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-   -   BB30 crankset installation issue (https://www.bikeforums.net/bicycle-mechanics/1102470-bb30-crankset-installation-issue.html)

williamset 03-26-17 08:03 AM

BB30 crankset installation issue
 
I'm trying to replace the stock FSA Gossamer BB30 crankset on my Cannondale CAAD10 with a FSA Hollow Carbon Crank BB30 (It's essentially an SL-K). The torque spec is 36 NM for the new crank and I'm using a calibrated torque wrench to install the new crank.

As soon as I reach roughly 28 NM of torque on the new crank it stops spinning freely. It still turns smoothly, but there is a significantly more resistance than would be expected. The resistance gets worse the more torque I apply.

Any idea what could be wrong? I have installed bearing covers on both sides. I tried a space and the wave spring washer on the non drive side. I've also tried no spacer but the spring washer on the non drive side. Both yield the same result...Crank is clean and lightly greased on the machined portion of the spindle.

Please help! It's a nice day and I want to get out!

Thanks!

williamset 04-13-17 06:23 PM

Anyone?

evan326 04-13-17 07:00 PM

Pictures help a lot.
How compressed is the wave washer? How many shims do you have?

Dan Burkhart 04-13-17 08:27 PM

Are you sure the washers are the right way around? Most BB30 cranks I've encountered have washers with a raised ridge which must face inward to compress against the inner race of the bearing. Can't remember right now if FSA cranks have that, but just dealt with a Rotor crank set that had that issue. Someone had installed the washers wrong and flipping them solved it.

trailflow1 04-13-17 09:38 PM


I'm trying to replace the stock FSA Gossamer BB30 crankset on my Cannondale CAAD10 with a FSA Hollow Carbon Crank BB30 (It's essentially an SL-K)
What does this mean ? Where did you source the crank from ? Which exact model is it ? it either is or it isnt an SL-K crank.

Does the FSA Hollow Carbon Crank have the exact same spindle length as the Gossamer crank ?

Have you checked the bearing covers are not the wrong way round. Back to front ?

Have you tried removing all the spacers and the wavy washer ? Have you experimented at all with removing 1 or both the bearings covers and using a plastic washer in their place instead ?

Are the BB30 bearings fully seated and are they against the circlips inside the shell ?

Is the carbon BB30 crank spindle definitely not twisted/bent ? Is it new or used ?

williamset 04-15-17 07:53 PM

Thank you all for the responses. I have since regreased but did not notice much of a difference. I've ridden the bike in this condition about 70 miles. It seems to function and the notchiness isn't noticeable when pedaling, but it is definitely noticeable when turning the crank by hand. The cranks on my other bikes spin much more freely and are smooth as silk. If I turn the crank on the BB30 bike really slowly by hand, I can feel the notchiness as the spindle turns in the bearings. I can also feel the notchiness if I turn the bearings by hand when the crankset is removed.

1) The crankset is labeled "Hollow Carbon". I believe it came off a Specialized Diverge and is not labeled with the traditional SLK logo's due to the fact it was OEM for the Specialized. It is in like new condition. The model off the label is CK-OS81. Here's a link to a photo (not my bike): https://www.picclickimg.com/00/s/MTA...on-Bb30-_1.jpg

2) The cover washers over the bearings are installed with the flat surface facing outward and the raised surface inward against the bearing.

3) There is 1 spacer on the non-drive side. It is between the crank arm and the spring washer. There are no spacers on the drive side.

4) The spring washer appears to be fully compressed. It is clearly not fully compressed until the very last turn of the torque wrench.

5) Bearings are definitely fully seated. Note, I did not remove the bearings or the backing clips. I have however examined their installation to confirm it is correct.

6) The crank spindle is not bent.


Any ideas? Am I worried about nothing?

fastk9dad 04-15-17 08:08 PM

Did the crank you pulled off spin freely?

My BB30 cranks, when torqued to spec, only make it one or two revolutions around before they stop if trying to spin by hand with no chain on. Much different than my cranks with outboard bearings which can spin for a while.

trailflow1 04-15-17 08:31 PM

If you can feel any notchiness. One or both the bearings could have damage and will need replacing. That could be contributing the extra resistance when you tighten the crank. More pressure is put on the damaged bearing(s) causing it to bind up.

or try removing the 1 spacer and wavy washer completely. Nothing bad is going to happen. It will give you a better idea if they are needed or not. If you remove them, and find there is side-to-side play of the crank. But the bearings still feel notchy. That says there is a problem with the bearings.

If instead, the crank spins freely and smoothly. That suggests the wavy washer and/or spacer are causing it to tighten up.

AngelPedaller 05-08-21 12:07 AM


Originally Posted by williamset (Post 19514012)
4) The spring washer appears to be fully compressed. It is clearly not fully compressed until the very last turn of the torque wrench.

5) Bearings are definitely fully seated. Note, I did not remove the bearings or the backing clips. I have however examined their installation to confirm it is correct.

6) The crank spindle is not bent.


Any ideas? Am I worried about nothing?

4) The spring washer appears to be fully compressed. It is clearly not fully compressed until the very last turn of the torque wrench.
It shouldn't and this is why you apply excessive force to the bearing blocking proper rotation. Remove one washer from NDS so that the torque is applied only between crank arm and spindle. Not against bearings. This is how the system is designed. The wave washer has enough power to stop lateral movement of crank. Check below photo showing that you should be able to see a bit of the spindle after tightening 20+Nm
https://cimg2.ibsrv.net/gimg/bikefor...93ce896723.jpg

smashndash 05-08-21 01:12 AM

Right. This sounds like a classic case of excessive preload. The issue is not the amount of torque you're putting into the crank bolt. That is designed to hit a hard stop, thus making the width of the crank fixed. The issue is that either your BB shell is slightly too wide for your cranks or there are too many preload washers.

Also: every bearing will feel "notchy" if excessively preloaded. This is called binding.

AngelPedaller 05-08-21 06:49 AM


Originally Posted by trailflow1 (Post 19514088)
If you can feel any notchiness. One or both the bearings could have damage and will need replacing. That could be contributing the extra resistance when you tighten the crank. More pressure is put on the damaged bearing(s) causing it to bind up.

or try removing the 1 spacer and wavy washer completely. Nothing bad is going to happen. It will give you a better idea if they are needed or not. If you remove them, and find there is side-to-side play of the crank. But the bearings still feel notchy. That says there is a problem with the bearings.

If instead, the crank spins freely and smoothly. That suggests the wavy washer and/or spacer are causing it to tighten up.

Wave washer should stay as it is the only thing stopping lateral movement of spindle. If you remove it, you need to find exact number of washers to compensate the fixed length of the spindle/crank setup.

BB30 spindles and cranks are fixed length. When they are tightened (at the superhuman torque of 40Nm - not yet achieved by mortals) it is final and you have to fill the gaps between both sides.
For BB30A Cannondale One crank for example with 109L spindle you have
109mm
- 10mm star shaped crank sockets NDS side
- 16mm star shaped crank sockets DS side
- 2.6mm DS washer
- 73mm of BB30A shell
- 2.5mm NDS washer
--------------------------------------------------------------
4.9mm gap from the NDS side that needs to be filled with 1 up to 3 0.5mm plastic washers and the wave washer.
This as per Cannondale's designs and it works.

Shimano has variable length by tightening the preload screw on the NDS and with a small hack (reversing the knotch clip of the NDS arm) you can play around for old school frames.


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