Everyone hates press-fit bottom brackets, right? Here at Bike, we've been complaining about them for an entire decade now--and for the most part they've deserved it. Things were pretty bad for a while. As a professional mechanic, I've spent hundreds of hours chasing press fit problems. I've researched and bought expensive adhesives, sleeve retaining compounds and curing agents, not just to keep the dumb things quiet, but to actually keep bearings in frames. It's a real thing that happened, and sadly, it was pretty commonplace for bottom brackets to literally uninstall themselves during use--a problem that was solved nearly a century ago by using left hand threads on drive-side cups.
So why on earth do companies continue to produce bikes with non-threaded bottom brackets? Because, carbon. You can't cut 24tpi threads into the type of carbon that frames are made out of, so putting a threaded bottom bracket shell onto a carbon frame requires glueing a large aluminum part into the frame--which requires two different materials to be bonded--which isn't ideal. It's heavier, more difficult and expensive to manufacture, but more importantly, it's not totally reliable. It isn't unheard of for those bonds to come loose, permanently separating you from that particular frame. Engineers can create better carbon bike frames if they don't need to design around big aluminum parts being bonded into high-stress areas. It's sort of like the only analog thing left in a digital world. That's why press-fit hasn't gone away--it's actually why it shouldn't. Think about it this way: without threadless headsets there'd be no carbon steerer tubes. It's called progress.
The problem with press-fit isn't that it's not threaded, it's that it was implemented horribly from the start. That's finally changing. Even the plastic stuff made by Shimano and SRAM is getting better, but I think the thread-together style bottom brackets offer by far the best solution right now. Below are a couple of my favorites, from Hope and Wheels Manufacturing, both with BB92 (a.k.a. PF41 and PF92) frame fitment and SRAM GXP cranks.
Both bottom brackets thread together inside the bottom bracket shell to provide a quiet, long-lasting and durable interface between frame and crank, but they're designed much differently. Which one is better? Keep reading to find out.
Wheels Manufacturing Thread Together Angular Contact Bottom Bracket
BB only $100
Installation Tool: $14 – $50
The Wheels Manufacturing thread together bottom bracket is the simpler of the two, consisting of a couple aluminum parts with a familiar 16-notch tool interface, a pair of seals, and some spindle spacers. While the two sides do thread together, you'll still need to start by pressing the drive side cup into the frame. The big bummer for home mechanics about all press-fit bottom brackets is the need for a bearing press and the correct drifts, however Wheels Manufacturing sells a universal bottom bracket press for $30, so it's not a huge investment for the do-it-yourselfer.
After pressing the right-side cup in, you just thread the left side on and tighten to 35-50Nm. It's simple as pie, although, if you want to do it yourself, you will need to pick up a tool for that, too. Even though it looks like your standard Hollowtech II interface, it's actually a couple millimeters larger in diameter (48.5mm). The good news, though, is it's not proprietary. It's a relatively new tool interface standard, but at least other people are using it, so your local shop is more likely to have the correct tool to install it.
I wouldn't recommend the $14 dollar Wheels Manufacturing spanner-style tool to any serious mechanic. You can't get a full rotation of the tool without hitting the frame, so the tool constantly has to be repositioned. It's also quite thin, as are the notches on the bottom bracket itself, so it's really easy to slip the tool and bugger the aluminum cup.
Most of the socket-style alternatives also miss the mark. Abbey and Park make tools that will fit the notches, but they each have a center guide to keep them straight on the narrow tool interface, which fits into a BB30 bearing, not the 22-millimeter one found on the GXP-fitted bottom bracket. FSA's MegaEvo socket tool looks okay, but it's $60, it uses a 1/2-inch ratchet size instead of 3/8, and its slightly round-edged cast steel construction wasn’t built with this bottom bracket’s shallow shoulders in mind. What I really want is a machined, sharp-edged, perfectly flat aluminum socket. And just as I was finishing this review I got news Wheels Manufacturing has manufactured exactly that. It’s not cheap at $50, it also uses a 1/2-inch socket, but it comes with a 3/8 adaptor, and it’s just what I wanted.
All installation and tool talk aside, the Wheels Manufacturing thread together bottom bracket works flawlessly. This one has angular contact bearings, but Wheels also sells one with normal radial ones too. I opted for angular contact because, as long as they're installed with the correct amount of preload, they should be smoother and longer lasting than radial bearings. When the bearing is preloaded, every ball is engaged with the race, whereas with a radial bearing only a few are at a time. This distributes the load more evenly, which should improve the bearing's lifespan. The trouble with angular contact bearings is, if they're under or over tightened, you can wreck them very quickly--like in a single ride.
