From square taper to outboard bearings - DISADVANTAGES?

[Jezrant]

I’ve posted about a Raceface X-Type bottom bracket before. The one that came with my Orange MTB probably did less than 1000 miles before it started to become rough. The right-hand (DS) bearing still turned smoothly, but the left-hand (NDS) nearly seized up. I popped off the top cap and the seal and found some greasy gritstone paste in there. Upon closer inspection, the balls looked knackered. I replaced it with a Hope bottom bracket, which was more user-friendly. The Raceface had a brittle plastic top cap that was hard to remove and (re)fit without breaking it, but I understand that Raceface has since redesigned the top cap using a more pliable plastic less prone to cracking when replacing the bearings. If anyone wants it for the cost of postage, drop me a PM. Could be useful for spares (DS bearing is fine) or scientific research for the Common Good. Replacement bearings and top caps are available cheaply.

[JohnW]

I'm old enough, and I've been cycling long enough, for the traditional bottom brackets to have been the norm for me..........you remember - separate fixed and adjustable cups, lockrings, two million balls to each side and a separate square-taper-ended axle. On the quality ones the ball races on the axle and in the cups were precision ground and properly greased and set - and periodically cleaned, greased and readjusted, would last for scores of thousands of miles; 70,000 to 80,000 miles is no exaggeration. The quality ensembles with the precision ground bearings were very expensive, and the current system whereby you just fit the BB cartridge as one unit and ride it until it breaks itself to pieces (after about 10,000 - 15,000 miles in my own experience) and then needs complete replacement are probably no more expensive in the long term, and are certainly more convenient.

OK - so you rode for twelve hours in torrential rain on them, and water got in.......so you opened them up, dried them, cleaned them, regreased them and reset them........it was the norm and we knew where we were with them. They didn't claim to be sealed - but do any sealed BBs actually live up to their name (actually, I have ridden Nimrod BBs, which I believe are Czechoslovakian) and they have proved to be effectively sealed.

There were always differences in taper and taper-end dimensions, both before cartridge BBs and since but the position wasn't as complicated as it seems to be with the various types of outboard bearing ensembles, and with the square taper cartridges there were generic BBs available which were compatible with several crank manufacturers.

There is quite a lot of technical discourse above, which is good of course, but my question was a simple one, and by which I meant how do outboard BB ensembles compare with traditional taper-end BBs in terms of reliability and longevity? My hunch, from what I hear, is that, stiffness notwithstanding, outboard bearings are an unreliable, short lived disadvantage. That'd be acceptable to a certain extent if the manufacturers weren't apparently phasing square taper BBs out on favour of their own (inferior?) designs which are incompatible with other manufacturers and which they can update/change at will to force us to buy a complete groupset when one, possibly minor, component wears out.

This has been the situation with STI type brake/gear-shift levers..........but that's another matter.

At the moment, and probably in my ignorance, the only square taper 22-32-44 (ish) square taper chainsets that I know of are the Spa ones. Bless them - they continue to provide a service to cyclists, as opposed to those who see us as cash cows and exploit us for their own benefit.

Anyway, enough of me grinding my axe - do outboard bearing BBs give the same standard of service and reliability as the square tapers we've spent a lifetime riding with no problems. They weren't broken, so why have those who are after our money set about mending them? (That answers itself really, doesn't it?)

[reohn2]

I'm trying to be as objective as I can on this subject but(there always is one).What use is a component such as OBB's if they have to be a)carefully assembled with exacting preloads,etc,etc and b) need stripping,seals removing,cleaning and regreasing,then reassembling to a) spec,everytime it sees some all to regular UK weather?
On the plus side the system is a little stiffer,which can be noticeable to some heavier and or stronger riders but generally isn't appreciated by most.
I'm not going into ease of chainset removal issues for cleaning,as it's a completely moot point IMHO.

TBH I'm truly baffled ,especially when there's a very good weatherproof,long lasting,cheap,well proven,alternative that other than for a very small loss of stiffness/efficiency,is almost fit and forget.
I enjoy bicycle maintenance but don't like having to molycoddle my machines to that kind of degree,so an honest question.
Where(for ordinary folk)is the gain in OBBs?

EDIT:- Typing at the same time as JohnW and didn't(deliberately)mention the 'cash cow' issue,but now the cat's out of the bag.......

