Hi there guys,

I'm pulling my hair out over this one.

So, i'm trying to pull the crank arms from this SystemSix (it's a friends) and never worked on this Hollowgram system before.

It appears these things have weird end caps are quite difficult to remove, and its like behind the end cap, there is another screw that spins free to the end cap.

I've got the removal tool to use once I can remove this silly end cap, but finding it really hard to even make the thing budge, am i missing something?

Using an allen key driver to attempt to remove this but also fear i may round off the inside of it.

Any help would be super appreciated if anyone knows much about these types of crank arms.

Welcome to Bike Forums.

Are you referring to the removal of the Crank Arm retaining Cap/bolt.
The one that fits a 10mm hex wrench and likely has the torque spec written on it ?

Barry

If it's like a Praxworks you leave the outer nut on and make sure it's tightened in. Then you slip the allen wrench through it into the inner nut and turn counter clockwise, forcing that nut against the outer nut and essentially driving/pulling the crank arm off the shaft. Then the rest just pulls through the bottom bracket and out the other side with a slight tap to free it.

Hey Barry,

Yes that’s the one, shows as 40nm to remove the cap and has two direction indicators, one for removing the inner bolt and one for the outer cap.

Needs a specific tool. (This may be the one you referred to, missed that)

Cannondale uses both pressfits and threaded bottom brackets. Hopefully his uses threaded.
Most cranksets employed by them utilize a self-extracting arrangement, either driveside or non-driveside.
My 8mm allen sits on the driveside. Turning it counterclockwise with the outer ring on will allow you to self-extract.
Sometimes these get torqued on at tremendous tightness, so you may need a large breaker bar.
I like socket keys to attach to a humongous ratchet handle.
It helps if you can get someone to hold the bike, while you hold the other crank arm firmly.

Ahh wait, so basically I shouldnt remove the outer ring then?

Would be cool if i could post a photo of this thing but the forum says i need more than 10 posts :-)

Another forum member posted a video. Check that out to see if it matches your configuration.
You can remove that outer ring until you break loose the allen bolt. Then re-install it to extract the arm.
These can be total buggers to remove. Stay patient and use good tools.
When putting things back together, apply a thin layer of grease to the allen bolt threads.
And torque to the proper settings, without overdoing it.

Ok, yes i checked the video and that outer ring is different to the one I can see.

This one looks thinner in thickness and as stated in post above, there is another ring behind the outer cap that also has a hex pattern, looks like an 8mm one and the outer one is a 10mm one.

I can stick a long allen key inside it and loosen up the 8mm one, it creates a very small gap between the outer ring and the inner piece.

Still can't move the outer ring, its like its frozen. Have sprayed some WD40 on it and will wait a bit to see if it helps release it.

Yes it's very VERY tight, seems impossible to remove

Okay, you do not need to remove the outer ring. It stays there to give the allen bolt something to push against.
Loosening the 8mm is a big step. Keep turning counterclockwise. It will press against that ring as you continue turning.

roadcrankr ,
Is there such a thing a Hollowgram self extracting crank arms ?
I'm a Shimano guy, but my buddy has Cannondale.

Barry

Correct. You shouldn't even try to. The external nut is usually fairly thin/shallow and threadlocked in place pretty well. Any attempts to remove it with a hex wrench will usually chew it up and ruin it. You are not supposed to remove it.

The inner 8mm is much deeper and should be removable with an ordinary hex.

All above comments and advice seem accurate. But the description of "very, VERY tight" is an understatement. I use a 18" breaker bar with a hex socket to break the torque during removal. But if you think that removal is hard, installation is even worse. I think the spec calls for 40nm which doesn't sound too bad but most torque wrenches aren't long enough to give you good leverage and every time I do this I swear something bad is going to give when the wrench finally clicks. IME if you don't torque the sucker down it'll make all sorts of noises. You can do this alone, but its easier with 2.

This is the picture of your crank?


https://www.bikeforums.net/g/album/30840372


I think it's a self extracting crank. You need to leave that cap on and then put a 10 mm hex key in it and turn it counter clockwise. The instructions are basically printed on it right there. Though they are talking about putting it on. And yes it might be sort'a hard if you have a short hex key. They sell longer ones.

Welcome to BF. If you need to post any more pic's before you get 10 posts, then just let us know in your post that you put them in the Gallery.

Yes. And I will add that I find them to be the easiest to work on because they don't require any special tools aside from the allen wrench that fits the inner bolt. Also, I use a rubber mallet tapping against the 'hex' wrench works better than using cheater bars for removal.