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I bought a new carbon frame, which came with a press fit bottom bracket. All of the resources I can find for the installation of these includes information about how to remove the old bottom bracket, but I don't need to do that.

What steps do I need to take, and which tools will I need, to install a press fit bottom bracket in a new frame?

  • There is plenty of information on this subject either on Parktools site or on YouTube. – Carel Apr 18 at 15:21
  • I ended up using a headset press. I put in the drive side first, then the non drive side (which has the sleeve portion). Worked out fine. – Darth Egregious May 1 at 14:36
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Ideally you do it with a press type tool, one cup at a time, with stepped bushings that mate snugly with the cups and the BB shell. For the first cup, one of the bushings is interfaced with the frame to act as a pilot so that the cup stays square and goes in straight, and then for the second cup the other bushing is doing the same while contacting the first cup. This is how the commercial tools tend to work. Making the same thing out of threaded rod and turned or printed bushings is an option if you want a proper tool but don't want to buy one.

Pressfit bottom brackets usually (always?) have a sleeve that bridges the two cups and fits snugly inside a little lip on one or both of them. This makes them more sensitive to going in square during the actual pressing than some other similar pressed-in bike parts. If the second cup gets off-center by much, the sleeve won't mate with it properly as it goes in and can get ruined. For this reason, using traditional home methods for installing pressed parts (blocks of wood and a hammer, vise, threaded rod and washers, etc) can be a little hazardous in the case of pressfit BBs due to the lack of piloting. That's not to say it can't be done.

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I would also add to Nathan’s answer that with it being a carbon frame, if you take it to your local bike shop and they suggest facing the bottom bracket, they may be heading towards messing your frame up. You don’t want to face a carbon shell if it is carbon. It’s probably got a alloy liner so you may be alright.

If there’s no paint on the edge, it needs facing. If not, don’t do it.

Also worth adding some BB press fit lock (thread lock basically) to stop any movement and chance of creaking.

I personally managed to fit mine with some threaded bar and 2 large washers. Went in really easy but I did give it a once-over with a wooden mallet and a block of wood to make sure it was firmly in the shell. It’s easier than you think overall. GMBN even has a simple video on fitting pressfit bb’s.

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    Your second paragraph confuses me. "if there's no paint on the edge of the BB housing, then it should be faced." makes sense. "if not, don't do it" <-- that bit seems to disagree. Could you please clarify ? – Criggie Apr 18 at 21:05
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    If your bb shell is just carbon which is quite unlikely, you want to be extremely careful about choosing whether to have it faced or not. I would say it’s a decision you need to talk through with a good bike shop. For many carbon frames though, you’ll have an alloy shell or liner. This can be faced if needed. You can normally see only bare metal on the edge because it’s already been faced. If it’s painted, you may need it facing to be sure it’s perfectly true. I’ve never needed to face mine but I’ve not been through a huge number of bikes. – Chris Apr 19 at 22:25
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Alternatively, you can purchase an adapter to allow you to use non-pressfit cranksets with 24 mm spindles such as Shimano Hollowtech II, designed for ISO/English-style bottom brackets. They're manufactured by KCNC, Wheels Mfg, Praxis, Race Face, and probably quite a few more. I think Praxis even makes one that can be used with cranksets that have 30 mm spindles that were designed for PF30/BB30 bottom brackets. The adapters screw together inside the frame, maintaining tightness and alignment. They use standard ISO/English-style outboard bearings, so if you have one of the newer, wider press-fit bottom brackets on your frame (BB86/BB92, IIRC) they're probably not available.

Along with being a lot easier to install (and remove!), you'll be a lot less likely to wind up dealing with the creaking and cracking noises that are standard features of press-fit bottom brackets.

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