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ive never stripped a thread on a bottom bracket but i suppose thats the only potential gain from press fits
or just another ill thought out industry standard?
At least you can use 'normal' size HT2 type cranks in them, ie just the bb that's different no the whole crank system. (Oh no, someone's changing all that too aren't they? 🙄 )
I suppose it gives the frame builder more options with regard to the shape of the seat/down tube and chauinstay junction: if you need it wider you aren't limited to 73mm or forced into using 'special' wider cranks.
easier for manufacturing, possibly lighter.
More complex for home [s]mechanic[/s] bodger.
Think I'll be avoiding.
Nothing their gash!! Another road bike design filtering into mtb's. I think the guff is that its a wider bb shell so makes it stiffer, but also means its more of a pain in the arse to change over your bb and that means more new tools and you can't run a bb mounted chain device or add bling to your bike with nicely coloured external bb's. Utter crap imo whats wrong with external or square taper.... nothing.
Mainly it allows bike manufacturers to use a bigger, wider tube for the BB shell, so they can make a stiffer frame.
Frame builders can make that 'pivot' area stronger as the BB is wider and therefore the connecting tubes onto it can be bigger.
Main reasons - no threads to screw up (either in manufacture, or later when the seize/crossthread/wrong threading) and lighter weight. Are those benefits worth the hassle, multiple standards (BB86, BB90, BB92, BB30?), additional tools required, etc? That's up for debate.
EDIT: @100mphplus - I think that's one of the claims touted for push-fit, but that could be achieved with threaded bottom brackets (threaded bearings/races as opposed to push fit) too.
Well no-one can see the massivley expensive lovely anodised chi chi bottom bracket you're running, that's a black mark right there.Utter crap imo whats wrong with external or square taper.... nothing
Main reasons - no threads to screw up (either in manufacture, or later when the seize/crossthread/wrong threading) and lighter weight. Are those benefits worth the hassle
Yes, because there's no possible problem with me hammering a set of bearings in at a dodgy angle into my expensive carbon frame thus ruining it.
Basically it's quicker for manufacturers to build bikes therefore they make them cheaper. Then they make up some hype that it's better for the punter.
Plus component manufacturers get to sell more BBs because they seize up even quicker than Race Face extrenal BBs used to?
Ain't the bearings bigger?
Epic fail if not.
Surely you could design a bike with whatever bearing size you chose as long as the axle dimensions fit the standard you could press soem huge bearings directly into the frame couldn't you?
[i]Yes, because there's no possible problem with me hammering a set of bearings in at a dodgy angle into my expensive carbon frame thus ruining it[/i]
The same arguement could be made of headsets.
Only positives I can see are at the manufacturing stage. No handed cups means you don't have think about sides and thread directions and they must be quicker, hence cheaper to fit. You just grab a pair of cups and bosh them in.
After that they are just terrible things with poor longevity and they're really difficult to remove without destroying them, even with the proper tools.
Awful things.
The same arguement could be made of headsets.
I'm sure I've suggested on STW before that headsets should be fitted like external BBs.
Unfortuantely no bike companies seemed to spot it and so it has not yet become the new "standard".
🙁
Utter crap imo whats wrong with external or square taper.... nothing
Give me a square taper and I'll round it off for you, free of charge.
I appreciate that innovations in b/bs may improve stiffness, but is it actually of benefit in the real world? I've changed a few square taper/ octalink systems over to external b/b, and I can't say I've ever noticed a difference. What I have noticed is the massively reduced bearing life.
Various bikes have had their own press-fit "std" previously - see Fat Chance. They worked fine.
chakaping - Member
The same arguement could be made of headsets.
I'm sure I've suggested on STW before that headsets should be fitted like external BBs.Unfortuantely no bike companies seemed to spot it and so it has not yet become the new "standard".
This is a joke yes? Please?
What would the benefits be?