Why are bottom brackets becoming so fragile?

supertwisted

Take an old square taper BB, it'll do a trillion miles without a squeak.

Then came outboard bearing BBs, and heaven help you if your shell faces haven't been machined flat or you dare to ride them in the wet.

Now we have pressfit BB30. I've done 50 dry miles on mine and it's creaking and groaning already.

I'm all for reinventing-the-wheel engineering, but at least make it as good as the original.

*exageration may have been used to make my point.

supersonic

Because of our obsession with reducing weight, and increasing stiffness. Also relatively new tech, they will improve.

cooldad

Makes manufacturing speccing etc easier as fewer different models - one BB size and axle length.

johnsav

GXP bottom bracket have never failed for me and are cheap as chips

Ryan Jones

I'm amazed at the problems people are reportedly having with BB30, indeed my Cannondale is a rather creaky affair and I'm convinced it's the BB bearings as the pivots all got greased properly. As it's a standard bearing though, I'd like to see if ones by SKF perform any differently, seeing as they're the last name in bearings.

Raymondavalon

johnsav wrote:

GXP bottom bracket have never failed for me and are cheap as chips

Agreed, got GXP on my all mountain and replaced once in 3 years, ridden in all conditions, mud, rain and dry.
Once you get the tools, replacing an external BB is a 15 minute job, so it's also the sheer convenience of DIY that's a bonus too. GXP BB cups: £20, so not expensive at all

Anonymous

HTII bottom bracket that's on my bike now has lasted almost two years, so it's not all bad.

I can't really say that they last any less than old square taper cartridges. With those things I tended to destroy the crank interface within a few months anyway.

jon1993

my bb30 bottom bracket has gone after 20 miles on my new boardman pro
why couldnt they stick to the older type that actually worked!

junglist_matty

My external Hope bottom bracket hasn't missed a beat.... Always been reliable and no noises.... The RaceFace one that the Hope replaced; well the less said about that the better!

stubs

Having seen my first BB30 bearings recently I am surprised how spindly they are. Would have thought Cannondale would have specced something a bit beefier when they designed it.

As for sealed square taper BBs I can remember when they used to fail all the time and everyone said the old loose ball type was much better. Also the square hole in the crank arm used to wear and become loose very fast, meaning a big bar to tighten the bolt and lots of loctite was needed.

Every new standard takes a few years to become reliable.

P.S got a GPX BB on my Canyon and the drive side bearing is already on its way out after only 400 miles.

gilesjuk

Clueless engineering and a desire to increase the sale of consumables (think printer ink). Square taper BBs have good sealing and reasonable size bearings. It is a mature solution now with years of improvements.

Square taper seems to get a bad rap but I've got no problems with it.

ISIS was invented to solve some of the perceived problems with square taper, but reduced the bearing size and so they wore out fast.

So external systems were invented to increase bearing size to make up for the problems of ISIS. But the sealing is poor on some external systems.

Press fit systems are to eliminate a small problem with bike frames, the threads on the BB shell. They do get damaged and stripped sometimes, but usually by the DIYer.

gilesjuk

jon1993 wrote:

my bb30 bottom bracket has gone after 20 miles on my new boardman pro
why couldnt they stick to the older type that actually worked!

I would imagine that it has been fitted incorrectly. Boardman are sold by Halfords after all.

stubs

gilesjuk wrote:

jon1993 wrote:

my bb30 bottom bracket has gone after 20 miles on my new boardman pro
why couldnt they stick to the older type that actually worked!

I would imagine that it has been fitted incorrectly. Boardman are sold by Halfords after all.

Halfords dont fit the BB though thats all done by the factory.

cee

HT2 for me.

plain old deore works well for 15 quid, but for me....the XT/SLX at around 25 is the sweetspot of price, function and longevity....

In fact...my bb has outlasted a chainset....so now I have the spare that came with the new chainset.

Anonymous

What wore out on the chainset?

VWsurfbum

I have the GXP ones sold by superstar, actually very good for the price!

ddraver

+1 for Hope, They do seem to have got this one right!

hounslow

stubs wrote:

gilesjuk wrote:

jon1993 wrote:

my bb30 bottom bracket has gone after 20 miles on my new boardman pro
why couldnt they stick to the older type that actually worked!

I would imagine that it has been fitted incorrectly. Boardman are sold by Halfords after all.