[meic]

I'm old enough, and I've been cycling long enough, for the traditional bottom brackets to have been the norm for me..........you remember - separate fixed and adjustable cups, lockrings, two million balls to each side and a separate square-taper-ended axle. On the quality ones the ball races on the axle and in the cups were precision ground and properly greased and set - and periodically cleaned, greased and readjusted, would last for scores of thousands of miles; 70,000 to 80,000 miles is no exaggeration. The quality ensembles with the precision ground bearings were very expensive, and the current system whereby you just fit the BB cartridge as one unit and ride it until it breaks itself to pieces (after about 10,000 - 15,000 miles in my own experience) and then needs complete replacement are probably no more expensive in the long term, and are certainly more convenient.

OK - so you rode for twelve hours in torrential rain on them, and water got in.......so you opened them up, dried them, cleaned them, regreased them and reset them........it was the norm and we knew where we were with them. They didn't claim to be sealed - but do any sealed BBs actually live up to their name (actually, I have ridden Nimrod BBs, which I believe are Czechoslovakian) and they have proved to be effectively sealed.

There were always differences in taper and taper-end dimensions, both before cartridge BBs and since but the position wasn't as complicated as it seems to be with the various types of outboard bearing ensembles, and with the square taper cartridges there were generic BBs available which were compatible with several crank manufacturers.

There is quite a lot of technical discourse above, which is good of course, but my question was a simple one, and by which I meant how do outboard BB ensembles compare with traditional taper-end BBs in terms of reliability and longevity? My hunch, from what I hear, is that, stiffness notwithstanding, outboard bearings are an unreliable, short lived disadvantage. That'd be acceptable to a certain extent if the manufacturers weren't apparently phasing square taper BBs out on favour of their own (inferior?) designs which are incompatible with other manufacturers and which they can update/change at will to force us to buy a complete groupset when one, possibly minor, component wears out.

This has been the situation with STI type brake/gear-shift levers..........but that's another matter.

At the moment, and probably in my ignorance, the only square taper 22-32-44 (ish) square taper chainsets that I know of are the Spa ones. Bless them - they continue to provide a service to cyclists, as opposed to those who see us as cash cows and exploit us for their own benefit.

Anyway, enough of me grinding my axe - do outboard bearing BBs give the same standard of service and reliability as the square tapers we've spent a lifetime riding with no problems. They weren't broken, so why have those who are after our money set about mending them? (That answers itself really, doesn't it?)

I am not entirely sure as I only have one external BB bike but I think the opposite is true in practice.

There is a lot more interchangeability in the new system than the old, look at this UN55 and the options available.

That would be covered by just four external BBs, all you need to consider is threading (English v Italian) and width* (68 v 73)

About 90% of my fellow riders would be fine with this BB.
http://www.chainreactioncycles.com/shim ... -prod50450


*and I am not even sure that these are not interchangeable anyway

[reohn2]

Meic
So it is a 'cash cow' issue in that the manufacturers don't wish to have a variety of BB axle lengths or the two thread and taper differences?
Whereas if they got their heads together way back when,those 10(?)different S?T variations could have been whittled down to perhaps 5 lengths at most with one common BB shell width!

I thought a consumer/capitalist society served the people,in that manufacturers give the customer what they wanted

[meic]

It is nobodies' interests to have the different axle lengths and tapers.

You could more reasonably argue that the old system was the cash cow.

The different types of external BB shells are needed to fit the different bike frames, another layer of choice occurs with spline types and yet another with axle lengths on the previous systems.

My recent purchase of a load of bearings at £1.25 each means this cow will not be yielding much milk for a few decades.

Also I can carry spare BB bearings weighing only 22g each that could be made to fit any of the bikes in the group with no specialist tools.

[reohn2]

It is nobodies' interests to have the different axle lengths and tapers.

You could more reasonably argue that the old system was the cash cow.

The different types of external BB shells are needed to fit the different bike frames, another layer of choice occurs with spline types and yet another with axle lengths on the previous systems.

How's that then,if as I posted they got their act together,decided on a common BB shell width,and taper,it then narrows things down to a few,say 5(or less) axle lengths.
I buy the BB length to suit my common taper,common BB shell width(70mm?)and the shopowner picks one of those five possibles from the shelf behind him/her,no teeth sucking or sharp intake of breath needed,and both parties are happy as s/he doesn't need as much money tied up in stock,profit is realised without headache and life is simpler.
The same could be said for all of the drivetrain components,just brand differences to fight over,oh! could life be that simple...... ..........wait a moment it was.........

