External Bearing Bottom Brackets- RUBBISH!!!

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Milfred Cubicle
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External Bearing Bottom Brackets- RUBBISH!!!

Postby Milfred Cubicle » 29 Mar 2009, 8:56pm

Is it just me, or are these new style of B.B. absolutely rubbish? I've got two bikes, one with a Truvativ system, the other with Shimano. I'm fastidious with keeping my bikes clean, never use a hose, but the damned things seem to fall to bits in less than a 1000 miles! My local shop has checked if the frames need facing (no), and have suggested I try a Hope stainless/ceramic bearing setup. At at least £65, its not cheap.
To put it into perspective, I've got an old bike with a U.N 71 Shimano internal, and I reckon it's done well over 5000 miles, and is fine. I suspect this is just another case of giving us a tiny 'performance' advantage, and ofsetting it with a very limited lifespan! I'm considering going back to good old square taper, despite the various horror stries I've heard, but suspect are just marketing drivel!
Alternatively, my local bearing supplier can get quality bearings to fit, at £6-8 a pair! Has anyone tried to remove them from the cups? I'm going to give it a go, by gently warming the cups, then pressing out the bearings. At the rate they wear out, it would be cheaper to buy myself a lathe and make my own!

gbnz
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby gbnz » 29 Mar 2009, 10:43pm

They're not rubbish! Modern cycling components are designed to fail in as short a time as possible and it sounds like these are fulfilling their design criteria. Where possible I've retained "outdated" systems I.e. ISO square taper bottom brackets and in some instances have actually reverted to older component types. I've no interest in replacing any of my bikes, after a couple of rides

The other particularly satisfying route, is to make full use of manufacturers warrenties. A number of manufacturers have supported their products with extensive warrenties, fully aware that in this day and age, only a minority retain receipts and routinely return their dubious products for replacement. While historically I've never bothered keeping receipts or claiming under warrenty, the lack of durability of most modern cycling components has led me to file each and very receipt away. I know full well that when I buy a brand new wheel, hub,pedal, inner tube etc, etc it'll fail in a fraction of the period it should. At least now I have the satisfaction of replacing the components on my bike FOC on an annual basis
Last edited by gbnz on 29 Mar 2009, 10:46pm, edited 1 time in total.

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speedsixdave
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby speedsixdave » 29 Mar 2009, 10:44pm

Milfred Cubicle wrote:Is it just me, or are these new style of B.B. absolutely rubbish?


Yep! A truly half-arsed 'engineering solution'.

The logic works like this:

1: We desire lighter cranks and bottom bracket.
2: A good way is to use a thin-walled hollow axle.
3: To make a hollow axle light and stiff enough, it needs to be oversized.
4: An oversized axle leaves insufficient room inside a 33mm bottom bracket shell for decent bearings.
5: Presto - put the bearings outside the shell!

It works fine in a lab, but is obviously a rubbish idea. Obviously. You only have to look at a bike that has been ridden to see how much crap accumulates around the bottom bracket area, so why would you put a bike's primary bearings into a place where they are more exposed than they were before? Ridiculous!

Now there's nothing intrinsically wrong with the oversized BB axle - lighter and stiffer, with a better retention method, is a good thing. But the technology can only work well in a BB shell of somewhat greater internal diameter, so that we can keep the bearings inside the shell, and protected from the elements.

A larger diameter BB shell is also intrinsically a good idea - that whole part of the bike can be built stiffer, with greater surface area for welds or brazing if required. But it does necessitate a whole new standard for the bottom bracket. And despite a few attempts by different manufacturers, no standard has yet emerged.

External bearings are a stupid half-way house, an attempt to retrofit bits of new technology to unsuitable legacy standards. They will mostly disappear on new bikes in a few years' time, just as quill stems have mostly disappeared.

PS: There will be continuing support for tapered BB axles in 33mm shells among some folk, because it it tried and tested technology. Which is all fine - so are quill stems, which even have certain advantages over Aheadset designs. But continuing micro-evolution will eventually replace this ancient technology with something else, and create a few dead ends on the way. We just have to hope that the eventual evolutionary winner will be a real improvement - like index gears, STIs, clipless pedals, decent clincher tyres and freehubs - and not a new problem, like 12-spoke wheels, 11-speed gears, and external bearings.
Big wheels good, small wheels better.
Two saddles best!

drossall
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby drossall » 29 Mar 2009, 10:59pm

speedsixdave wrote:We just have to hope that the eventual evolutionary winner will be a real improvement...


We just have to hope that it will be something standard. You used to get interchangeable gears, freewheels, cranks, the lot, all the same sizes for years. Now your Shimano freehub doesn't fit your Campag cassette, levers and gears don't work together, spindles don't fit cranks, and if you walk into a bike shop and ask for a spare for last year's model they look at you as if you came from Mars.

ianr1950
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby ianr1950 » 30 Mar 2009, 9:38am

Don't see any problem at all with them.

I have 2 bikes with them, both done over 3000 miles in all weathers and still working perfectly.

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speedsixdave
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby speedsixdave » 30 Mar 2009, 12:47pm

ianr1950 wrote:I have 2 bikes with them, both done over 3000 miles in all weathers and still working perfectly.


Yes, but that doesn't mean they're not bad engineering and a bad idea. Lots of people did lots of miles in Ford Pintos without the fuel tanks exploding due to rear-end collisions, but that doesn't mean that wasn't extremely bad engineering. If you can't do 3000 miles on a bottom bracket, it really doesn't deserve to be called engineering at all!
Big wheels good, small wheels better.

Two saddles best!

gilesjuk
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby gilesjuk » 30 Mar 2009, 1:14pm

You hear this all the time. Someone tries one or two versions of a component then writes off the entire system as a result.

