There’s no small amount of irony in the fact that the best solutions for creaky press-fit bottom brackets all incorporate cups that thread together to lock everything in place. We’ve been impressed by designs from Enduro, Praxis, Wheels Manufacturing, and others, but Taiwanese company Legit Engineering might just have the ultimate magic potion for keeping things silent, once and for all.
Like the Enduro TorqTite and other similar designs, Legit Engineering’s Twist-Fit bottom bracket features aluminium bearing cups that thread together in the center, tightly sandwiching the frame in between the flanges to prevent movement. Where Twist-Fit differs, however, is in the clever Snug-Ring: a thin layer of glass fibre-reinforced polyamide composite that surrounds each cup where it’s pressed into the frame.
Legit engineering’s twist-fit press-fit bottom brackets use thread-together aluminum cups along with thin composite liners that insulate the cups from the shell:
Legit Engineering’s Twist-Fit bottom brackets for press-fit frames use thread-together cups plus a fibre-reinforced plastic ring to keep everything from moving
That composite ring – supposedly the same material as what Shimano uses for its press-fit bottom brackets – essentially provides a buffer layer in between the aluminium bearing cup and frame, much in the way that grease can silence a noisy threaded setup. That slightly softer composite material can also correct for minor imperfections in shell diameter and shape but without affecting bearing preload like all-plastic cups often do. To endure a precise fit, each ring is actually CNC-machined after they’re molded – a far more expensive process than if they were just slapped on straight out of the molding machine.
Legit Engineering offers the Twist-Fit design in twelve different variations to fit nearly any combination of commonly used press-fit shell and crankset spindle. There’s also a dedicated complete tool kit to install and remove the cups without damaging either the bearings or frame.
While most companies would be content to just injection molded parts and call it good, legit engineering takes the extra step of cnc-machining the composite cup liners so as to get a perfect fit – a critical step for eliminating creaks:
Legit Engineering says one of the secrets to the Twist-Fit design is how the fibre-reinforced plastic insulating rings are machined after molding for a precise fit
Unfortunately, actually getting one of these bottom brackets might not be very straightforward. Legit Engineering is currently seeking a US distributor and has apparently been selling Twist-Fit in Asia and select European countries for a couple of years but there’s no web site that we could find, and the one provided to us here at Sea Otter doesn’t work.
We’ve got a PF30-to-24mm conversion bottom bracket on hand, however, and it looks highly promising. We’re almost hoping it doesn’t work, though, because it’d almost be worse to have finally discovered a foolproof solution that no one can actually buy. Stay tuned.