Press in BBs are hot, but are they worth it?
Most readers of this blog know about the many new types of BBs used today. We offer virtually every type of BB used today in ceramic versions. We do this because the industry has changed from one of very simple BB styles, to one where almost every frame maker has to design their own BB style, just to compete and market their new frame. We are happy to offer all of these different styles as we try to offer want our customers want. But if we had our way, it would be different....
So let's first look back at how it used to be. It used to be that most frames came with an English threaded BB shell. Exotic Italian frames used an Italian threaded BB shell. Either way was fine as all you had to do was buy the appropriately threaded BB that matched your crank. These older BBs used smaller bearings that were housed inside the frame (for better durability) and smaller spindles. In theory, the smaller bearings weren't as durable and able to withstand load, compared to today's bearings, but in practice this was never really true. You hear stories of old Campy or Shimano BBs lasting 10 years, even 15 years with no maintenance.
Then one day the bike makers said, "hey we can design our own BB style and market it explaining why it is better". First the industry went to outboard bearings, which were larger and stronger. This was a nice progression for BBs, while they did have more drag, the larger bearings were stronger and offered better longevity. Then they went further and said "let's do away with the cups all together and press the bearings directly into the frame!!"
Sounds great but sometimes a step forward might not be truly forward in all aspects. For this article, we'll focus on the two most popular press-in BBs, BB30 and BB90 There are many more, but these two are the most popular (plus BB30 has quite a few siblings). First BB30- large bearings pressed right into your frame. Then BB90- smaller than BB30 but still large bearings, pressed right into the frame. In a perfect world they would be great. But we live in an imperfect world where manufacturer tolerances vary and a press fit bearing that needs an exact fit in order to not creak and click and drive the rider insane, makes said idea not great.
The common complaint with BB30 and BB90 is that they click and creak. This is almost always due to the bearing moving ever so slightly under load because it is not pressed into a perfectly matched space. The tolerance varies on frames, even high end frames, and this is bad for bearings. So the industry tried to fix this by offering Press Fit BB30 and BB86. These are basically the same as BB30 and BB90 (forgetting for a moment that BB90 only appears on Trek frames) but rather than pressing the bearing directly into the frame, the bearing is housed in a plastic cup and then pressed into the frame. This allows the plastic cup to take up any tolerance issues with the frame. It could have fixed the issues, but still you hear reports of clicks and creaks because the tolerance in the frames is still not good enough and now the plastic cup moves slightly.
When you pedal your bike, everything is transmitted to the BB. So any possible way the BB can dissipate that force, it will. So if something can flex or move, it will and this will cause you creaks and clicks.
How do you go back to the old days? You don't, unfortunately. The pros will always want the best parts, and they should. They don't care about noises because they view their bikes as tools more than we do. We view our bikes as friends, partners, an extension of ourselves, so that we can enjoy the world at a slower speed than allowed by cars. We like our bikes to be quiet so that while we are riding them, enjoying the world around us, we don't have to listen to them. The pros don't care as much as they are going from point A to point B as fast as possible. If they have an annoying click, they mention it to their mechanic at the end of the race and let him deal with it.
So, how do we deal with press in BBs and their inherent flaws? Trial and error. Fixes can include obscene amounts of grease, Loctite, proper torque and lots of patience. These new BB types are superior technological wise, but at the same time suffer from some drawbacks. But don't fret, anything that creaks can be fixed, you just have to identify the source and decide how to fix it.