Full Speed Ahead has put the finishing touches on their modular crankarm, chainring and spindle system with the new Gradient alloy and MTB PowerBox Carbon 2x cranksets. Now, their lineup offers options across the price range, letting you mix and match to fit your bike and your budget. Or easily move your high end carbon cranks to a new ride, whether it’s a road, gravel, cyclocross or mountain bike.
While a 2x option was shown when FSA first announced their partnership with Power2Max to create the PowerBox power meter cranksets, it hadn’t been available yet. Now it is, with the MTB PowerBox Carbon 2x offering a 36/24 double chainring set for anyone still wanting to run a 2x group.
The original mountain bike PowerBox crankset came only with a bolt-on 1x single chainring. Now you’ve got options.
Technically speaking, you could mount a PowerBox-equipped crankarm unit to any of their modular spindles. UPDATE: But, it won’t work with any of their crank arms as originally stated, here’s why:
The spline interface between the spider and crankset on non-powermeter cranks uses a 12-spline design with a smooth round section on the back half. The powermeter-equipped PowerBox cranksets use a 16-tooth interface to add more connection points for better data.
Because of this, they don’t sell the PowerBox spider unit as a standalone part – you can only buy it pre-attached to carbon mountain bike cranks, or on carbon or alloy road cranks starting at $649. Upgrades let you enhance the system’s capabilities in an a la carte fashion. The chainline offset differs between the road and mountain bike models, so while you could technically transfer between those, shifting quality may be compromised.
For regular mountain bikes, the modular system has multiple spacers and chainring offsets to give you 50mm, 53mm, and 56mm chain lines (equivalent to standard, Boost and “Super Boost”). Some bikes and cranksets measure standard and Boost at 49mm and 52mm, respectively, so FSA’s may push things 1mm further outboard.
Some frame manufacturers had been asking for more crankarm clearance, so rather than design an entirely new set of crankarms, FSA made a 6mm longer spindle that’ll ship with 3mm spacers for each side. That moves the crankarms outward by 3mm on each side, and then you simply put a spacer between the frame and the arm or chainring. This eliminates the 50mm chainline option, but it’s typically only an issue when you have wider frames and chainstays on Boost-spaced bikes.
They’ve also added an extra wide spindle to fit BB83 frames. Those bikes use a threaded 83mm wide bottom bracket shell that’s designed for threaded bottom brackets with external bearing cups, so the spindle has to be very wide. This isn’t a common standard, mostly found on gravity bikes, but now there’s a spindle for that. That brings the total to five spindle width options for their modular platform.