Cannondale SI crank + FSA/Sram bb30 crank arm bolt

Discuss light weight issues concerning road bikes & parts.
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alcatraz
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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Hi WWs

I have a sisl2 crank that works fine but the threads for pulling the arms are weak. I don't use them anymore.

I recently got a sram red bb30 crank to reduce the weight a bit and I noticed that the axle and bolt seems to fit either combination. Sram arm on sisl2 axle or cannondale arm on sram red axle.

It got me thinking to put (with some nice strong loctite compound) one of those sram red/fsa self extraction bolts on the sisl2 crank to "fix" it.

Do you have any experience with that?

/a
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fs0011__51699.1524375296.jpg

by Weenie


alcatraz
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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Does noone even care to speculate a bit?

I'd appreciate it.. :)

I guess I could simply try it but...

/a

dudemanppl
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Joined: Fri Feb 22, 2013 5:09 am

by dudemanppl

I think the only reason Cannondale doesn't spec this themselves is because of the 10g+ this would probably add per side. Plus they get to sell their stupid $50 dollar tool... Let me know how this works out because you theoretically only need one on the NDS.

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Dan Gerous
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Joined: Sun Aug 12, 2007 6:28 pm

by Dan Gerous

The SRAM self extraction bolt does fit in a Hollowgram SISL2 spindle, I just tried it after reading your post, but does not fit in the SISL2 (or SI or older SL) arms. Once installed, just the main bolt with the convex head sticks out of the arm, you can't install the outer part as it can't even reach the threads of the crankarm, it can barely touch the arm at all, even without the washer that goes under the bolt.

alcatraz
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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Cannondale/sram/fsa and more use the same spindle design.

The question is if the arms are similar enough on the opposite side to allow for swapping of bolts.

I've seen older SI cranks with self extracting bolts. I wonder if those are long enough to reach the threads when put on an sisl1/2 arm.

They do look like they were made by fsa for cannondale so perhaps they have shorter bolts too.
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canondale_cranks_315.jpg

alcatraz
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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Dan Gerous wrote:
Mon May 27, 2019 10:14 pm
The SRAM self extraction bolt does fit in a Hollowgram SISL2 spindle, I just tried it after reading your post, but does not fit in the SISL2 (or SI or older SL) arms. Once installed, just the main bolt with the convex head sticks out of the arm, you can't install the outer part as it can't even reach the threads of the crankarm, it can barely touch the arm at all, even without the washer that goes under the bolt.
Take a look at the bolt in my picture here. That seems very long. That must work.

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Dan Gerous
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by Dan Gerous

Ha yes, I remember those, indeed made by FSA, I had one at some point but it's long gone now so I can't try it but the Hollowgram are very different in the bolt area, different interface if I recall.

alcatraz
Posts: 2208
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Found this for s-works cranks.
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Screenshot_20190528-095148.jpg

by Weenie


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Dan Gerous
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Joined: Sun Aug 12, 2007 6:28 pm

by Dan Gerous

Just thought of something, isn't the... I'm not sure how to call it but, you thread the bolt clockwise but that other part you install after the bolt, isn't it reverse threaded? The thread in the Hollowgram arms is regular threaded so if all these self-extracting 'retainers' are reverse-threaded, they wouldn't work.

I still think there's just not enough depth for a self-extracting bolt in the Hollowgrams, the SRAM bolt I tried has it's head sized bigger than the arm's thread so the other part can't be used even if there was enough dept. That S-Worls look smaller in diameter though. I wouldn't mind to be proven wrong though! :thumbup:

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