WTF are press fit bottom brackets about?

Just bought a Zesty frame without realising it takes a press fit BB.

Why do these things exist?
What is wrong with threaded BBs?
Is there any benefit whatsoever?
Do they have the same longevity or better than standard HT2?
And finally, will my standard cranks fit?

There is an adapter so you can fit a “standard” BB.

a) no idea
b)nowt
c)possibly not sure but soemone will be along
D) some say yes some say no….pretty standard then for stw
e) what standard cranks…..I had a sram bb fitted and could not fit my shimano cranks so had to buy new bb.

They are cursed….since fitting not been able to ride now 4 weeks and counting……………

There is an adapter so you can fit a “standard” BB.

Tell me more…?

They were invented by someone who hates everyone in the world. Only an evil person could have created them.

There is an adapter so you can fit a “standard” BB.

If they are also press fit doesn’t this just move any issues with creaking to the adapter itself rather than the bearings?

Tell me more…?

The one I’ve seen is two press fit cups that have threads on the inside so you just fit a normal screw in BB.

The adaptor is pressed into the frame like a headset so prob best going to LBS to fit it. After that it straight forward.

I can’t see any benefit ❓

Oh how I wish MTB components were standardized, much money has been wasted buying parts that don’t fit. I keep learning the hard way 🙁

It’s not about what they’re like for you the consumer, it’s about ease of production and fitting, and lower costs for the manufacturer on an assembly line..

They were invented by someone who hates everyone in the world. Only an evil person could have created them.

I think you’re right.

Ok, is it just me? it’s a BB, just fit one and get on with it! it’s not expensive, or difficult to fit?

It’s not about what they’re like for you the consumer, it’s about ease of production and fitting and lower costs for the manufacturer on an assembly line..

Does not putting threads in save that much? Really?

The benefit is that they sit flush with the edges of the BB shell so it can be wider and the whole downtube/BB area stiffer. They are also out of the firing line of the shite.

Apparently…for both reasons

BB30 is annoying as it uses different cranks – though stiffer and lighter? BB90/91 is better as use normal cranks though my experience of BB90 is that you want to re-grease them regularly as water gets in. I reckon BB91 is my preferred version.

Does not putting threads in save that much? Really?

x10.000 for a large manufacturer and it all adds up,

I guess in theory you could have bigger (balls in the) bearings?
and either narrow the Q-factor of the cranks/overall BB width, or make the weld area wider?
I guess they can make it lighter, and charge you more knowing there is less competition for replacement units?

Whether any of the different press fit standards do these in practice I don’t know?

“Does not putting threads in save that much? Really?”
I guess if something does go wrong with the threads/fitting a BB it could be a whole frame/front triangle that they’ve got to bin/recycle
If its press fit, then there might be less to go wrong in manufacture/fitting?

Ok, is it just me? it’s a BB, just fit one and get on with it! it’s not expensive, or difficult to fit?

yes it’s just you; as far as I can see they’re approaching double the cost of an equivalent threaded BB. You also need different tools, which adds to the cost, and if the web is anything to go by, they fail more often.

http://www.chainreactioncycles.com/Mobile/MobileModels.aspx?ModelID=44225

http://www.chainreactioncycles.com/Models.aspx?ModelID=34674

Tell me more…?

This is just the bike industry telling you that they hate you. The real joke is that some people think the bike industry is doing us a favour with this crap.

A guy in my building has a Specialized with one, I think. He gets about 15 minutes worth of riding out of every BB thanks to the weather here in Calderdale. He’s proper p*ssed off and buying a new bike.

I’ve not done any research but this is my understanding;

Cannondale ‘invent’ the BB30 standard, a large diameter bottom bracket shell with cartridge bearings directly pressed into the frame. This creaks terribly after five miles in anything other than a Californian climate.

The ‘solution’ is PF30, which can be fitted into a BB30 frame. In a BB30 the creaking occurs at the cartridge bearing/BB shell interface. With a PF30 the bearings are in a plastic carrier that is in turn interference fitted into the BB shell. This creaks less.

See Wheels Manufacturing for adaptors to fit cranks of your choice. PF30 trumps BB30, but longevity is rubbish.

Fact is BB shells benefit from being a larger diameter than Shimano standards demand – just no-one has engineered a satisfactory light, long lasting, and stiff BB for these large shells. The engineering means must be there, so I vote industry conspiracy. Are cycle industry engineers that rubbish?

Don’t buy Cannondales is a step….they are the worst for problems AFAIK.

Shimano UN-72. Square Taper. Anything since is just buggering about for the sake of it.
FTCA!