the same crank arms on my 33 year old bike, and they haven't worn out yet (oops, now they will wear out next week for sure....)

You will effect the chain line each time you remount the cranks by moving it in a small amount. Amount depends on the crank and bottom bracket axle, as well as the torque. You will also wear the threads on the bolts and inside the axle. I suggest using DuPont Krytox on the threads and under the washers.
We travel with an S & S Coupled tandem. We got 20 trips in before the XT cranks became so worn that we could no longer use them. We don't apply lube on the crank axle square tapers but we do use a torque wrench each time to tighten the bolts.

You will effect the chain line each time you remount the cranks by moving it in a small amount. Amount depends on the crank and bottom bracket axle, as well as the torque.
I haven't found this to be the case on a wide variety of cranks square taper including SR, Sun Tour, Shimano and Campy. I remove them for bb maintainence and reinstall them to the proper torque ( I do lightly grease the spindle taper - a BIG argument in itself) and the chainline does not move at all.

I also have an S&S coupled bike so the 105 square taper crank has been off and reinstalled a dozen or more times. I've never had to touch the limit screws or indexing adjustment.

Well, your method seems to be a good argument for lightly greasing the tapers.
We did need to touch up limit screws and JumpStop adjustments every other trip. We didn't need to readjust the rear derailer.

There isn't a lot of BB upkeep to do with a Phil Wood. It might be 5 years before you have to do anything other than an occaisional retorque. bk

We travel with an S & S Coupled tandem. We got 20 trips in before the XT cranks became so worn that we could no longer use them. We don't apply lube on the crank axle square tapers but we do use a torque wrench each time to tighten the bolts.

If you only got 20 cycles of an XT crank, then you did something wrong. Seriously.

I've been a machinist for almost 40 years,and I can tell you for a FACT that 40# will not broach forged aluminum,even crappy forgings.It takes around 200# of force to push a broaching tool thru an aluminum forging to cut a 3/8 keyway,and the broaching tool has carbide teeth on it.ID broaching tools cut on a taper,just like BB's.Imagine how much force it would take to push a BB spindle thru a forging with NO cutting teeth on it.

35-40 Ft/lbs is NOT going to broach a GOOD FORGED aluminum arm,EVER.Were talking 10#-15# over the recommended torque that gets used these days,spread out over the surface area of the spindle(1 1/2-2 sq-in or so),that's nothing.

I'm sure most of the men on this site can push a 100# with their hands,anybody think they can push hard enough to broach the crank arm out?....What if I get a 400# guy to sit on the crank arm,think that will do it? My guess is that most the problems we hear about are from cranks that have come loose,egged out the hole,then the fun begins.

In 1978 when I bought the bike,the shop told me that's what the torque was,been using it ever since.It may be too tight for the "professionals",but my cranks never come loose and the chainline is still fine after 30 years,so I'm sticking with what works.If it last another 30 years ,I'll be dead,someone else will have to worry about it.

Also, older cranks may have nutted spindles, rather than bolted, and they generally appreciate more torque.

In the bigger picture, if someone's worried about this issue, there's always Hollowtech II or Octalink :)

if you use a torque wrench every time you install them, indefinitely

I use 27 ft lbs each time. 25 is the standard and 30 won't kill ya either

20 trips = 40 cycles as we re-stalled the cranks to ride around home too.
I am stating what I observed and experienced.
I can't give exact quantifiable data as to how much the chain line changed, but I know that I readjusted the front derailer stops and the JumpStop 10 times during the life of the crank. The cranks had around 52k miles and were replaced a couple years ago along with the bottom brackets.
We are now using Octalink BBs and cranks, so I don't see any movement in the chain line now.

I've been a machinist for almost 40 years,and I can tell you for a FACT that 40# will not broach forged aluminum,even crappy forgings.It takes around 200# of force to push a broaching tool thru an aluminum forging to cut a 3/8 keyway,and the broaching tool has carbide teeth on it.ID broaching tools cut on a taper,just like BB's.Imagine how much force it would take to push a BB spindle thru a forging with NO cutting teeth on it.

