Sunday, 6 July 2014

Removing a SRAM BB30 MTB crank from a Cannondale

Well, this is going to be straight forward I assumed to myself. But no, an hour of effort and two large steel pipes for leverage later; I accepted a draw with my BB30 cranks.

How to remove the drive side crank

Firstly, don't try and remove the non-drive side crank. That doesn't come off and, yes whilst you can undo the 10mm hex bolt, you shouldn't need to.
Don't remove the non-drive
side crank bolt

  1. Go get yourself a long 10mm hex wrench (I use a Park Tools HT-10 and a Park Tools PH-10)
  2. Stick the 10mm hex wrench in the drive side crank and turn it in the opposite direction of the arrow on the bolt (anti-clockwise / to the left)
    • Use the crank as something to push or pull against
  3. Now this is where the bolt should come loose and when the self-extracting bolt is fully unscrewed the crank should come off
    • However, the fitting on my Cannondale Trigger was so tight, I ended up having to use two large steel tubes to push the cranks and 10mm hex wrench together (see pic below)
    • I heard two MASSIVE pings when I used the steel tubes and I presume that was just the threadlock giving way.
    • I did manage to scratch my cranks, but that's a small price to pay to know that they will now come off with a decent sized 10mm hex key on the trail side if needed
Hey presto, the crank should be off. Give it a good clean up and put some decent grease on the self-extracting bolt threads.

Those two white poles were needed to remove
the drive side crank!

Now to remove the non-drive side crank

In the first lines of this post I said that I accepted a draw because, for the life of me and all my tools, I couldn't get the non-drive side crank to come out.

The BB30 bottom bracket system is really tight. The bearings and the frame have to be perfect to get the right alignment between everything so that it all works smoothly. In my case, either I couldn't get the right alignment or something isn't rightly aligned in the first place.

What should happen, is with the drive side crank removed and the bearing preload adjuster unwound, a soft tap from a mallet will un-seat the non-drive side crank and allow it to be taken out.

What actually happened is that the crank got stuck half way and no amount of tapping with the mallet, silicon spray (to lubricate) or wiggling (the crank spindle, not me) could get the crank to come out.

This long handled Park Tools HT-10 wasn't enough
to remove the cranks
I settled with cleaning the crank spindle and bearings and put everything back together again.

My guess is that one of the bearings has deformed slightly and it's causing the spindle to catch.

Next time when I do need to remove the cranks, I'll spend some more time playing to get it to come out, otherwise I'll smash it out and simply replace the BB30 bearings with newer ones.

Putting it all back together again

Putting it back together, I doused everything in grease (I use Exus E-G01 grease) and then wiped any excess off. The trick is to ensure that everything inside the cranks (bearings, spindle, threads etc.) are completely covered with a 1-2mm covering of the stuff. Better to be safe than sorry. Also helps reduce rusting too. Any more and you may be impacting the ability for the cranks to turn! The second trick is to make sure that from the outside you can't see any grease. Grease on the outside of the cranks or by the bearings will just become a magnet for crap. Wipe it up with a bit of kitchen cloth.

Anyway, to put the cranks back on, make sure the bearing preload adjuster is wound out (and greased) and then slide the non-drive crank in first. You may need to tap it gently with a mallet to get it all the way through and flush with the bearing. Then add the spindle spacer to the drive side, put the chain inside between the frame and the crank and then finally add the drive side crank to the spindle.

Tighten the drive side crank self extracting bolt (that's had its threads greased) with a 10mm hex key.

Set the bearing preload as needed and wipe up and final grease. How many times did I say the word 'Grease'!

And it's done.

Comparison to Shimano and Hollowtech

Either it's SRAM or it's the Cannondale BB30 spec, but this was a job that should have taken 15 minutes to disassemble, clean and re-assemble my cranks. It certainly takes that long for my Shimano cranks and my other Hollowtech bottom bracket and crank combos.

Hopefully with the cranks now un-done, it will be easier next time, but the fact I was unable to easily remove the non-drive side crank was a disappointment and showed that something was wrong.

If in the future I need to replace my cranks on my Cannondale Trigger, I may just choose to use Shimano and get a BB30 to Hollowtech reducer.

8mm SRAM cranks

Lastly, if you find that your SRAM cranks have an 8mm hex key, then this guide isn't for you. For those SRAM cranks you need to insert your 8mm key in the non-drive side and undo the self-extracting bolt anti-clockwise.