Halfords dont fit the BB though thats all done by the factory.

and the factory fitted them incorrectly. there has been a couple of memos on the intranet and madison are out of bb30 tools as a result.

cee

yeehaamcgee wrote:

What wore out on the chainset?

It was a combination....

chain rings had hooky teeth....gear slippage....ok, could have got new rings....
I snapped a pedal off on a poor landing landing, leaving the pedal threaded insert, inside the drive side crank arm....then, whilst taking it off the bike to remove it, noticed that the axel-chainset interface was cracked....

Game over.

Alright....I mean in fairness....technically, I broke it....but the BB outlasted the chainrings.

cee

ddraver wrote:

+1 for Hope, They do seem to have got this one right!

i'd rather pay 30 RRP for an XT/SLX than the 72 RRP for a hope though.

also if its got a bearing in it....and the words face and race (re-organise into a popular brand)...then avoid.

Anonymous

cee wrote:

i'd rather pay 30 RRP for an XT/SLX than the 72 RRP for a hope though.

Even if the Hope lasts more than 4 times as long?

lostboysaint

yeehaamcgee wrote:

cee wrote:

ddraver wrote:

i'd rather pay 30 RRP for an XT/SLX than the 72 RRP for a hope though.

Even if the Hope lasts more than 4 times as long?

And is infinitely serviceable?

cee

yeehaamcgee wrote:

cee wrote:

ddraver wrote:

i'd rather pay 30 RRP for an XT/SLX than the 72 RRP for a hope though.

Even if the Hope lasts more than 4 times as long?

If it did, then fair enough....

In my experience.....they dont.

folk may very well say that...ahhhh but the hope ones are fully servicable....I reckon the shim ones are at least partially servicable.....at least to clean and regrease.....

its true Hope bearings are easy to replace...havn't tried to do so with the shimano ones...but with stif selling the replacement bearings for 16 quid odds (sure...some of us would get them from a local engineers for less)....that 72 quid goes up to nearly 90.....

Anonymous

Actually, you'll struggle to get replacement bearings for the Hope units. They are a very peculiar size.
Bearings for Shimano BBs are much easier to get hold of.

But still... Hope's ceramic BBs do last a very long time indeed. Every time I thoguht it had reached the end of it's life, it came to be that it was fine, but the pedal bearings, or something else was worn!

cee

yeehaamcgee wrote:

Actually, you'll struggle to get replacement bearings for the Hope units. They are a very peculiar size.
Bearings for Shimano BBs are much easier to get hold of.

But still... Hope's ceramic BBs do last a very long time indeed. Every time I thoguht it had reached the end of it's life, it came to be that it was fine, but the pedal bearings, or something else was worn!

fair enough!

Thewaylander

Will add used to snap the axles off the old taper BB's whilst riding street awful.

external bearing BB's Ive had shimanoe Xt lasted a good year or moe, longer than the old XT tapers i used back int he day, Race face external last about 3 weeks. and now a hope as my bike was under warrenty i had to pay the difference only, so about £30 and that is seeming good after 6-8months

Brig

The BB30 bottom bracket on my 2011 Boardman HT Pro have also gone after 3 rides, total of about 25 miles in dry conditions). Could not ride it anymore as the noise was so loud it turned peoples heads as I came riding...

I don't have any tools for servicing BB30's so I've handed it over to a real bike shop, hopefully they can fix it.

As a comparison the SLX external BB on my DH bike has lasted ages and that's through mud, heavy rain, jumps and drops.

This BB30 rubbish seems to be a massive fail even before it's taken off.

ddraver

yeehaamcgee wrote:

cee wrote:

ddraver wrote:

i'd rather pay 30 RRP for an XT/SLX than the 72 RRP for a hope though.

Even if the Hope lasts more than 4 times as long?

I NEVER said that!!

Anonymous

Sorry, it was cee, your name was thrown in the quote by mistake.

Anonymous

johnsav wrote:

GXP bottom bracket have never failed for me and are cheap as chips

Likewise.

I thought my BB was creaking but turned out it was yet again the pivots (remove, clean, refit, sorted. Never needed to replace anything).

Had also thought the crank felt 'notchy' as in worn bearings kind of feel. Attempted to replace the BB cups but had a big foolish fail on the thread directions and ended up massively overtightening one instead. I knew they go different but just forgot. Now it's not coming off, ever. Still, after all other bits of servicing it's not feeling odd any more, so again it wasn't the BB anyway.

supersonic

It seems a lot of the problems could be caused by incorrect fitting, especially frames not being faced on new builds.