BB386 Press Fit bottom bracket

[SkipdiverJohn]

Although given his love of older bikes, I'm surprised he even knew Presfit B/B existed.

I'm well aware of the trends and developments in modern bike design. The reason I don't embrace any of it is I think it is 99.9% pure marketing-driven rubbish and not any sort of tangible real-world improvement. I do like and use LED rechargeable lights and highly puncture resistant tyres though, but all the dross like 1 x "gravel" drivetrains, PF BB's, through axles, threadless steerers, sealed wheel bearings, disc brakes, aero wheels, aero frames, special supposedly vibration damping carbon fibre layups, and non-interchangeable proprietary parts are just designed to part the gullible from their cash.

 

[ianrauk]

https://www.hambini.com/pressfit-vs-threaded-bottom-brackets/
NB Volume down to start with.
What do you mean by 'upgraded'?

Cheers for this. Very watchable, (and should I say... entertaining.), I've watched a couple of his vids and learnt a lot.

 

[weareHKR]

I'm well aware of the trends and developments in modern bike design. The reason I don't embrace any of it is I think it is 99.9% pure marketing-driven rubbish and not any sort of tangible real-world improvement. I do like and use LED rechargeable lights and highly puncture resistant tyres though, but all the dross like 1 x "gravel" drivetrains, PF BB's, through axles, threadless steerers, sealed wheel bearings, disc brakes, aero wheels, aero frames, special supposedly vibration damping carbon fibre layups, and non-interchangeable proprietary parts are just designed to part the gullible from their cash.

I take it you're still riding around on a Hobby Horse?

 

[SkipdiverJohn]

I take it you're still riding around on a Hobby Horse?

I find pedals more efficient personally, but on a serious level there have not been any significant real improvements in everyday bike design for at least 30 years. There's been loads of hype, loads of crap engineering, and loads of parts that will only fit one model so the maker can force its obsolescence but all said and done something from the 80's or early 90's is just as useable as anything made now, and most importantly can be kept going well into the future when most of the modern stuff will have long since been turned into landfill. When you run bikes comprised of industry standard common mechanical parts, you own the lifespan of those machines. If you buy ones embodying proprietary parts, the manufacturer does. I'm not interested in marketing-driven tech of no tangible value to me personally.

 

[faster]

Not really - even Shimano's Hollowtech system when using a threaded BB uses a bearing pressed into the plastic cups. Just because the interface to the frame is better doesn't mean the bearings are held in differently.

No they are not! The bearings in Hollowtech threaded BB's are pressed into aluminium cups, and very nicely machined ones at that. It's extremely rare for these to creak.

The exception being square taper type BBs such as BB-UN series from Shimano - but sadly they are not used on most bikes.

Much more likely to creak in my experience and clearly an inferior design. They do go on and on though, I'll admit that.

 

[si_c]

No they are not! The bearings in Hollowtech threaded BB's are pressed into aluminium cups, and very nicely machined ones at that. It's extremely rare for these to creak.

So they're press fit then 👍

The bearing interface is pressed into the shells, that they are then screwed into the BB is largely irrelevant. The difference between it and PF30 for example is the manufacturing tolerances achieved. This is why it is less prone to creaking.

Square taper creaking is usually a sign the cranks aren't on tightly enough in my admittedly limited experience.

 

[SkipdiverJohn]

Cup & cone threaded BB's don't tend to creak at all. If the bearings are badly neglected they just rumble or even click if one or more balls has disintegrated. As mentioned, loose crank arms are the common problem, and easily dealt with.

 

[Tripster]

So glad my next bike is a threaded BB

 

[Ajax Bay]

@si_c I think it's useful to discriminate between the ways a bottom bracket fits into a bicycle frame. There are 2 engineering solutions: either a BB is pressed in (press fit) or it's screwed in (threaded). Other than cup and cone, if we adopted your nomenclature all other BB bearings would be termed 'press fit' whether the interface with the BB shell was threaded or a friction fit. I don't think this would be useful and generally would serve to obfuscate. But if you think it worth it, do enjoy the intellectual 'Man of Hoy' (high ground).

 

[faster]

So they're press fit then 👍

No, they're not.

I can't make out whether you are just playing about with semantics in order to be deliberately obtuse, or genuinely don't understand, but for the benefit of doubt, for press fit systems, the end user has to press the bearing assemblies into the frame. In other systems, the end user doesn't - usually they are screwed into place.

In your definition, square taper cartridges would also be press fit. How do you think they get the bearings into the cartridges?

The bearing interface is pressed into the shells, that they are then screwed into the BB is largely irrelevant.

The difference is that with Hollowtech, the potentially troublesome press fit interface is changed along with the bearings for peanuts. With pressfit, in order to change the outer housing (expensive and elaborate engineering solutions accepted), you need to change the whole frame.

I'd say that is relevant, and I think most would agree with me.

 

[DRM]

As Hambini points out on some frames with hollow tech bb’s they can still be rubbish if, as in some cases the bb shell is made of 2 separate halves that are then misaligned, I personally think there’s nothing wrong with pressfit, so long as the hole that the bb is pressed into is A, aligned correctly, B, is the correct dimensions, C, isn’t oval, manufacturers really ought to use a section of tube of the correct dimensions to build the bb part of the frame around, the slight weight penalty would be worth it’s weight in gold to have a problem free bb, it’s really down to bare minimum build cost, and maximum selling price to the end user, if Look can manage it, then so can everyone else

 

[Cycleops]

And therein lies the problem @DRM , the name on the frame isn’t always the manufacturer, the frames are contracted out to various fabrication companies. The manufacturers have to rely on the fabricators getting it right with good QC but I imagine standards slip and then you get the problems.

 

[DRM]

And therein lies the problem @DRM , the name on the frame isn’t always the manufacturer, the frames are contracted out to various fabrication companies. The manufacturers have to rely on the fabricators getting it right with good QC but I imagine standards slip and then you get the problems.

There’s really only a couple of big frame manufacturers, Giant being the biggest, yet my Carbon Defy complete with pressfit bb has being exemplary despite being four years old, is as quiet as a church mouse