# Ultegra crank left arm falling off



## usedtorace (Mar 13, 2015)

On a fast century ride two weeks ago with my brother (sub-5:15) two things happened at the 85 mile mark. A dog ran out in front of my brother and he nailed it and took a nasty spill and then about a half mile later my left crank arm fell off. The crank is Ultegra 6700--circa 2015. 

Disclaimer here--this crank was assembled by me according to directions and then checked at the shop in February with a torque wrench. I was told the plastic cap does very little to snug the arm down and that the two side bolts do all the work. 

What went wrong here? Was this catastrophic failure due to the significant pressure I know I put on the left crank arm to avoid toppling over my brother (I'm about 210 pounds)? I've never had a crank arm do this. Does the failure have something to do with improper position of the stopper plate? Are the cranks ruined? 

All the way around--the $180 I paid for these cranks was 180 too much--poor design.

Century time was still 5:14. We stopped the clock, I put the crank back on as best I could and my brother rode in all bloody and battered.


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## cnardone (Jun 28, 2014)

pictures? How did it fall off? did the bolt just shear off? Did the bolt screw off?


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## tlg (May 11, 2011)

usedtorace said:


> I was told the plastic cap does very little to snug the arm down and that the two side bolts do all the work.


The cap does nothing to hold the arm on. It's just for adjustment. You could remove it after the crank is tightened.



> Was this catastrophic failure due to the significant pressure I know I put on the left crank arm to avoid toppling over my brother (I'm about 210 pounds)?


No



> Does the failure have something to do with improper position of the stopper plate?


Probably. And/or the bolts weren't properly tightened (even though the shop said they were).



> Are the cranks ruined?


No way to know without inspecting them for damage.



> All the way around--the $180 I paid for these cranks was 180 too much--poor design.


Absolutely positively nothing wrong with the design. $180 is a good price for a good crank.


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## usedtorace (Mar 13, 2015)

tlg said:


> The cap does nothing to hold the arm on. It's just for adjustment. You could remove it after the crank is tightened.
> 
> No
> 
> ...


How would one tell if there is damage? So the bike shop probably messed up?


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## usedtorace (Mar 13, 2015)

cnardone said:


> pictures? How did it fall off? did the bolt just shear off? Did the bolt screw off?


I don't have pictures, but it fell off in such a way it was dangling from my shoe. However, I attached it back on as best I could and snugged it down while on the road and it held just fine. That makes me think the bolts got super loose somehow from my massive wattage.


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## tlg (May 11, 2011)

usedtorace said:


> That makes me think the bolts got super loose somehow from my massive wattage.


Only trolls posses enough wattage to loosen a crank.


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## usedtorace (Mar 13, 2015)

tlg said:


> Only trolls posses enough wattage to loosen a crank.


Just kidding dude. I'm an overweight former Cat. 3 cyclist with terrible power numbers. This probably had to do with my own improper assemblage and bike shop speedy check. I still think the design sucks.


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## bigjohnla (Mar 29, 2010)

Did you put loctite on the bolt threads when you installed the crank? I agree, there is nothing wrong with Shimano cranks. They are awesome and a great value.


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## Marc (Jan 23, 2005)

usedtorace said:


> I don't have pictures, but it fell off in such a way it was dangling from my shoe. However, I attached it back on as best I could and snugged it down while on the road and it held just fine. That makes me think the bolts got super loose somehow from my massive wattage.


Depending on the mode of failure, and the damage to any of the clamping surfaces in the process of failure....that crank may never stay fastened again. Needs looked at by someone who knows about such things to have any certainty.


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## usedtorace (Mar 13, 2015)

bigjohnla said:


> Did you put loctite on the bolt threads when you installed the crank? I agree, there is nothing wrong with Shimano cranks. They are awesome and a great value.


That's a great suggestion.


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## vagabondcyclist (Apr 2, 2011)

Grease and a torque wrench (and knowing how to use one) are your friends.


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## tlg (May 11, 2011)

usedtorace said:


> I still think the design sucks.


Sorry if I find no basis for your opinion. Given that you've admitted you don't really know what your doing. That possibly the shop doesn't know what they're doing. And that you have no idea how to inspect them for damage. 