People seem to write off square taper and ISIS for various reasons too.

glueman
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby glueman » 30 Mar 2009, 1:20pm

Another attempt to make an inately unsexy bicycle component attractive. See integrated headsets, insufficiently spoked wheels, etc.

ianr1950
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby ianr1950 » 30 Mar 2009, 1:50pm

speedsixdave wrote:
ianr1950 wrote:I have 2 bikes with them, both done over 3000 miles in all weathers and still working perfectly.


Yes, but that doesn't mean they're not bad engineering and a bad idea. Lots of people did lots of miles in Ford Pintos without the fuel tanks exploding due to rear-end collisions, but that doesn't mean that wasn't extremely bad engineering. If you can't do 3000 miles on a bottom bracket, it really doesn't deserve to be called engineering at all!


But it also doesn't mean that it is bad engineering, have I said that it has only lasted 3000 miles. The Op said that his has only lasted 1000 milesAs I have said mine have done over 3000 miles each and no sign of any failure yet so why does that mean that it is bad engineering.

ianr1950
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby ianr1950 » 30 Mar 2009, 1:55pm

glueman wrote:Another attempt to make an inately unsexy bicycle component attractive. See integrated headsets, insufficiently spoked wheels, etc.


I don't see that wheels with less than 36 or whatever spokes is unsufficient. It all depends on what you want the wheels for and just because whoever wants a wheel that is fast but it has less than the number of spokes that someone else deems as the absolute minimum does not mean that they are purposely made that way for attractiveness.

There is nothing wrong with integrated headsets as far as I can see.

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patricktaylor
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby patricktaylor » 30 Mar 2009, 2:25pm

Why is an external BB bearing bad engineering? It's still enclosed by its casing. Also, the bearings are closer to the cranks, which seems like good engineering.

gbnz
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby gbnz » 30 Mar 2009, 3:25pm

ianr1950 wrote:
glueman wrote:Another attempt to make an inately unsexy bicycle component attractive. See integrated headsets, insufficiently spoked wheels, etc.


I don't see that wheels with less than 36 or whatever spokes is unsufficient. It all depends on what you want the wheels for and just because whoever wants a wheel that is fast but it has less than the number of spokes that someone else deems as the absolute minimum does not mean that they are purposely made that way for attractiveness.quote]

I've found the quality of the wheel building and components often counts more towards durability, than the number of spokes (Though obviously I wouldn't attempt to carry 150kg on a 16 spoke wheel) . I've 16,24, 27, 32 and 36 spoke wheels. The 16 and 27 remain perfect after considerable mileage, one of the 36 spokes was significantly out of true after 6 weeks use (It was cheap, but not that cheap- mavic rims, shimano hubs)

pigman
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby pigman » 30 Mar 2009, 3:42pm

ianr1950 wrote:
glueman wrote:Another attempt to make an inately unsexy bicycle component attractive. See integrated headsets, insufficiently spoked wheels, etc.


I don't see that wheels with less than 36 or whatever spokes is unsufficient. It all depends on what you want the wheels for and just because whoever wants a wheel that is fast but it has less than the number of spokes that someone else deems as the absolute minimum does not mean that they are purposely made that way for attractiveness.

There is nothing wrong with integrated headsets as far as I can see.

a component that uses the mainpiece its supposed to support as the wear medium is in my opinion poorly engineered. With int h/sets, the frame itself acts as the bearing races. when that wears, youre knackered. But int. h/sets are light, cheap to make, easy to fit and aesthetically pleasing, so there are certain advantages.

Here's my take on wheels (copied in from another forum where I had my moan...
Got the road bike out last weekend. Its got 20 spoke (I think) ksyrium elites on it. Suddenly the bad memories of them came back - deep section rims provide lots of vertical stiffness, but too few spokes provide no lateral stiffness. Then the back one's always going out of true. Plus if I sprint, I can get the tyre to rub the chainstay. And they've probably not done 1000 miles. oh and cross winds are a bugger, with the bladed spokes. So, i toyed with the idea of going back to trad spoked wheels, but the ksyriums did cost a lot and weight on wheels is the most important aspect. so I weighed them. Ksyrium elites v XT hubs on 32 spoke 3X mavic open pros. Guess what? The 32 spokers weigh 75 grammes each more, so thats 150g in total and thats with a rim tape, which the ksyriums dont use. So job done, I'm back to traditional wheels with the sexy ones relegated to time trial use, should I ever bother. Talk about marketing clap trap
Ive used the 32 spokers on the clubrun yesterday and didnt go noticeably slower.

Lots of this performance v durability is probably ok for lance et al who replace bits & bikes after a couple of weeks, have dedicated maechanics and are fully supported by mavic, shimano etc.

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hubgearfreak
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby hubgearfreak » 30 Mar 2009, 4:12pm

pigman wrote:Ive used the 32 spokers on the clubrun yesterday and didnt go noticeably slower.

Lots of this performance v durability is probably ok for lance et al who replace bits & bikes after a couple of weeks, have dedicated maechanics and are fully supported by mavic, shimano etc.


good man - you'll soon be out in jeans and flat pedals with the best of us :mrgreen:

these higher performance improvements that keep cropping up may well be fine for lance et al, but the main beneficiaries are the manufacturers. every time they get someone to buy a non steel frame, 16 spoke wheel, STI levers, clipless pedals or whatever, they're laughing at yours and the environment's expense.

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patricktaylor
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Re: External Bearing Bottom Brackets- RUBBISH!!!

Postby patricktaylor » 30 Mar 2009, 4:43pm

This thread is about external bearing bottom brackets = rubbish and falling to bits in less than 1000 miles. So why are they rubbish and what falls to bits? I have one on one of my bikes 4000 miles (including winter) and it's still fine.