35-40 Ft/lbs is NOT going to broach a GOOD FORGED aluminum arm,EVER.Were talking 10#-15# over the recommended torque that gets used these days,spread out over the surface area of the spindle(1 1/2-2 sq-in or so),that's nothing.

I'm sure most of the men on this site can push a 100# with their hands,anybody think they can push hard enough to broach the crank arm out?....What if I get a 400# guy to sit on the crank arm,think that will do it? My guess is that most the problems we hear about are from cranks that have come loose,egged out the hole,then the fun begins.

In 1978 when I bought the bike,the shop told me that's what the torque was,been using it ever since.It may be too tight for the "professionals",but my cranks never come loose and the chainline is still fine after 30 years,so I'm sticking with what works.If it last another 30 years ,I'll be dead,someone else will have to worry about it.

The "ring" of truth. You know it when you hear it.

I want to know the appropriate torque because I do not want to break the bolt (too much torque) and I do not want the crank coming loose (too little torque).

About 22-25# is about what the manufacturers recommend. I usually go a little higher to 30# and haven't had any problems.

For the record, you can have a crank come loose on you and not ruin it, you just have to catch it early. There is a definite feel when the crank first starts to come loose, and as long as you catch is there, no damage will be done. Argue all you like, but I've felt my crank loosen (my fault, it was the one time i didn't use a torque wrench), but I caught it, pedaled home with 1 foot. When I checked it, the tapers were still fine.

I wouldn't recommend it, but just letting you know one loosen isn't death.

I'm sure some of the problems people have,is not their fault.Like Daveornee above,where he had his arm screw up after 20 times on and off.He probably did everything by the book.

If the taper angles don't match well when new,everytime you take the arm off and put it back on,the arm will recede on the spindle a tiny bit until the surface area is big enough to hold the forces involved.So then it ends up being a race between the arm receding and enough surface area on the mating surfaces on the tapers.Depending on who wins the race,determines if the bolt/nut bottoms on the end of the spindle or not.

Should one keep the same orientation of the crank arms on the spindles? In other words, should the arms go on in the same position as they came from? Does it even matter? I've always put mine on in the same location that they came from and never had any problems, in the 25 years of doing this, on my various bikes.

I've been a machinist for almost 40 years,and I can tell you for a FACT that 40# will not broach forged aluminum,even crappy forgings.It takes around 200# of force to push a broaching tool thru an aluminum forging to cut a 3/8 keyway,and the broaching tool has carbide teeth on it.ID broaching tools cut on a taper,just like BB's.Imagine how much force it would take to push a BB spindle thru a forging with NO cutting teeth on it.

35-40 Ft/lbs is NOT going to broach a GOOD FORGED aluminum arm,EVER.Were talking 10#-15# over the recommended torque that gets used these days,spread out over the surface area of the spindle(1 1/2-2 sq-in or so),that's nothing.

I'm sure most of the men on this site can push a 100# with their hands,anybody think they can push hard enough to broach the crank arm out?....What if I get a 400# guy to sit on the crank arm,think that will do it? My guess is that most the problems we hear about are from cranks that have come loose,egged out the hole,then the fun begins.

In 1978 when I bought the bike,the shop told me that's what the torque was,been using it ever since.It may be too tight for the "professionals",but my cranks never come loose and the chainline is still fine after 30 years,so I'm sticking with what works.If it last another 30 years ,I'll be dead,someone else will have to worry about it.

You seem to be intermixing torque (and the resulting clamping force) and simple force measurements. Force is pretty straight forward. What you apply is what you get. With torque, the actual clamping force will vary depending on the amount of friction that is encountered in the system. The friction can be in the threads, under the head of the bolt, or between the two items being press fit together (where applicable of course). For this reason, what is greased and what isn't and what's between the bolt and clamped member is (very) important.