Millions of people have rode millions of miles with that crank. Yet we don't ever hear of them just falling off. Go figure.
From an engineering perspective, a splined shaft with double clamping bolts and a safety locking tab is a fine design.


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## usedtorace (Mar 13, 2015)

tlg said:


> Sorry if I find no basis for your opinion. Given that you've admitted you don't really know what your doing. That possibly the shop doesn't know what they're doing. And that you have no idea how to inspect them for damage.
> 
> Millions of people have rode millions of miles with that crank. Yet we don't ever hear of them just falling off. Go figure.
> From an engineering perspective, a splined shaft with double clamping bolts and a safety locking tab is a fine design.


You are so right! I suck and the design is awesome.  

Just looking for some advice here as I've had some great advice before. I have ridden tens of thousands of miles on other cranks that I've put on myself and never once had a problem. Going all the way back to 1985. I think I just need to learn how to put them on correctly. Having my LBS check it tomorrow.


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## jetdog9 (Jul 12, 2007)

How about a picture of how it looks now just to see if anybody notices something you're overlooking? Definitely a weird one.


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## goodboyr (Apr 19, 2006)

The only instance of this type failure I've seen was someone in our club who installed a set himself. Admitted that he didn't use a torque wrench and didn't tighten the bolts alternately to ensure even torque. 

Sent from my SM-G900W8 using Tapatalk


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## usedtorace (Mar 13, 2015)

goodboyr said:


> The only instance of this type failure I've seen was someone in our club who installed a set himself. Admitted that he didn't use a torque wrench and didn't tighten the bolts alternately to ensure even torque.
> 
> Sent from my SM-G900W8 using Tapatalk


I had my LBS check it with a torque wrench but assembled it initially myself. That said, I do all my wrenching myself and this crank design is totally new to me. I *think* I assembled it correctly according to instructions and did have the torque wrench check. The more I read about this, the more it becomes apparent that the LBS maybe didn't get the torque right.


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## sasquatch16 (Feb 7, 2013)

bigjohnla said:


> Did you put loctite on the bolt threads when you installed the crank? I agree, there is nothing wrong with Shimano cranks. They are awesome and a great value.


Is loctite recommended? I have only torqued, taken a ride and retorqued


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## Srode (Aug 19, 2012)

usedtorace said:


> That's a great suggestion.


Not it's not


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## Roland44 (Mar 21, 2013)

usedtorace said:


> The more I read about this, the more it becomes apparent that the LBS maybe didn't get the torque right.


Yeah seems like it but it's hard to tell without a picture..


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## cxwrench (Nov 9, 2004)

tlg said:


> The cap does nothing to hold the arm on. It's just for adjustment. You could remove it after the crank is tightened.
> 
> 
> Absolutely positively nothing wrong with the design. $180 is a good price for a good crank.


Wrong...the cap needs to stay on. The cap pulls the arm into position and adjusts preload on the bottom bracket bearings. When the pinch bolts are tightened the crank axle is tightened around the cap. The cap and the pinch bolts back each other up and you absolutely have to leave the cap in place or the arm will work it's way off the axle. Ask me how I know...



bigjohnla said:


> Did you put loctite on the bolt threads when you installed the crank? I agree, there is nothing wrong with Shimano cranks. They are awesome and a great value.


Do NOT use loctite...grease the pinch bolts and torque them properly and everything will be fine.


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## goodboyr (Apr 19, 2006)

Weird that the cap plays a role since it's just a piece of plastic. Presumably the plate with the pin also plays an important role to keep things in place. 

Sent from my SM-G900W8 using Tapatalk


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## cxwrench (Nov 9, 2004)

tlg said:


> The cap does nothing to hold the arm on. It's just for adjustment. You could remove it after the crank is tightened.
> 
> No
> 
> ...





bigjohnla said:


> Did you put loctite on the bolt threads when you installed the crank? I agree, there is nothing wrong with Shimano cranks. They are awesome and a great value.





goodboyr said:


> Weird that the cap plays a role since it's just a piece of plastic. Presumably the plate with the pin also plays an important role to keep things in place.
> 
> Sent from my SM-G900W8 using Tapatalk


They've been aluminum at various times. Doesn't really matter what the material is, the axle is compressed around it when the pinch bolts are tightened and that keeps it from backing out. If it can't back out the crank arm can't fall off.