My recent purchase of a load of bearings at £1.25 each means this cow will not be yielding much milk for a few decades.

Also I can carry spare BB bearings weighing only 22g each that could be made to fit any of the bikes in the group with no specialist tools.

Yeah but,you like me,are an anorak,we twiddle with bikes endlessly as part of our hobby,there are those that take a bike to a shop to have it serviced or have a puncture mended or wait for 'the service car'.That's the future we are being funnelled into,you and a few more on here are bucking the tend,one way or another,but when the dust settles bang for buck and outright reliability/longevity,S/T is the answer,which is being quietly shelved in the name of 'progress' and the suckers are falling for it hook line and sinker..........
All IMO of course

[meic]

Yes I can see the attraction to the cycle trade of regular replacement of EBB shells a job which takes a few minutes, charge £40 for fitting a £10 shell.

If you overtighten it just a tiny bit they will be back twice as fast.

Much easier than getting fifty quid for extracting a seriously seized UN72 every decade.

One point about all the common BB options is that they are all fairly cheap and reliable.
I would never expect my UNXX to fail on a tour and I would not even bother carrying the 22g bearing for my external BB, you get plenty of warning before replacement is needed.

[MartinC]

I'm happy that OBB s are stiffer and lighter than ST ones. It's just that ST is stiff and light enough for most of my bike usage, if I were racing it would be different. I don't think it' a conspiracy by the bike manufacturers - their market is largely driven by their customers perception that the technology for competitive riding is best for them. I'm sure they encourage them in that though.

I think that an OBB in a standard BB shell is a flawed design and is just a transient phase in the development of a new BB standard. For a lighter stiffer crankset and BB you need a larger diameter hollow spindle. The only way to squeeze this into a current standard BB shell is to squeeze the bearings into the small gap between the BB shell and the cranks and compromise the bearing size and sealing in the process. Optimistically at some point a new standard BB shell size will emerge with some sensible bearings - but it hasn't happened yet and when it does they'll be a legacy of non-compliant frames. I think old ST BBs will be around for some time yet even if they're deeply unfashionable. Equally so I think OB shells for an old standard BB shell will be available too. I wouldn't buy a frame with one of the proprietary standard BBs unless I only intended to keep it a year or two.

One of the useful things a ST BB allows you to do is fiddle with the chainline by varying the width - very useful if you want to change a bike to SS, fixed or IGH. I've got mixed feelings about the old cup and cone ones though - the satisfaction of being able to adjust and maintain them palls quickly when one loosens itself on the road.

[JohnW]

I am not entirely sure as I only have one external BB bike but I think the opposite is true in practice.

There is a lot more interchangeability in the new system than the old, look at this UN55 and the options available.

That would be covered by just four external BBs, all you need to consider is threading (English v Italian) and width* (68 v 73)

About 90% of my fellow riders would be fine with this BB.
http://www.chainreactioncycles.com/shim ... -prod50450


*and I am not even sure that these are not interchangeable anyway

I'm not as familiar with the vagaries of all the outside bearing BBs, so my response to this is limited - and I'll have to look further into it all, but which axles/spindles are compatible with the OBBB in the advert? Are other manufacturers' axles/spindles compatible with it? No doubt the manufacturer's own axles/spindles will fit, but which cranks are compatible with the axle/spindle? And when many of us have finally converted and their sales begin to drop off, will the manufacturer make an impossibly subtle change to their product to make last year's output incompatible with this years? - and we all have to buy complete groupsets?.............it's been done on other components..........

Straight away there are three interfaces and compatibilities to be researched here (and cause problems), rather than the two on the square taper system.

I'm open minded to what you say meic - in fact if OBBBs eventually become as inter-compatible, reliable, long-lasting as the ensembles we're used to they won't be such bad news, but I still don't think they needed inventing.

