Swapping groupsets - BB Questions

trickytree1984

Hi
I recently bought a new Bianchi Sempre pro 105. I have an old Specialized Allez which has Sora. I wanted to upgrade the group on the Spec to 105 5800 but instead decided on Ultegra 6800. The plan is to put that on my best bike (the Bianchi) and move the 105 to the Winter bike (Specialized). Now I already know that I can't move the front mech as it is band on one the Bianchi and braze on on the Specialized. What I do want is to move the chainset.

The Bianchi is bb30 bottom bracket and I want the Shimano 6800 crank on that. No problem, I think you can buy shims for that.

The crank to go on the Specialized is an FSA grossamer (bb30) and needs to go into a standard English threaded (68mm I think). Is that possible in any way?

Many thanks in advance.

nicklouse

Nope. You will need a 24mm axled crankset.

But just keep the BB30 set up in the BB 30 frame.

trickytree1984

nicklouse wrote:

Nope. You will need a 24mm axled crankset.

But just keep the BB30 set up in the BB 30 frame.

I suppose i will have to, it just seemed a waste putting the brand new 6800 crank on my old winter bike which will be part 105 5800. I might sell the 6800 crank then and just buy a 105 crank for the old bike, leaving the FSA crank on the new bike.

I though i read somewhere that this could be done though?

schlepcycling

Is this what you're after? http://www.velotechservices.co.uk/shop/vclose2.asp?prd=76574&cat=7416002009 it allows you to use a 30mm spindle in a 68mm threaded BB shell.

nicklouse

I think that only works with Rotors own crank that had a wider spacing.

BB30 is 68mm wide. Bering inside that measurement. Those cups will screw into a 68mm shell making the width about 74mm ( I forget the exact measurement, might be 75mm) which means that you can not use a BB30 crank.

Yes those cups will allow a 30mm axle but not a BB30 crankset to be used.

trickytree1984

nicklouse wrote:

I think that only works with Rotors own crank that had a wider spacing.

BB30 is 68mm wide. Bering inside that measurement. Those cups will screw into a 68mm shell making the width about 74mm ( I forget the exact measurement, might be 75mm) which means that you can not use a BB30 crank.

Yes those cups will allow a 30mm axle but not a BB30 crankset to be used.

Do I have no options then? I can leave the fsa crank on my fast new bike and just put the 6800 crank on my old bike. It was still cheaper to buy the whole groupset than buy a 105 crank for it

k-dog

Yep, looks like that's your best option.

The chainset is one of the least important parts anyway. Shifters and dérailleurs are more important.

Check the FD too - my Trek has a band around the seat tube but actually uses a braze on mech that bolts to the band - found that out when I replaced it and had to send the first one back.

Monty Dog

Regular BB30 cranks will not fit 68mm BSA shells, there's simply no room for the bearings. The like of Rotor and BB386 use a longer-spindle such that the bearing sit outboard.

StillGoing

trickytree1984 wrote:

Hi
I recently bought a new Bianchi Sempre pro 105. I have an old Specialized Allez which has Sora. I wanted to upgrade the group on the Spec to 105 5800 but instead decided on Ultegra 6800. The plan is to put that on my best bike (the Bianchi) and move the 105 to the Winter bike (Specialized). Now I already know that I can't move the front mech as it is band on one the Bianchi and braze on on the Specialized. What I do want is to move the chainset.

The Bianchi is bb30 bottom bracket and I want the Shimano 6800 crank on that. No problem, I think you can buy shims for that.

The crank to go on the Specialized is an FSA grossamer (bb30) and needs to go into a standard English threaded (68mm I think). Is that possible in any way?

Many thanks in advance.

Personally, I'd put the Ultegra on the Bianchi, sell the Gossamer and 105 cranks and get something else for your Specialized. As someone else has posted, you can get a clamp to accept your braze on derailleur.

tim_wand

Heracy!!!! Shoot him, Putting Shimano on a Bianchi.

Only Joking , I m having all sorts of fun at the moment moving an Ultegra 6800 Groupset onto a Cannondale Evo with a FSA gossamer BB30 chainset.

I m going to run with the Gossamer and save up for a Cannondale SL BB30 chainset as I ve heard a lot of different reports about the success and integrity of BB30 to 24mm adapters.

If you do go that route . I would err towards something like the Rotor where both halves of the cartridge screw in to one another, rather than adapters that press in.