FSA Mega Exo Bottom Bracket

bianchibob

I want to replace the FSA Mega Exo bottom bracket on my Bianchi 928 due to wear and an insistant 'clicking' noise.
The bike is running an FSA SLK carbon Compact crankset.
The bottom bracket is a 68mm English thread.

I have heard many reports that FSA bottom brackets are not as well engineered as Shimano, and I was therefore wondering whether I can replace the present bearing with a Shimano 6800 Ultegra set up.
On browsing several web sites I have noted that the crank spindle can be a tight fit in the Shimano bearing, even involving the use of a rubber mallet to get the crank spindle to fit.....this seems excessive and not something I would want to do, as removal for maintenance would then be difficult.

Also the none drive crank has a different form of attachment and preload adjustment than a Shimano crank and this could lead to premature failure of the Shimano bearings with the FSA cranks, due to excessive side pressure.

Any comments or views from members who have experience of this set up would be appreciated.

Calpol

bianchibob wrote:

I want to replace the FSA Mega Exo bottom bracket on my Bianchi 928 due to wear and an insistant 'clicking' noise.
The bike is running an FSA SLK carbon Compact crankset.
The bottom bracket is a 68mm English thread.

I have heard many reports that FSA bottom brackets are not as well engineered as Shimano, and I was therefore wondering whether I can replace the present bearing with a Shimano 6800 Ultegra set up.
On browsing several web sites I have noted that the crank spindle can be a tight fit in the Shimano bearing, even involving the use of a rubber mallet to get the crank spindle to fit.....this seems excessive and not something I would want to do, as removal for maintenance would then be difficult.

Also the none drive crank has a different form of attachment and preload adjustment than a Shimano crank and this could lead to premature failure of the Shimano bearings with the FSA cranks, due to excessive side pressure.

Any comments or views from members who have experience of this set up would be appreciated.

I tried the same a couple of years ago. It didn't fit despite me trying to block/hammer it home. Ended up refitting the FSA one.

rafletcher

You could always fit a Hope GXP BB.

andy_wrx

If you unpick the plastic dirt seals on the FSA with a blade, you'll find that inside are two perfectly standard size bearings.

I'd buy SKF or similar from a bearing factor eg simplybearings.co.uk

bianchibob

andy_wrx wrote:

If you unpick the plastic dirt seals on the FSA with a blade, you'll find that inside are two perfectly standard size bearings.

I'd buy SKF or similar from a bearing factor eg simplybearings.co.uk

Thanks for that, I was wondering if the bearings could be replaced in the 'shells'

You say unpick the plastic dirt seals, can these be replaced with new ones or do you have to replace them after installing new bearings, or do the new bearings come with new seals.

Thanks

apreading

You replace them. You need to be careful about how to remove them so that they dont get damaged. General consensus I think is to use a very small flat bladed scredriver inserted into the big whole in the middle picking up the lip of the opposite side of the dirt seal, using the near side for leverage. Just be gentle, as well as not wanting to snap it, you dont want to make an indent in the edges or it wont work so well as a seal in the future, and the plastic is fairly soft. They should not put up much if any fight to coming off though, so its not hard to achieve without damage.

andy_wrx

I used a Stanley knife blade, IIRC from the outside edge - sharp (ie thin) enough to get in, then wide enough to spread the force as you lever it off : bit of gentle waggling and it just popped off, then pops/clips back in afterwards

Monty Dog

SLK uses a narrower, non-standard bearing vs standard HT2, Hope etc - using one will overload / lead to accelerate wear. You could try popping the seals to see how worn / damaged the bearing are - if they are full of rusty sludge then chances are they need replacing. Removing the bearing from the cup is tricky as removing the bearing will probably damaging it.

desweller

andy_wrx wrote:

If you unpick the plastic dirt seals on the FSA with a blade, you'll find that inside are two perfectly standard size bearings.

I'd buy SKF or similar from a bearing factor eg simplybearings.co.uk

IME they are actually quite difficult to source. The difference between O/D and I/D is quite small; not optimal as you wind up with small balls, high contact stresses and not much room for seals.

apreading

Are they not these: http://www.chainreactioncycles.com/fsa- ... -prod87626

desweller

Depends what version the OP has. IIRC there is a variant where the crankshaft runs directly in the bearing, so uses a 24mm ID. It's been some time (3 years?) since I did mine though.

Monty Dog

Just did a quick Google search to satisfy my curiosity - the SLK BB has an internal spacer tube to prevent over-loading the bearings due to the way the non-drive crank is secured. If you use a HT2 or Hope etc there is a risk of over-loading the bearing because there is no spacer i.e. it will wear-out more quickly.

svetty

Monty Dog wrote:

Just did a quick Google search to satisfy my curiosity - the SLK BB has an internal spacer tube to prevent over-loading the bearings due to the way the non-drive crank is secured. If you use a HT2 or Hope etc there is a risk of over-loading the bearing because there is no spacer i.e. it will wear-out more quickly.

No problem with the Hope BB on my bike - the BB comes with a spacer tube. The only difference is that you fit a thin washer to each cup when using it with FSA that you omit with Shimano HT2 cranks.