My SRAM XX1 cranks installed with the perfect amount of preload without needing any of the provided spindle spacers, and they definitely spin more freely than the Hope setup does. The difference is totally negligible of course, but it sure does feel nice. After a fair amount of wet Pacific Northwest miles, the bottom bracket is still running as smoothly as the day I installed it, and it hasn't made a peep.
The aluminum cups are basically non-wearing parts, so as long as you don't completely mar the tool splines, the cups should last forever. Wheels Manufacturing specs high-quality, Enduro-brand bearings, which can be replaced when needed.
If I'm being super picky, I'd have to admit I prefer the cleaner look of the Hope bottom bracket, which doesn’t have any tool interface notches for crap to build up in. I also don't love that installing the left cup of the Wheels bottom bracket requires the cup to rotate in the shell, which means forcing it through a lot of friction, and could cause marring. This didn't happen on my frame, but I can't guarantee it's a non-issue altogether. The best way to ensure a smooth installation is to make sure the surfaces are smooth, burr-free, and properly lubricated with Teflon grease (or anti-seize for titanium frames). As far as performance, though, I have zero complaints.
Hope Tech Press Fit 41 Bottom Bracket
BB only: $140
GXP Conversion Kit: $14
Installation Tool: $50-75 online
Even though it required six steps to install, compared to Wheels Manufacturing's two steps, I actually prefer the Hope's fitment. There's no tool interface to mar up and make ugly, which goes a long way for me. I'm OCD like that. More than that, though, I like that both sides press in, rather than one side turning in the frame like the Wheels bottom bracket. The downside--which could be a total deal breaker for a lot of folks--is that you need Hope's proprietary tool to install this sucker. Unless your local shop has decided to spec Hope bottom brackets, they're not very likely to have one, which means you're likely footing the tool bill.
The Hope bottom bracket is more of a kit that needs assembly, rather than a simple bottom bracket. But once installed, it's totally bombproof. It basically consists of two aluminum cups that press into the frame and house the bearings, connected to each other via a thread-in sleeve.
Installation goes like this:
1) Press in the drive-side cup
2) Press in the non-drive cup
3) Thread in the center tube
4) Install inside GXP adapter spacer in non-drive bearing (GXP only)
5) Press non-drive bearing into cup
6) Press on outer GXP adapter spacer and dust seal in non-drive bearing
Only then can you install the crank. It's a bit of a process that takes a little time and requires care. A friend of mine bought the bottom bracket and tool, per my suggestion, and somehow managed to destroy the tool--and almost the bottom bracket and frame--in the process. The whole thing seems pretty dummy-proof to me, especially after watching Hope's ASMR-inducing installation video--but it wasn't Mike-proof. That said, he did finally wind up getting the thing installed, and has since stacked many bull-in-china-shop-style miles. Mike's riding and wrenching are done in a similar fashion.
Hope supplies its own high-quality sealed radial bearings that have proven to be very durable. Replacements can come from Hope or anyone else you like. You could even convert to angular contact bearings, which is what I'll likely do once the stock bearings wear out. The aluminum cups and center tube will no doubt last longer than the bottom bracket standard they're built for, so any further investment is simply the cost of bearings.
I have a similar number of miles on the Hope and Wheels Manufacturing bottom brackets, and the Hope is starting to feel slightly gritty while the Wheels unit is still running perfectly smooth. The difference can only be noticed when spinning the cranks by hand with the chain off. From a practical standpoint, it's inconsequential at this point. There's no way anyone would feel it when riding, but it could be a signal that the Hope bearings are wearing faster.
Nonetheless, it remains quiet and trouble-free. I'll wait until the bearings get super grindy, or develop free-play before I touch it.
Removing the Hope bottom bracket is more involved than taking the Wheels Manufacturing ones out. With the Wheels, you can just unthread the non-drive side, and while there are still a couple threads engaged, you can then tap the non-drive cup with a mallet to knock the drive-side cup out. Removing the Hope requires pulling the non-drive bearing, then the sleeve, and then tapping the cups out with a non-marring drift (I use an oak dowel). The bearings on either bottom bracket can be replaced without needing to remove the cups, but they'll last long enough to install in your next bike too, if it has the same diameter bottom bracket shell, that is.
Choosing a winner is tough for me, because I prefer the fitment of the Hope, but like the angular contact option offered by the Wheels. I think if I weren't a mechanic, I'd go to a shop and have them install the Wheels bottom bracket and I'd forget about it. But the precision and finish quality of the Hope is impossible for me to ignore. Plus the tool is really well made, which makes my toolbox happy.