FSA BB replacement / Bianchi

[gbb]

Became aware today particually, but it was just noticable the other day...a knocking when applying pressure to the drive side crank, at 1 oclock.
Looked at it tonight...oh yes...some considerable play in the outboard BB allowing the crank to wobble.

So...anyone changed them ? I got a BB wrench, might even whip them out and have a look ?

Clockwise or anticlockwise to remove them ?
Have you replaced just the bearings or the whole cartridge.
Any thoughts appreciated

 

[twentysix by twentyfive]

Hmmph - "old" style BB's on the drive side were always LH thread. I don't think that will have changed for external BB's. It's a wind it on tight thing with the crank rotation rather than a wind it off design. But I've never owned one..........

 

[jpembroke]

Fairly easy to replace. Undo pinch bolts on LH crank, undo the crank bolt, remove LH crank and push out the RH crank/chainset (you may need to give it a tap with a rubber mallet to push it through the BB shell). External cups are straightforward to remove but you need to establish if they are BSA or Italian threaded (it is a bianchi after all). Italian threaded are normal threads both sides; ISO (most bikes these days) are normal threaded LH side and reverse threaded on RH (drive) side.

A word of advice about FSA external BBs: they have a very poor reputation (look at reviews on roadbikereview.com). I have one on my 'cross bike and discovered that it's very easy to overload the bearings when tightening the LH crank. The crank bolt (the one that goes through the axle hole of the crank, not the pinch bolts) is tightened with a 5mm allen wrench and many people tighten it way too much. Unlike Shimano HTII systems, there is no stopper on the axle so you can merrily keep tightening until the whole thing binds up and the bearings get damaged (also Shimano have this little plastic cap rather than a bolt, which is hand tightened using a small round plastic disk - you can't overtighten it if you tried). Having learnt the hard way, now I use a long 5mm allen wrench but tighten with the wrong end (i.e. the handle end, the bit you normally hold on to). This means I can't apply too much leverage. Obviously a torque wrench is preferable, but this seems to work fine.

Tutorial here:

http://www.parktool.com/blog/repair...xo-giga-x-pipe-x-type-campagnolo-ultra-torque

Hope that helps

 

[gbb]

Thanks JP...
Ref FSA bb quality, i had read they're not top notch, but there you go...
The 5mm bolt, ive had my cranks off a couple of times when deep cleaning. It did occur to me about overtightening. Dont think i have because i figured the pinch bolts would help retain the clamp bolt anyway.

Its surprising how the bearings gone. No roughness, no medium or long term symptoms, just a fair amount of slop...but then, i had a fall on ice today, perhaps when the drive side crank hit the floor its put a whole load of stress through the bearing. We (the bike and me) went with a fair bang.

 

[gbb]

A coupe of questions i don't think i'm going to get answers for...
Took the cranks off tonight. One thing that jumps out at you straight away is the bearing cover (that keeps debris from the bearing) is a top hat style. (its got Megaexo 19mm dia on it)
I don't get it ??? The crank spindle doesn't run on the bearing, it runs on the tophat section of this bearing cover, which runs on the bearing. Surely a piece of plastic isn't a running surface between the bearing and the spindle?

Looking at a tutorial ref replacing bearings, they state that some BBs have this tophat bearing cover, some a flat bearing cover. I just can't believe there is a piece of plastic between the bearing and the spindle.
If it wasnt there, the spindle slops about in the bearing.

Someone out there must have stripped these before ???

Is this the reason Megaexo BBs are regarded as crud ?

Bikes off the road now, so any input appreciated. I want to get it up and running ASAP. Bearings are no problem...just want to get anyones thoughts.

 

[gbb]

Update...5 minutes after my last post
I really wonder how many people replace the whole BB when its just the tophat washer thats cream crackered !!!
Just looked at the non drive side...bearing spins ok ish (there's a tiny bit of roughness), the driveside bearing runs ok. There's no play evident in the bearings at all, not that would allow the crank to wobble.

I'm looking at it...now i can see whats happened. The non drive side tophat cover has split and allowed the tophat section (basically its now a piece of tube) to fall into the BB cavity. So the crank now slops in the bearing because there's nothing to support it.
I reckon a pair of new bearing covers will sort it. I'll flip out the actual bearing seals and flush and regrease them.
All i have to do now is find someone that sells the tophat covers.

It could be that i spend maybe £5 to £10 for some new covers...as opposed to £40 to £50 for a new BB.

Any thoughts still appreciated.

Edited to say...£6.90, postage included for two new covers from UKbikestore. I'll keep you posted once they come. Could be a cheap fix.

 

[gbb]

Just musing really..
Tophat bearing covers came promptly from UKbikestore...many thanks to them.
Obviously, to get the bearings out of the cups, you're supposed to have a special extractor..no doubt expensive, so i've fabricated my own (in about 15 mintes ). No big deal with the right materials ...basically a short length of steel tube with the same OD as the cups, a large heavy washer at the bottom, a bolt and nut, and another heavy washer that sits inside the cup and on top of the bearing. The theory of extracting blind bearings is simple enough, its what i do at work with bearings in conveyor rollers. I'll post some pics later, it extracted the bearings very easily. I'll just reverse the assembly to install the new bearings.
Hopefully, with the help of a friend in the industrial supplies industry, i'm getting some hybrid ceramic bearings to upgrade the cups at cost price.
The bearings are 6804-2RS (standard) or 6804-2RZ (IIRC..or maybe 2RW) which have low friction seals, or the ceramic hybrids which are the best obviously.
Alternatively you can get 61804 deep groove bearings which reputedly have a longer service life, so plenty of options.

You can buy the standard bearings for less than £2 each !!!! so you could replace bearings and covers for less than £10.

Most people couldnt be bothered with the faffing about, but i love a challenge.