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These have a tapered spindle with a 30mm drive side bearing and a 28mm left side bearing. Praxis sells chainsets with its own M30 standard. And you need either a 24mm diameter or BB386Evo chainset (which FSA would be pleased to sell you). Although the bearings are placed further apart than in a BB30 set-up, the downside is that the axle is longer than a BB30 axle and so is a bit less stiff. The bottom bracket shell width is 87mm, while the 46mm shell diameter means that it will accept PF30 bearings. But the BB86 bearings are totally enclosed within the bottom bracket shell, so there’s even more bottom bracket real estate, allowing designers to beef up the bike’s down tube and chainstays. This places the bearings 86mm apart – the same distance as its screw-in external bearings.
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Shimano’s preferred press-in bearing solution is BB86. Which is why you’ll often see bikes sold with FSA chainsets in BB30 bearings, but otherwise using Shimano mechanicals. But Shimano has never joined the BB30 party, preferring to promote its own press-in bearing standard. This is essentially the same as BB30, but just moves the left hand bearing outwards by another 5mm, adding a bit of extra crank stability.Ĭampagnolo and SRAM offer BB30 cranksets, as do FSA and other groupset makers. So Cannondale is increasingly using BB30a bearings on its more recent bikes. Early BB30 frames were notorious for creaky bearings, although Loctite and more accurate frame building have reduced the problem significantly.Īlthough the BB30 and PF30 standards have been widely adopted, there’s still a little distance between the crank arm and the bearing on the non-drive side. But the BB30 standard requires close tolerances in the frame to ensure that the bearings fit without play. Pressfit bearings are widely used for modern carbon frames. Having the bearings inboard in the shell means that there’s extra room for wider frame tubes, allowing bike designers to add frame rigidity for more efficient pedalling. The axle diameter is increased from 24mm to 30mm too, which means that it can be made lighter without losing rigidity, although the shell width is still 68mm. There’s a circlip inside the shell on either side to ensure that the bearings stay in the right position. Rather than screwing in, the bearings are pushed into the carbon bottom bracket shell, using a threaded press, like that used for headset bearings, and a special adapter to fit the bearings and make sure that they end up parallel. So Cannondale promoted its BB30 system as an open solution which could be adopted by other manufacturers.