Bracket racket: what's the bottom line?

I've been spending too much time lurking about on online cycling forums again. I must cut down – or cut it out completely. Maybe. I know that amongst the true gems of genuinely fascinating information there will be the inevitable verbal fisticuffs, misunderstandings and completely random tangents taken. Sometimes I think I post comments just so that I can be annoyed all over again when the original poster – or OP – fails to acknowledge my cycling erudition. The latest topic – actually two – I really mustn't allow myself to get drawn in to includes the advantages and disadvantages of Outboard Bottom Bracket Bearings or OBBB – or OBB. (Just be careful if you call them External Bottom Brackets or your abbreviation could clash with the one used for Eccentric Bottom Brackets and you'll be misunderstood and go and upset someone else no end.) I expect that the excessive use of abbreviations is a feature of most if not all such areas of specialist interest.

Bottom Brackets

From front: square taper, ball race cages; square taper, cartridge bearing; Octalink bottom bracket, cartridge bearing; Hollowtech II, external bottom bracket bearing

Are the more recent innovations an improvement on the old ways? Dunno. I just usually end up buying another tool for whatever version turns up on my latest bike. But perhaps a more pertinent question even for a hoarder such as me should be why, if they have been taken out of my various bicycles and replaced with new ones, do I still have a pile of the buggers taking up space in the garage?

5 comments on “Bracket racket: what's the bottom line?”

  1. Patrick wrote:

    I've got a few old Hollowtech II in the garage as well. I've forgotten why I kept them. Probably because I replaced 'em just in case, having read the 'disadvantages' threads. I have also replaced some square tapers for Hollowtech because I don't agree with the alleged disadvantages. LOL

    I do prefer the external BB concept – the stiffness and ease of replacement – and having held the square tapers in my hand they seem a horribly heavy lump of metal. Old tech, it feels like, but that's an attraction to some people (I enjoyed watching Guy Martin on TV the other day, learning to rebuild old steam locomotives – it's a cultural thing I suppose).

    I've never had a Hollowtech fail prematurely, i.e. after a thousand miles or so, but I would accept they might wear out faster than square taper. Anyway I'm sticking to what I'm used to, which I think is what most cyclists do. I've given up contributing to forums on this subject because it just keeps on coming up and hardly anyone changes their mind.

    Good pic BTW.

  2. Chris wrote:

    Okay. My first external bottom bracket bearings lasted a year. They were Tiagra. I replaced them with an upgrade – Ultegra 6700. They lasted three years before being replaced earlier this year. Although the Ultegra ones were obviously an improvement I do think that three years is still poor, really.

    However, given that I can pick up replacements for not much more than a tenner online I'm not going to worry too much. Leaving aside the possibility that external bottom bracket bearings are a design failure there are two possibilities that might explain why they only lasted for such a short period:

    1. the bottom bracket area of the frame is not faced properly
    2. the bearings were installed with too much or too little torque

    However (again), I think that I prefer the idea that the tool (okay, another expense) to remove/install external bearings fits on the outside of the bearing assembly, so has a correspondingly larger surface area to get good purchase.

    When I removed the Octalink bottom bracket sealed bearings I had to borrow a neighbour's socket and yard-long extension bar to fasten on to the removal tool. There wasn't actually anything wrong with the Octalink bearings – I just needed a different sized one when I installed a new chainset that threw out the chainline on that mountain bike. When I needed another square taper cartridge bearing fitted to my touring bike – also for chainline reasons – I gave up an took it to a bike shop and let them deal with it.

    If you have the right tools I think it is much easier to remove the crankset on a bike with an external bearing systems compared to one with a square taper system. Again, it could well be my poor maintenance skills to blame, but I had one near-side crank hanger on a square taper chainset crack around the axle (too tight?) and the replacement one round off inside (too slack?). Maybe the external bearing system is more tolerant of the home mechanic's mediocre skills. Unless those two little bolts aren't torqued up by the right amount...

    So, external bearings: not perfect, but certainly much easier to replace and not too expensive. Oh, my latest road bike has press fit bottom bracket system. More tools, or more probably a trip to the bike shop when a replacement is called for :???:

  3. Kern wrote:

    Personally, I think the best bottom bracket is the one in the bicycle frame.

  4. Hilary wrote:

    Bottom brackets are something I prefer to leave to someone who knows what they're doing – especially since I managed to snap the crank bolt the last time I tried to mess with one.

    I do spend quite a lot of time lurking on CTC forum and YACF. I don't often post and steer well clear of technical discussions!

  5. Patrick wrote:

    Kern wrote: Personally, I think the best bottom bracket is the one in the bicycle frame.

    Bottom bracket seems a strange term. There is no bracket anywhere near the bottom, is there? There's a spindle, bearings, and tubes but no actual bracket.

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