Direct mount rim brake frames use two bolts instead of one, and if your frame is set up that way, you can't just bolt on a standard SRAM caliper — you need a direct mount caliper specifically. The S900 is SRAM's answer here, and until this brake existed, SRAM-sponsored pro teams were quietly running Shimano Dura-Ace direct mount calipers on their SRAM builds because SRAM didn't offer one. If you're building or refreshing a rim-brake frame with direct mount bosses on the fork and seatstays, this is the caliper that lets you keep the group all-SRAM.

The two-bolt direct mount interface is the whole point. Spreading the mounting load across two bolts instead of one central pivot reduces what SRAM calls splay force — the tendency for the caliper arms to flex outward under hard braking. Less flex at the caliper means more of your lever input goes into pad-on-rim energy rather than frame and fork deflection, which is what people mean when they describe direct mount brakes as feeling more solid at the lever.

One thing to sort out before ordering: front and rear are model-specific and not interchangeable. The front caliper mounts to the fork crown, and the rear is designed for seatstay mounting only — there's no chainstay-mount version of the S900. Check which one you need (or both, if you're doing a full swap) and match the SKU accordingly. The caliper is also lever-specific to mechanical actuation — it works with SRAM's non-hydraulic road levers including Red eTap, Red, Force, Rival, and Apex, but not with HRD hydraulic levers.