Better than ceramic bearings

[Sylv]

Chris King magnetic bottom bracket

[quote]one of the finer advantages of writing thewashingmachinepost is getting hold of stuff before it becomes available to the rest of the world. it's admittedly a rather insular satisfaction, for while few require the signing of a non disclosure agreement, the general understanding is that nothing can/will be said until public release. until then, mum's the word. in the past, colnago have been happy to supply pre-production bicycles for test, publishers regularly send copies of their books several weeks in advance of publication, and it wouldn't be the first time i've received cycle apparel while the catalogue is still being printed.

sometimes, however, the pre-production prototype of a component gives cause for concern; not because of any failing in its construction, or indeed in its daily operation, but with that of personal conscience.

i have long railed against the apparent need to improve certain components on the modern bicycle; most vociferously, the bottom bracket and headset. i have, regretfully, given up on either component being re-formed to its original state; i might be a confirmed luddite, but i know when the ghost needs to be given up. currently i will concentrate on pointing out why cannondale's bb-30 is not a standard, though with my track record, it will likely not be too long before that one bites the dust too.

i've probably given the game away as to my area of review and test, as well as my cause for concern. the chris king cielo i have been riding since the end of 2009 is well kitted out with chris king componentry, namely r45 hubs, no-threadset headset, and a ck bottom bracket. it's this last edifice that rails against my principles. over the three and a bit months of riding, the bicycle has performed impeccably; it is still the closest feeling to gliding one can have without leaving the ground.

but all is not as it seems.

the bottom bracket on the cielo is a chris king prototype that eschews the famed in-house bearings, and replaces them with magnets. so now you can see my problem. for someone who still figures that there was nothing wrong whatsoever with the good old square taper, the thought of the bearings disappearing as well is a bit too much to handle. i daresay, that's progress.

the bottom bracket cups threaded into the steel frame are still manufactured from the same aluminium alloy as regular ck bottom brackets, and thus impervious to the fields of magnetism thrown around their circumference. in a similar principle to that of the maglev railcars, the magnets fitted inside each cup are opposite in magnetic field to those grafted onto the bottom bracket axle, in this case, a sram prototype made for chris king in order to test the principal. i believe shimano are also in on the act.

i have no engineering experience to write home about, but apparently what i do have, according to chris king's marketing chief, chris distefano, is a healthy degree of cynicism. it seems that my constant moaning about bottom brackets has its advantages, however you can be sure that i'm not the only one riding round on a magnetic bottom bracket. according to production manager, jay sycip "while the racing implications are clear, the majority of our bottom bracket sales are to regular riders. it makes sense, therefore, to test it in the real world of day to day."

the method is comfortingly simple: the magnets in the cups repel the magnets fitted at each end of the axle, taking friction out of the equation altogether. fitting the axle through the bottom bracket shell in the cielo was a bizarre experience; initially the cup magnets repel the axle, and it takes an unnerving amount of bravado to give a hefty push on the chainset to slide it past both ends of the bb. once notionally in place, fitting the left crank and bolting it up tight, lines up both sets of magnets, a process aided by some oddly shaped washers and spacers between crank and cup. some of these were factory fitted, but i still had an instruction sheet to make sure i got the other ones in the correct order.

the scary part is that it all works like magic, and there really is no friction at all; leave the chain off to begin with and spin the cranks and they do quite literally go on for ever. assembly was interrupted by the offer of a coffee and a danish from mrs washingmachinepost, and when i returned to the workstand, the darned things were still spinning.

not a particularly demanding rider, i spin rather than grind my way through gears, but so far the magnetic setup hasn't missed a beat. there's no sign of play in the system, something i was convinced would be its downfall, and something i'm required to check at the end of every ride. the magnets employed in the cups are of a similar standard to those used by the aerospace industry, though i dread to think what the cost might be. likely the main selling point would be that the magnets don't wear out. ever.

repeat business might be a problem.

my review and test is designed to last a good few more months yet, accompanied by more filling in of online surveys to keep chris king advised of progress. so far there's no indication of a proposed release date, but i doubt you'll see anything on a ck stand at nahbs for at least a year if not longer, but if it's working this well for everyone else i figure the future is all but guaranteed.

this doesn't in any way undermine my faith in the square taper, but it's very hard not to enjoy that gliding feeling. i suppose i should heed the advice of high-wire practitioners and just don't look down

[Dan_K]

I was so suckered in with this until you posted the 1st April edit!!! (I hadn't bothered going on the blog)

Forwarded it to a couple of people and now i'm the fool

Does beg the question though that if technologies/magnets were light enough and with an adequate power source, would this be possible?

I've got one of those magnetic hovering pens from the science museum and that thing spins like a b@st@rd.

[Sylv]

yes me too for about 5 min
then i asked myself why i wouldn't have read about this anywhere else! and checked the date

[Dan_K]

Guess like all good hoaxes, it's plausible enough to work.

Not like that Di2 electronic shifting, that's a definite April Fool's joke....

[Jon H]

If you could fit an air compressor somewhere on the bike you could have air bearings. Good for 100,000 rpm; should cover most people's cadence.

[sonic909]

[quote="Dan_K"]Not like that Di2 electronic shifting, that's a definite April Fool's joke....

[Phil H]

Di2 is so last year for TTs. The pros have now realised that the Rohloff Speedhub presents a smaller aerodynamic profile than a dérailleur + cassette and can be built as a special close-ratio version. Also the 14 speed twist grip fits neatly onto many aero bars.