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## loxx0050 (Jul 26, 2013)

goodboyr said:


> Weird that the cap plays a role since it's just a piece of plastic. Presumably the plate with the pin also plays an important role to keep things in place.
> 
> Sent from my SM-G900W8 using Tapatalk


Previous version Shimano cranks had metal preload bolts while the latest gen are now plastic. I also don't think the plastic version would do very much holding it together should the pinch bolts come loose. But, it is recommended as a dust cap after you finish preload. It (preload bolt) shouldn't come loose if you tightened the pinch bolts correctly.


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## craiger_ny (Jun 24, 2014)

A bicycle shop has no way of verifying that the proper run down torque was applied to a fastened joint using the proper method (i.e. run down order). My point being that just because your shop's "check-up" didn't reveal any issues that doesn't mean that some were not lingering.


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## Blue CheeseHead (Jul 14, 2008)

In my experience Shimano crank arms are the least likely to fall off. If properly torqued and the plate with the pin is properly placed it is near impossible for them to work their way off. I am not sure what you did, but it is most certainly installer error here.


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## wim (Feb 28, 2005)

Blue CheeseHead said:


> In my experience Shimano crank arms are the least likely to fall off. If properly torqued and the plate with the pin is properly placed it is near impossible for them to work their way off. I am not sure what you did, but it is most certainly installer error here.


This ^.

On the stopper plate: Even with the pinch bolts loose, the stopper plate will keep the crank from falling off if the plate was snapped in place correctly at the initial installation of the crank. Early Hollowtech II cranks didn't have the plate. Shimano designed and introduced it in response to incidents of cranks coming off the spindle when the pinch bolts came loose.


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## Migen21 (Oct 28, 2014)

It seems strange that it would just fall off without you noticing it was loose beforehand.

Technically, there are three things that should help prevent the thing from falling off. 


In order of installation:

The pre-load cap
The pinch bolts (should be tightened and torqued by alternating back and forth).
The lock plate (stopper pin?) which is that thin piece of plastic in the slot on the crank arm. That things job is to prevent the crank from falling off if the other two things fail.

Let's assume that the pinch bolts came loose, AND the pre-load cap fell off completely (both *HIGHLY* unlikely occurences if they are installed correctly). The lock plate should keep the crank on the axle long enough for you to notice the thing is loose.

It's nigh on incomprehensible to me that this three safety system could just fail catastrophically in an instant, even if any one of the 'systems' failed.. the other two should have held it on, at least until you felt it wobbling (it would wobble considerably as it worked itself off the axle).

Very strange.


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## wim (Feb 28, 2005)

Migen21 said:


> The lock plate (stopper pin?) which is that thin piece of plastic in the slot on the crank arm.


You put a question mark, so you're going to get an answer. Shimano's term for this part is "stopper plate." The pin is part of the plate.


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## Cooper1960 (Oct 14, 2010)

I can't imagine a crank arm becoming loose enough to work its way off and it wasn't noticed! The design is good and installation isn't complicated.

The OP said something about the shop said the plastic cap wasn't necessary, so here's what I'm thinking. I bet when the OP installed the crank arm he didn't slide it all the way on, he tried to position it out wider where his big guy legs were spread and more comfortable, possible the outer tension bolt wasn't even on the crank. When he took it to the shop for inspection and they saw the stopper plate wasn't installed he probably said "I know, but I needed the arms out more because I'm a big guy", shop guy says "uh, OK, I guess you can use them like that". (shop guy is probably a school kid working on summer break, too afraid to tell this big guy adult he's a dufuss)

Honestly thats the only scenario I can imagine where it would just pop off, it was never all the way on to begin with.


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## rm -rf (Feb 27, 2006)

I use grease, not locktite. And torque the two pinch bolts.

