I tried to remove the chainrings from a chainset with it still installed on the bike, but failed to do so, so I just wanted to ask if it’s possible!

It’s a road triple FSA Gossamer with external BB cups, 130mm BCD, and with 52/39/30 chainrings. The outer ring obviously came off okay, but I couldn’t get the inner past the spider tabs even though I tried a few different angles etc.

I just want to clean them this time, so it won’t be an issue until I need to replace them, but I’d probably struggle to remove the crank arms or whatever might need to be done.

Depends on the chainset – some are removable without removing the chainset, some not.

Loosen all the bolts first, then take the crank off the bike. IIRC 5 bolt middle rings can be a PITA to get off with the crank in situ.

Very unlikely you will be able to get the inner ring off without pulling the cranks.

Inner no chance, middle possibly, depending on crank.

Thanks. I’ll put it back together for now! I may try to find out how to do it, but I suspect removing the cranks might exceed my mechanical capabilities!

Don’t think you’ll ever need to replace the inner on a Gossamer – it’s steel isn’t it ?

So I don’t think you’ll ever need to remove the cranks until the BB bearings fail.

What axle type is yours anyway ? They came in square taper, ISIS and most recently GXP (external bearings). They’re all fairly easy to service – only the square taper version requires a crank puller tool I think…

Mine has external bearings (MegaExo?)

The right hand looks hollow where it goes through the BB shell. I was thinking it might be possible to remove the left hand crank then simply slide the right hand one out. However, I’m not sure if it’ll be that simple, or what the re-assembly procedure would be. It would be handy if I could do it – at some point I may wish to change the BB.

I wondered about the chainrings, so I tested them with a magnet last night, and they’re all aluminium. The chainring bolts are steel, though!

Yes, it is that simple, you only need a single allen key – just remove the LHS crank arm and the rest will slide out. You just need a soft mallet, or block of wood and hammer to tap the axle into the BB shell, and all the way through until the drive-side crank and fixed axle slides out (they always remain as one piece). Assembly is just the reverse. The bearings stay in place, no need to touch them.

The type of LHS crank determines which allen key you need. Check the link to the following Park Tools mechanical guide, it lists MegaExo somewhere down the page – ignore all the stuff about bearing removal, you’re only interested in the section on crank servicing:

http://www.parktool.com/blog/repair-help/external-bearing-crank-systems-hollowtech-ii-megaexo-giga-x-pipe-x-type-campagnolo-ultra-torque

Thanks! It looks quite simple. I’ve got a Park Blue Book, but it must be the original edition, as it covers this in less detail. I’m tempted to buy some BB ceramic bearings too.