Replacing FSA Gossamer crankset with Ultegra 6700

stringybob

Having successfully completed my first and only meaningful bit of bike maintenance (replacing cassette and chain) I found myself flushed with a new (and completely unfounded) confidence and have impulsively purchased a new Ultegra 6700 compact chainset to replace my current FSA Gossamer 46/36 (mainly for cosmetic reasons as the cranks are particularly worn and tatty looking).
Now having looked into it a bit further I am worried I am out of my depth. My 3-point plan is:
A) - remove the existing crankset and fix the new one, re-using the existing bottom bracket (dont know what type the existing BB is and not sure what to look for to identify it). Everything works out fine and I sit back with a glass of red and admire my handywork
- the existing BB is not compatible so purchase and install an Ultegra 6700 BB. Crack open the red.
C) - A and B both do not work so put all the bits in a carrier bag and take to LBS

Any input / advice would be greatly appreciated

apreading

Is the Gossamer BB a Mega-Exo? If so then I believe this is compatible with Shimano Hollowtech ii, which I believe means the ultegra chainset should fit. I could be wrong though.

If the Gossamer is BB30 or PF30 then you could be in trouble - the frame may not even fit Hollowtech, although a quick search suggests there may be an adapter to make it fit...

viewtopic.php?p=16762638

stringybob

Thanks apreading. Just did a quick Google of Mega-Exo and I would say that looks just like the one I have

wotnoshoeseh

If Mega Exo then, and apreading is correct, then sounds like you're good to go.

If it is BB30 though there are adaptors to fit. My Felt F4 is BB30 but came fitted with an Ultegra crankset, and the appropriate adaptors.

apreading

Looking at your posts, it seems you have a Jake the Snake? Googling the interweb suggests they were Mega-Exo in 2010, BB30 from 2011 onwards...

http://www.bikepedia.com/quickbike/Bike ... +The+Snake
http://2011.konaworld.com/bike.cfm?cont ... _the_snake
http://2k12.konaworld.com/cx.cfm?content=jake_the_snake
http://www.konaworld.com/jake_the_snake.cfm

stringybob

Just had a good look at the existing BB and it is definitely the Mega-Exo. Thanks again

dgunthor

when/if you need to replace the BB, any shimano hollowtech II BB will do - doesn't have to be an ultegra one - the MTB ones fit too (just don't use the supplied spacers is all)

Mac9

Interesting thread for me this - I've been looking at changing from a compact to a standard on my GT GTR Series 1, which has a BB30. I was considering buying an Ultegra 6700 crankset but wasn't sure about the compatibility issues as I'm a complete novice in this department!

Do the adapters make any difference in terms of quality?

Would I be better off getting an FSA crankset that would be a straight swap?

stringybob

Just one more stupid question. I've fixed the crankset but it didn't come with a crank arm end bolt so I've ordered one from Chain Reaction. Can I use the bike in the meantime as it all seems pretty solid - what exactly does it do?

dgunthor

end bolt is used to tighten the cranks to avoid play in the bottom bracket - the 2 bolts in the LH crank hold it all on.

you could ride without it just check there's no play (i'd be suprised if there was no play)

Giraffoto

You can get away without the preload screw if you squeeze the cranks together very gently with a sash cramp (or similar). Careful how you go though.