I removed the "stopper plate". I assume it's final insurance for a bad installation. My Ultegra crank had a *plastic plate* with a *tiny metal pin* to fit into the slot in the threaded axle. Not much protection!

The cap is for adjusting the bearings before tightening the pinch bolts. It's not going to hold the crank on the axle if the bolts are loose. It's kind of locked in when the two bolts are tight, anyway.

~~~~~~~~~
OP, did you have clicking or creaking noises while pedaling before the arm fell off? That's often from a loose crank arm, due to loose bolts.

This "two pinch bolt" arm is the easiest for an amateur mechanic to install correctly. I like it.


~~~~~~~~~



Cooper1960 said:


> I can't imagine a crank arm becoming loose enough to work its way off and it wasn't noticed! The design is good and installation isn't complicated.
> 
> The OP said something about the shop said the plastic cap wasn't necessary, so here's what I'm thinking. I bet when the OP installed the crank arm he didn't slide it all the way on, he tried to *position it out wider* where his big guy legs were spread and more comfortable, possible the outer tension bolt wasn't even on the crank. When he took it to the shop for inspection and they saw the stopper plate wasn't installed he probably said "I know, but I needed the arms out more because I'm a big guy", shop guy says "uh, OK, I guess you can use them like that". (shop guy is probably a school kid working on summer break, too afraid to tell this big guy adult he's a dufuss)
> 
> Honestly thats the only scenario I can imagine where it would just pop off, it was never all the way on to begin with.


I don't think so. If the arm was installed wide like that, the whole axle would be loose, and able to slide left and right.

Bolts can work loose if they aren't tight enough to begin with.


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## wim (Feb 28, 2005)

rm -rf said:


> I removed the "stopper plate". I assume it's final insurance for a bad installation. My Ultegra crank had a *plastic plate* with a *tiny metal pin* to fit into the slot in the threaded axle. Not much protection!


The plate is insurance in case the pinch bolts come loose. That can happen even if the bolts were tightened according to the instructions. I'd put the plate back.

As to the plastic: there's no need for anything stronger. The plate is reinforced on both sides by the crank material. In addition, plastic can't corrode as a metal stopper plate probably would over time. Clever design for a fix, actually.


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## cxwrench (Nov 9, 2004)

Cooper1960 said:


> I can't imagine a crank arm becoming loose enough to work its way off and it wasn't noticed! The design is good and installation isn't complicated.
> 
> The OP said something about the shop said the plastic cap wasn't necessary, so here's what I'm thinking. I bet when the OP installed the crank arm he didn't slide it all the way on, he tried to position it out wider where his big guy legs were spread and more comfortable, possible the outer tension bolt wasn't even on the crank. When he took it to the shop for inspection and they saw the stopper plate wasn't installed he probably said "I know, but I needed the arms out more because I'm a big guy", shop guy says "uh, OK, I guess you can use them like that". (shop guy is probably a school kid working on summer break, too afraid to tell this big guy adult he's a dufuss)
> 
> Honestly thats the only scenario I can imagine where it would just pop off, it was never all the way on to begin with.


You've never actually worked on one of these cranks, right?


Sent from my iPhone using Tapatalk


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## Cooper1960 (Oct 14, 2010)

cxwrench said:


> You've never actually worked on one of these cranks, right?
> 
> Sent from my iPhone using Tapatalk


Obviously not. 20160814_130958.jpg

My Ultegra has no pre load or stopper plate, or if it did I sure didn't know about when I installed it. My reply was based solely on my imaginary "what if". Since this is the internet I saw no reason to let my opinion be trumped by my lack of experience.
(joking....my bad for a WAG)

mea culpa!

Edit; And my picture didn't post, obviously I'm not qualified at anything.


