Are they as bad as their reputation would indicate?
I'm thinking about building a bike using a Chinese carbon frame and one of the options has a press fit BB.
Nope. They work a treat. My 15 year old Cube road bike had its first "new" BB last year. Occam has had two from new - and that's about 8 years old now. Fatbike gets the worst abuse due to the sort of conditions I ride it in and that's on its second in 7 years or so (and the first was a RaceFace!)
A cheap press and a mini "rocket tool" makes for simple replacement.
No issues with the press fit on my Aithein - but I do use Loctite 641 when installing new cups.
But if I had a choice I'd go for a threaded bb every time (the second generation Aithein's use a threaded bb...)
ime absolutely fine, ive had 3 bikes with them and never had any bother, when it came time to replace them (i swapped for a wheels mfring one twice and only had to do one bearing change on the latest one)
As with many things, you only hear about them when they go wrong. How many unsolicited reviews have you seen along the lines of "my BB has not squeaked or done anything at all unusual, TBH I never really think about it at all. 5 stars."?
I've had one (Shimano XT SM-BB800-PA) for 4 years on my mtb. Faultless. Fitted it myself with one of these: https://www.ebay.co.uk/itm/282534841022
They're as good as their screw in equivalent in my experience, cheap ones don't last as long as expensive ones.
I've had bikes with them for at least 8 years and they do their job nicely.
In my experience shimano press fit bbs last longer than shimano threaded.
I've had three bikes with press fit BBs - no problems with any of them.
Had two bikes with press fit BBs. The one on my Trance creaked like a creaky thing but the one on my Revolt Advanced never made a sound.
Replaced the Trance BB with a Wheels Mfg screw together jobbie and it has been faultless. When the Revolt BB needed changing I replaced that with a screw together as well. Not having to remove the BB to change the bearings makes it worthwhile IMO.
Got a PF41 BB on my Warbird - fitted a Hope screw-together one from the off, and its been fine.
As with everything, it depends.
The FSA PF30 on my spearfish lasted one wet 4 hour race while in the 2016 the fella that came second in the TD rode an On-One kurcher SS with no hassles.
Aside from the FSA above I've never found them to be a problem and at least the tools are consistent to fit them, not like thread in ones.
Press fit bb with 30mm spindle was absolutely useless in my experience, lucky to get a few months use before bearings seized. A mate has a Giant reign and his 24mm shimano bb is still going after almost 6 years, although he doesn't ride much in bad conditions
No thanks. Giant and Specialized have moved back to threaded, and they didn't do it for the goodness of their health. In my experience Shimano bearings last longer than the tightness of fitting into the shells (Defy Sl and Propel SL bearing fine, creaking not fine). And I'll never own another Cannondale BB30 frame. Ever.
There are some combinations of press-fit BB + crank best avoided like PF41/30mm spindle as the bearings are tiny. Another issue is where you have bearings pressed directly into the shell, dirty water gets down the seat tube and the bearings are effectively sitting in water - drilling a hole in the BB shell is a wise move. I’ve got a couple of press-fit BB bikes - I designed the frames for them as they have wider chainstay clearance and they’ve both been faultless. Screw-together BBs like Wheels Manufacturing help resolves issues like poor sealing and bearing alignment.
Followed a guy up Holme Moss on a Cervelo that sounded like his BB / axle would have worn though the BB shell by the time he was at the top. Worse than bag of spanners being rubbed on a cheese grater.
I have stayed clear since then. Except for the eccentric BB on the Shand, everything else is threaded in my stable! As earlier, there's a good reason Specialized has moved back to threaded on many of their bikes.
My Spark has a PF - creaked when I first got it but my ‘Bike Man’ sorted it and it’s been fine since and that was a good few years ago.