Chainring Countdown

Question: So the dirt world gave up on the five-bolt crank a while ago for no apparent reason. Now FSA is running ads for a three-bolt crank. Where will it end: a no-bolt crank held on by good intentions? What’s to be gained by the different bolt patterns anyway, aside from orphaning whole warehouses of perfectly good chainrings?

Approved Answer: The key here is something called “system engineering,” which refers to the habit component manufacturers now have of making all their stuff only work with their other stuff. Back when mountain bikes as a concept were a dark and terrifying forest of confusion, brands tended to make wild guesses about what might work best, usually by putting photographs of motocross and road bikes on the wall next to one another and opening and closing each eye real fast until the two sort of blurred. But at least manufacturers all stuck together on those decisions. Hence you had brake levers modeled closely after the lever on a Yamaha YZ 125, and mighty “standard drive” 5-bolt chainrings with at least 46 teeth. These were different times.

I’m pretty sure Shimano fired the first shots in the proprietary chainring revolution, but, like any slow descent into a corporate state, it was the willingness of the people to go along with the change that really allowed it. Your friend who had to have the Coda crankset with the built-in alloy chainrings? He did it. We all let chainring standards disappear because it was the ’90s, and we were all about buying a whole new crankset when our rings wore out; and because we really liked lightweight stuff.

Manufacturers started shaving away everything that wasn’t necessary, and it became apparent that designing your components to work with a countless array of alternate parts available from other brands made less and less economic sense. That’s why today we have only the stammering zombie remains of the last known chainring standard, the 64mm/104mm 4-bolt ring.

The Real Answer: For the past ten years, decisions about standards and innovations in the bike industry have been tightly controlled by a single overseer. The symbols and letter-like-slashes “Mittens” scratches daily into the leg of a dining room table in a home somewhere in Bayonne, New Jersey are taken as infallible engineering law, transcribed, and sent directly to Taiwan and China for the fabrication of new bike parts. This is the real source of most designs you see currently on the market.