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## RoadCube (Nov 22, 2006)

CXWrench, please excuse my ignorance but:
Is the load on the cap similar to pinch bolts and cap-bearing adjustment on 
threadless headset?
RC


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## cxwrench (Nov 9, 2004)

RoadCube said:


> CXWrench, please excuse my ignorance but:
> Is the load on the cap similar to pinch bolts and cap-bearing adjustment on
> threadless headset?
> RC


No, it's different. The cap threads into the crank axle that is permanently pressed into the drive side arm. The non drive side arm slides onto the axle and the cap is threaded on, pushing the arm into proper position to eliminate any side to side play of the axle. The pin on the stopper plate goes into the hole on the axle when the plate is pushed down and the pinch bolts are then tightened. As I posted previously this does 2 things: it clamps the arm onto the axle and also tightens the axle around the cap preventing it from backing out.

eta: I guess the way that you 'adjust' and fact that both crank arm and stem have pinch bolts make it mostly similar, but the stem/steerer tube see very different loads. You can remove a top cap from a threadless system and everything will be fine. The difference is that once the pinch bolts are tightened on the Shimano crank you pretty much cannot back out the cap. It's held tightly by the axle.


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## Migen21 (Oct 28, 2014)

rm -rf said:


> I removed the "stopper plate". I assume it's final insurance for a bad installation. My Ultegra crank had a *plastic plate* with a *tiny metal pin* to fit into the slot in the threaded axle. Not much protection!


Inquiriing minds want to know.

Did you remove this for weight savings? Or was it somehow offensive that it was on there?


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## Blue CheeseHead (Jul 14, 2008)

The real key to proper installation of a left Shimano crank arm is to get equal torque on the two pinching bolts. One MUST go back and forth a few times to check the torque. If one torques one and then torques the second one just a little tighter than the first, then the second bolt removes the torque from the first. I use a torque wrench and start with a low torque and work my way up to final torque in several steps similar to what one does to properly install a cylinder head on an engine.

rm-rf, that little metal pin provides plenty of protection to hold the crank arm long enough to notice it is loose. Granted, I have never seen a Shimano come loose the way I have seen SRAM or FSA single bolt setups do...BTW they have NO protection whatsoever.


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## TmB123 (Feb 8, 2013)

That little stopper plate and pin holds the cranks on plenty good. The first time I ever tried to pull my NDS crank off I loosened both bolts and couldn't get the crank off for love nor money, couldn't work it out, eventually got it off with brute force and levering the crank off virtually ripping the pin out of the plastic. No way that sucker is just going to fall off.

So I'm not sure if the person who did this instal used the stopper plate...


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## goodboyr (Apr 19, 2006)

4 pages and we all seem to agree if it's installed as per the instructions it won't fail..........👍

Sent from my SM-G900W8 using Tapatalk


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## cxwrench (Nov 9, 2004)

goodboyr said:


> 4 pages and we all seem to agree if it's installed as per the instructions it won't fail..........
> 
> Sent from my SM-G900W8 using Tapatalk


Funny how that works _nearly _ every time


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## Lombard (May 8, 2014)

goodboyr said:


> The only instance of this type failure I've seen was someone in our club who installed a set himself. Admitted that he didn't use a torque wrench and *didn't tighten the bolts alternately to ensure even torque*.
> 
> Sent from my SM-G900W8 using Tapatalk


Note the part in bold print. This is critical!

Even if you followed directions to the letter - tightened bolts alternatively to 12-14Nm, you need to go back after 200-300 miles and re-torque these bolts. Also, did you put grease on the bolts? If not, then torquing the bolts down to specified torque did not get them as tight as they need to be.

Re: Your "massive wattage": For this to be enough to loosen these bolts, you probably would have sheared off your crank arm first.


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## Lombard (May 8, 2014)

cxwrench said:


> No, it's different. The cap threads into the crank axle that is permanently pressed into the drive side arm. The non drive side arm slides onto the axle and the cap is threaded on, pushing the arm into proper position to eliminate any side to side play of the axle. The pin on the stopper plate goes into the hole on the axle when the plate is pushed down and the pinch bolts are then tightened. As I posted previously this does 2 things: it clamps the arm onto the axle and also tightens the axle around the cap preventing it from backing out.


This.

The cap is torqued to only (if I remember correctly) 1.5Nm or something unmeasurable by any torque wrench. You also need a special tool to tighten this.

The pinch bolts torque to 12-14Nm alternatively in very small increments. Use grease on the threads and re-torque after the first 200-300 miles.

No loctite!


