The evolution of the revolution. 15 years ago, the original Cannondale HollowGram crank started the BB30 revolution and set a new standard for ultra-light, super-stiff cranks. The most current evolution of the HollowGram, the SiSL2, continues this tradition of radical innovation. These hollow cranks are created by bonding together two machined, heat-treated clamshell halves with a super-strong anaerobic bonding agent. Extensive FEA modelling and physical testing have allowed us to ref ne the internal and external shapes for the ultimate in stif ness-to-weight. The result is a crank light and stiff enough for our top road race machines but still so tough, we use it on our mountain bikes as well. Compatible with all Cannondale Si Spiders and SpideRings.
Back in 2000, Cannondale revolutionized bottom bracket technology by oversizing the bottom bracket shell and replacing the heavy, flexy steel BB spindle with a 30mm aluminium spindle with a unique, stress-reducing wave-taper crank interface. The result was BB30, a system that is not only significantly lighter, but also significantly stiffer than traditional designs. We released the design as a free industry standard and the rest, as they say, is history. BB30 is now available in many different spindle widths and and configurations to fit different designs but the 30 mm spindle and wave-taper crank interface remain the same.
An example of this is the new BB30A found on the Synapse. The "A" stands for Asymmetric - the BB30A adds 5mm to the non-drive side of the BB shell for a wider, stiffer base. To accommodate the wider BB shell, the BB30A gets a longer spindle and the non-drive side crankarm angle is changed to maintain the same Q factor and even out ankle clearance on both sides. Cannondale Hollowgram BB30A cranks will work on both BB30 (68mm BB width) and BB30A (73mm bb width) by changing the non-drive side spacers.