I don't have the calculations here in front of me to demonstrate, but I can assure you that 30 ft.*lbs. of torque is applying a LOT more than 30 lbs. of clamping force though. It most certainly is applying a lot more than 100 lbs. as well. Ever try to push a square taper crank on by hand? It's not going to happen.

For a tapered press fit, you are relying on a certain amount of friction in the system to stop the crank arm from going too far down the spindle. Grease on the spindle and/or bolt threads will drastically affect the friction and result in a different press fit depth than if no grease was used on either component. Now whether that difference in friction and press fit depth actually harms anything is another subject. I don't have enough experience with square tapers and different assembly methods to say one way or another which is best. I never grease the spindle but I do grease the bolt threads and haven't had any issues yet (4 years and 20,000 miles on square taper cranks if you care).

I don't have enough experience with square tapers and different assembly methods to say one way or another which is best. I never grease the spindle but I do grease the bolt threads and haven't had any issues yet (4 years and 20,000 miles on square taper cranks if you care).
This is a VERY contentious issue but I've always lightly greased the tapers based on what a very experienced Mechanical Engineer explained to me about interference fits. I also haven't had any issues in 23 years and 125,000+ miles.

Conclusion: there is no clear-cut best-way to handle square taper cranks or one side would have shown a demonstrable advantage and the discussion would have been over years ago.

This is a VERY contentious issue but I've always lightly greased the tapers based on what a very experienced Mechanical Engineer explained to me about interference fits. I also haven't had any issues in 23 years and 125,000+ miles.

Conclusion: there is no clear-cut best-way to handle square taper cranks or one side would have shown a demonstrable advantage and the discussion would have been over years ago.

I haven't seen grease/no grease make a difference either way. You never have bikes come back with problems such as, "oh my crank fell off because the taper was/wasn't greased". Or "my taper is damaged because of grease/no grease". Etc.

I don't think it matters.

I haven't seen grease/no grease make a difference either way. You never have bikes come back with problems such as, "oh my crank fell off because the taper was/wasn't greased". Or "my taper is damaged because of grease/no grease". Etc.

I don't think it matters.
Right, that was my point. However for reasons known only to them, and never explained, Campy is quite adamant that their square taper bb spindles are NOT to be greased. Shimano doesn't specify either way. I've greased both makes and never had a lick of trouble.

Right, that was my point. However for reasons known only to them, and never explained, Campy is quite adamant that their square taper bb spindles are NOT to be greased. Shimano doesn't specify either way. I've greased both makes and never had a lick of trouble.

I find the matter quite interesting because ISIS spindles seem to require grease. Both ISIS cranksets I have bought have come with the ISIS recess thoroughly greased and the bottom bracket instructions have also been very clear about the requirement for grease. I wonder if it's just a precautionary of the part of the manufacturers given the relative newness of ISIS spindles (compared to square taper) and the fact that the encountered friction doesn't play any part in where the crank will end up on an ISIS spindle.

What's the recommendation for Shimano Octalink cranks and BB's?

The splined crankarms seem to require grease to fit fully onto the spindles. Without the grease, they tend to have more friction and bind up prematurely on the splines before going on correctly. This then fools the torque-wrench into thinking that you've got sufficient bolt-tension to hold. However, over time with riding, you'll wiggle the crankarm a little further onto the spindle and all of a sudden you've lost all your bolt-tension. This lets the bolt wiggle loose and eventually your crankarm will follow.

Also check the splines on both the crankarm and spindle for contamination. I've found that little metal pieces the size of a couple of grains of sand can cause the crankarm to catch and bind and not go on fully.

As for square-taper arms, I've done them both dry and greased without any problems Now I just use a little light-oil. Seems to ward off the creaking for longer.

Just so nobody gets confused,I'm not talking about clamping force,I'm talking about broaching a hole.Depending on thread pitch,clamping force will be roughly 100x the bolt torque.