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## Migen21 (Oct 28, 2014)

Edited for accuracy:


Lombard said:


> The cap is torqued to only (if I remember correctly) 1.5Nm or something unmeasurable by any torque wrench. You also need a special tool to tighten this.


There is no single specific torque value per-se... The purpose of that 'cap' is to apply proper load on the BB bearings. Different bearings require different load.

To know how much it is, you need to know what type of bottom bracket and bearings you have. Per the "Enduro Bearings" FAQ, the XD-15 BB w/Angular Contact bearings requires ~5-7Nm of torque.. Radial bearings will require much less (barely finger tight). 

Here is the exact quote:


Enduro Bearings FAQ said:


> *How do I properly torque my XD-15 bottom bracket?*
> 
> 
> The most important part of setting up an XD-15 bottom bracket with Angular Contact (A/C) bearings is getting the preload set correctly. Briefly, these bearings need to be preloaded 40-60 inch lbs. or 5-7 Nm. This is about 5x the torque setting of a standard radial bearing.


Other types of BB's with angular contact bearings will be less. 



Enduro Bearings FAQ said:


> *How do I properly torque Enduro Bearings Angular Contact bottom bracket or wheel bearings?
> 
> *Enduro Bearings Angular Contact (A/C) bearings require some preload, though not nearly as much as the the XD-15 A/C bearings. This is because they have a shallower A/C design. The bottom bracket torque numbers for A/C bearings should be 12-26 inch lbs, or 1.2 - 3 Nm. This is roughly twice the normal radial bearing torque numbers. Again, this can be achieved by the torque ring or torque nut on a Shimano or similar crank system, or with the light (0.4 mm) wave washer completely flattened after the cranks are torqued onto the spindle to manufacturer specifications. This service should only be performed by a qualified trained technician from a bicycle shop.


This is an example of one manufacturers procedures. 

The bottom line here is, know your equipment, and reference the manufacturers install procedures/specifications.


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## Lombard (May 8, 2014)

Migen21 said:


> Edited for accuracy:
> 
> 
> There is no single specific torque value per-se... The purpose of that 'cap' is to apply proper load on the BB bearings. Different bearings require different load.
> ...


The 1.5Nm torque spec in the Shimano directions assumes you are using the Hollowtech II BB that comes with the new Shimano crankset.


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## usedtorace (Mar 13, 2015)

Lombard said:


> Note the part in bold print. This is critical!
> 
> Even if you followed directions to the letter - tightened bolts alternatively to 12-14Nm, you need to go back after 200-300 miles and re-torque these bolts. Also, did you put grease on the bolts? If not, then torquing the bolts down to specified torque did not get them as tight as they need to be.
> 
> Re: Your "massive wattage": For this to be enough to loosen these bolts, you probably would have sheared off your crank arm first.


The massive wattage thing was a joke, people! 

I actually think the design is pretty good after talking to my local bike shop. We got it figured out. It was the pinch bolts loosening somehow . . . really flukey. The cranks are still good and I'm sold on their design after studying the set-up a little further this weekend. 

Thanks for the good advice--to those of you who weren't incredibly condescending and critical. No way I'll ever post here again with wrenching questions!


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## Lombard (May 8, 2014)

usedtorace said:


> The massive wattage thing was a joke, people!


I gathered that hence the grin icon on my previous remark.



usedtorace said:


> I actually think the design is pretty good after talking to my local bike shop. We got it figured out. It was the pinch bolts loosening somehow . . . really flukey.


Not fluky at all. If you buy a bike at any good shop, they will ask you to come in at around 200-300 miles for a free follow up. They will go around and re-tighten bolts.



usedtorace said:


> Thanks for the good advice--to those of you who weren't incredibly condescending and critical. No way I'll ever post here again with wrenching questions!


You're welcome. Don't let some posts discourage you from posting on message boards. The internet can be a harsh place. Even the condescending ones can be helpful. I always put on my Nomex underwear before posting in here.


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## tlg (May 11, 2011)

usedtorace said:


> Thanks for the good advice--to those of you who weren't incredibly condescending and critical. No way I'll ever post here again with wrenching questions!