A similar case is the change from screw-on hub/block ensembles to freehubs. There is a definite advantage with freehubs, in that the bearings on the block/cassette side are at the same distance from the dropout as at the other side and there is very significantly less tendency for the spindles to bend and break. The downside is that, when a chain needed replacing on the screw-on system, the freewheel block included a new freewheel so you had to buy two things to do the job. Now, the freewheel mechanism is a separate component from the block - the cassette is separate and slides onto the freewheel mech, so whilst the freehub is said to outlast a cassette several times over, eventually there is a third component to buy when previously only two needed to be bought. Whether or not sealed bearings are really sealed is doubtful but another question and I cannot get any of the distributers to talk to me about how many miles we can expect from a freehub's freewheel mechanism. The thing is that with the freehub there is an advantage, and it's a balanced decision (or it would be if the manufacturers weren't phasing freewheel blocks and screw-on hubs out, thereby depriving us of the choice).............but I don't see a benefit in OBBBs - and no-one can explain one to me.

[meic]

Are other manufacturers' axles/spindles compatible with it? No doubt the manufacturer's own axles/spindles will fit, but which cranks are compatible with the axle/spindle?

I suspect that you havent actually had a look at an EBB system.

The axle is part of the right hand spider, they commonly have 24mm axles and the BB shell that I linked to has a 24mm hole through it.

You just slide the axle through the holes in the shells, slide the left crank on the axle and adjust with an end cap then tighten up with two pinch bolts.

I am not a fan of EBB especially, I bought one in ignorance because it was cheap. Having already got it I have learnt about them and how to cope with them rather than just knocking them from the fringe.

I think I would advice people to go ST unless something else made an EBB a much better option.
They are not as bad as their deriders make out but it is very hard to beat a ten pound UN55 that lasts so long you have to remove it from the frame only to prevent it welding in with old age.

My EBB set cost only £40 and I think weighs less than ST systems costing ten times that.

[JohnW]

..................

1). I suspect that you havent actually had a look at an EBB system.

2). I am not a fan of EBB especially, I bought one in ignorance because it was cheap. Having already got it I have learnt about them and how to cope with them rather than just knocking them from the fringe.

3). I think I would advice people to go ST unless something else made an EBB a much better option.

4). They are not as bad as their deriders make out but it is very hard to beat a ten pound UN55 that lasts so long you have to remove it from the frame only to prevent it welding in with old age.................

1). You're right meic - I'm not familiar with it myself.
2). That says a lot.
3). That says even more - in fact it says it all,
4). I'm not a derider myself because I don't have any experience of them, but the sight of one on the floor of my local LBS (and his language on removing it) and the experience of one of my cycling colleagues leads me to resolve that I won't ever get near enough to one to learn enough to be able to rationally deride them.

[meic]

I suspect your mechanic was an "old school" guy showing typical disdain of the unfamiliar technology.
We tend not to notice the difficulties involved with the things that we are used to dealing with and make much more out of the oddities of more foreign things.

As an example

viewtopic.php?f=5&t=89444

This just wouldnt happen with EBB systems. If EBB were the old technology and ST the new technology that would be considered adequate reason never to touch such a stupid design where any damage to a soft square taper hole in an aluminium spider would mean the crank/spider needed binning.

Likewise the applying preload to the crank on the end cap is not something they are used to (though they manage with wheel bearings ), at least you dont have to do it with shims like on my BMW axles which is a real PIA but does prevent incompetent grease monkeys from wrecking the bearings.

[JohnW]

I suspect your mechanic was an "old school" guy showing typical disdain of the unfamiliar technology.
We tend not to notice the difficulties involved with the things that we are used to dealing with and make much more out of the oddities of more foreign things.................

Well no, actually meic - that's not a fair comment - he is a guy who moves with the times and generally is very quickly au fait with developments.

I don't know how many manufacturers produce half-shaft BB spindles, attached to the cranks - so it may not have been the actual type that you refer to. I'm not absolutely sure of the details, so make of this what you will, but as I understood it the sealed bearing had collapsed within itself shortly after the bike was purchased (from another, on-line retailer I believe) and it had caused grooving and unusual damage to other parts. It may have been badly fitted in the first place. The uncomplimentary comments were because spare parts for this particular ensemble were difficult to get.

As an aside, there are two LBSs in my area who only sell a very limited range of ready-built bikes because they say they make more money from putting to rights ready-builts that customers have bought from on-line retailers and can't get to work properly.

[meic]

Then my limited knowledge is showing, I did say I only have the one EBB on one bike.

I have heard of these split axle types but not seen them in the flesh or pictures. I dont even know who makes them
I would say that is like somebody condemning Square Tapers because of a bad experience with an Octalink or even Cotterpins!

These foreign things all look alike from one side of the fence. Possibly from the Hollowtech II side of the fence they appear to be on the same side as square tapers.