Bottom Bracket Considerations

[Jezston]

If there's one part of a bike I know the least about, it's bottom brackets. Or maybe it's headsets? Both of which are mysteries to me, their knowledge a secret closely guarded by bike mechanics, or rather I leave them to it if apparently I ever have any issues with them.

Anyway, as part of my gradual lightweight fixed road bike (misappropriated track frame build based on a Dolan Track Champ frame to be ridden on the road mostly but maybe on the track if I ever find myself living anywhere near a velodrome) I need to decide upon one of these mysterious little widgets to put in my bike never to be touched by my hands nor seen ever again.

So, questions:

Octalink or Square Taper?
Sealed or ... unsealed (?) cartridge?
What are the benefits of spending more?

I guess I'm looking for a sweet spot somewhere between cost, performance, maintainance and reliability and weight. Happy to sacrifice a bit of performance for some lower weight or cost - I'm not looking to win any races on this, but I would like to get something nice light and smooth - and also not too much work to keep running at its best.

Have been recommended Sugino 75 (but have also heard this massively limits what cranks/chainset I can use - has to be Sugino?) and a Phil Wood stainless steel BB which is sealed. I've heard talk arguing against current Shimano and Campag track bottom brackets.

Or should I be looking at road-orientated BB if I'm mostly going to be facing the elements, even if it is on a fixed gear bike?

Oh and I believe the frame takes an English bottom bracket type.

 

[HLaB]

I'm a complete beginner when it comes to BB's too but I think with sealed/unsealed its the same as hubs; if you know what you are doing and maintain them regularly the unsealed will be smoother, if not it'll be 10x harder. I think I prefer the idea of sealed cartridge hubs

 

[RecordAceFromNew]

Imho, unless one is a bb connoisseur or has bb fetish and must have a Phil bb e.g. then generally one should pick one's chainset before one picks the bb (if a choice exists at that point at all). This is because a) one is more likely to care about the features of their chainset than their bb, b) there are far more choices in chainset than in bb, c) bb's are usually less expensive than chainsets, and d) choice of bb for each chainset is limited.

But in this case since you are running a fixie/track frame it might also help to know what the rear dropout distance is (it could be 110m or 120mm or more e.g.), what rear hub you are planning to use, and what chainline you are shooting for (42mm or closer to 40mm?), since the combination of chainset and bb will determine chainline.

Achieving target chainline from plan/spec can get complicated, and not predictable/achievable without trying in some cases due to lacking/conflicting chainset manufacturer info e.g., or the variability in square tapers. Perhaps that is why it might look like a closely guarded secret, when in fact sometimes it is just pure ignorance!

Hope the above fills you with enough confidence...

 

[Jezston]

Oh blimey.

I have no idea what my target chainline is, I didn't even realise I had to create a target to aim for! I'd like it to be err, straight?

 

[RecordAceFromNew]

I'd like it to be err, straight?

Yes you do!

You might want to read this.

 

[downfader]

I cant tell you the specs of them, but on my bikes I have only used Ultegra or Hope BBs. The only other one I'd personally consider is a Chris King. Good bearings, well made units that a good LBS can fit (they did on both mine). Might not suit fixed, so apologies in advance..