People post wrenching questions every day and don't get that treatment. So what do you think makes you different? When you start off sounding and acting like a troll you tend to get treated as such. 




> I actually think the design is pretty good after talking to my local bike shop. We got it figured out. It was the pinch bolts loosening somehow . . . really flukey. The cranks are still good and I'm sold on their design after studying the set-up a little further this weekend.


So after everyone here (many with more experience than your shop) tell you the design is fine you argue. But now you think it's good... after studying it. 

Advice... next time... study first before making off the wall critical comments.


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## Lombard (May 8, 2014)

tlg said:


> People post wrenching questions every day and don't get that treatment. So what do you think makes you different? When you start off sounding and acting like a troll you tend to get treated as such.


Oh com'on, TLG! Couldn't you tell the "massive wattage" remark was tongue in cheek, not trolling?  

Usedtorace, don't be intimidated by the green poisoned face on TLG. When you get to know him well, he can be a really cuddly bunny. :wink5:


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## tlg (May 11, 2011)

Lombard said:


> Oh com'on, TLG! Couldn't you tell the "massive wattage" remark was tongue in cheek, not trolling?
> 
> Usedtorace, don't be intimidated by the green poisoned face on TLG. When you get to know him well, he can be a really cuddly bunny. :wink5:


Well... he wouldn't be the first troll to come in bragging about massive wattage. And sub 5:15 century... And being a former Cat. 3 racer. Smells fishy.
But I gave him the benefit of doubt that be was pulling a Trump and just being "sarcastic" after saying he was kidding about the wattage.

It was the insisting over and over that the design is crap (in light of everything else).


And cuddling costs extra.


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## JTO (Mar 18, 2013)

If you have an early model Ultegra crank, you may not have a stopper plate. Now you know why Shimano added it.

The stopper plate does two critical things: it ensures you properly mounted the crank arm onto the spindle (otherwise it won't close) and it provides a fail-safe if the crankarm bolts come loose. It does both of those things very well. _Some_ shops remove the stopper plate because it's a total b*tch to snap shut and remove for maintenance (like BB work). That immediately voids your warranty, so make sure it's in place if you're buying a bike. In fact, if a shop removes it, never buy anything from them.

I've ridden/raced on Shimano, SRAM, RaceFace, and FSA cranks. Properly maintained and torqued, none of them will just come off on you (though FSA cranks creak and loosen if you stare at them too hard). Loctite is fine to use as long as you use the removable type and let it dry on the threads before assembly. Not needed, but fine.


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## Lombard (May 8, 2014)

JTO said:


> _Some_ shops remove the stopper plate because it's a total b*tch to snap shut and remove for maintenance (like BB work).



Seriously? I have opened and closed these a number of times. If it doesn't snap shut, that is a red flag right there that the arm didn't push in far enough. It isn't strong enough to hold the arm in, but it is a good fail-safe that ensures you got the arm on far enough. Can you say Darwin Award? And opening it takes nothing more than small needle nose pliers.



JTO said:


> In fact, if a shop removes it, never buy anything from them.


Exactly.


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## cxwrench (Nov 9, 2004)

tlg said:


> The cap does nothing to hold the arm on. It's just for adjustment. You could remove it after the crank is tightened.
> 
> No
> 
> ...





bigjohnla said:


> Did you put loctite on the bolt threads when you installed the crank? I agree, there is nothing wrong with Shimano cranks. They are awesome and a great value.





JTO said:


> If you have an early model Ultegra crank, you may not have a stopper plate. Now you know why Shimano added it.
> 
> The stopper plate does two critical things: it ensures you properly mounted the crank arm onto the spindle (otherwise it won't close) and it provides a fail-safe if the crankarm bolts come loose. It does both of those things very well. _Some_ shops remove the stopper plate *because it's a total b*tch to snap shut and remove for maintenance (like BB work).* That immediately voids your warranty, so make sure it's in place if you're buying a bike. In fact, if a shop removes it, never buy anything from them.
> 
> ...


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## TmB123 (Feb 8, 2013)

I just take both bolts right out of the crank and flick the stopper out with a small screwdriver. Takes 5 seconds.


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