I recently had a dilemma: I really wanted to buy a new frame and the one that I had set my eyes on was the Viner Maxima RS 4.0, that for me and my budget looked perfect… except for one detail: it was designed to accept a PF30 (PressFit 30) bottom bracket which for me was a problem.
Squeaky PF BBs & Shimano Hollowtech Cranks – Not only had I heard and read all about the “fact” that “all” press fit bottom brackets (BBs) eventually squeak, but the standard PF30 BBs accept cranks with a 30mm spindle. However as I already own Shimano Dura-Ace cranks with a Stages power meter fixed to them the issue was these Shimano Hollowtech cranks have a spindle diameter of 24mm and I really did not want to get myself some new cranks, nor could not afford to, as it would also mean having to lose my power meter or get a new one in the process. #notgoingtohappen!
Now I may not be the most technically gifted person on the planet, but I am also no mug either, but when I first looked into what my options were, I got into a complete mess. With all the “standard” widths and diameters available on BB’s it almost drove me over the edge! Anyway I persevered and as far as I could see it below were the choices that I had that would allow me to install my Shimano cranks onto my frame designed to take a PF30 BB:
1) Reducer Cups
These simple reducer cups allow the installation of a Shimano crankset onto a PF30 bottom bracket. So first you install a pressfit BB on the frame, then you add these reducer cups to it so that the thinner 24mm spindle will go through it.
The advantage of these is that they are cheap, but it would still require me to buy a PF30 BB as well and I felt that there was now even more chance that my BB would squeak because of the added complexity etc. It also to me just looked a little like a bodge type of solution and so I quickly eliminated this solution as a viable option.
2) PressFit 30 to BSA Adapter Shell
Next on my researched list of options and which is the solution that Planet X use when they build up their PF30 frames like the Viner with Shimaon components is to use an Adapter shell.
Here you basically press fit an adapter shell into the frame. This shell will then accept a “normal” threaded style bottom bracket. The advantage of this is for me was that it is a cheap solution because I could use the brand new Shimano Hollowtech 2 bottom bracket that I already had as a spare.
There are a number available, but from research, it seemed to me that one of the best is made by Sram and can be found for around £10 – 15: Sram PressFit 30 to BSA Adapter Shell.
However, as tempting as it was, I eventually decided against this option as I was once again worried about squeaking and in a bid to remedy this, many people glue the shell into the frame, making it’s removal either very difficult, or in some cases impossible.
3) Specially Designed Bottom Brackets
Last option for me was to opt for a specially designed bottom bracket that would fit into the PF30 shell on the frame, but which accepts the 24mm spindles on my Shimano cranks.
Here I soon narrowed it down to two options, the very highly rated Praxis Works conversion BB or the KCNC PF30 adaptor bottom bracket.
Both are similar, although the Praxis one has a rather ingenious shell that expands as you screw it together that they say reduces the chance of your BB making any noise.
However it is also a fraction heavier and more expensive than the KCNC version that I eventually settled on – cost me €29,99 (£25) at alltricks.
This problem is way more complicated than it should be!
So I have tried to write this article in such a way as to make the choices available as easy to understand and straightforward as possible, so hopefully if like me you are having a problem getting your head around it all, it helps.
As for the right choice, I think it depends on a number of factors and your budget and I don’t think there is not really a wrong choice here.
In time , I will be writing a full review that will include my experience of installing and then using the KCNC PF30 bottom bracket. Until then, I would love to know what you guys have used and your experiences with your solutions.