Weight weenies rejoice! FSA has figured out a way to shave a few grams from conventional steel headset bearings while retaining comparable levels of durability. As the exterior dimensions are unchanged, they're also a drop-in replacement for easy installation.
FSA's new 'SL' headset bearings use the same steel inner race and balls as its standard all-steel bearings. Instead of the typical all-steel outer race and casing, though, the SL bearings use an abbreviated steel race tucked inside an aluminum shell.
Weight savings are substantial in terms of percentages with the SL bearings as much as 38 percent lighter than conventional bearings, according to FSA. The reductions are more modest in terms of actual mass, however – just 7.7-9.2g depending on size.
FSA will offer the new SL bearings in 45° x 45° (for 1 1/8", 1 ¼", or 1 ½" steerer diameters) and 36° x 45° sizes (1 1/8" and 1 ½" steerers only). Retail price is US$29.99 apiece.