Is your Sole SB900 flywheel drifting side-to-side, or have you noticed a clicking sound from the crank assembly?
The Sole SB900 Indoor Cycle is built for high-intensity commercial use, but its heavy 48-lb flywheel and high-torque crank arms are held in precise alignment by a small but critical component: the C-Ring (External Retaining Ring). These hardened steel rings sit in machined grooves on both the crank axle and the flywheel axle. If a C-Ring snaps or loses its tension, the axle can shift laterally, leading to belt misalignment, pulley rubbing, or permanent damage to the sealed cartridge bearings. Our Genuine OEM Sole SB900 C-Ring is the factory-authorized fastener designed to keep your drivetrain locked and centered.
Because the SB900 is a "fixed gear" bike with significant rotational inertia, these rings are under constant lateral pressure.
High-Tensile Spring Steel: Heat-treated for maximum "spring" memory, ensuring the ring snaps into the groove and stays there, even under the stress of heavy climbing or high-RPM sprints.
Precision Gauge Thickness: Specifically measured to fit the standard grooves on Sole crank and flywheel axles. An "almost-right" hardware store ring will allow for "play," which eventually destroys the axle's surface.
Corrosion-Resistant Finish: Treated to resist the salt and moisture from sweat—the #1 cause of hardware failure in indoor cycling.
Universal Sole Fit: This retaining ring is the standard size used for both the Crank Axle and the Flywheel Axle on the SB900, as well as the SB700 model.
A missing or damaged C-Ring is often the "hidden" cause of drivetrain noise. When the ring fails, the axle begins to slide horizontally. This causes the belt to track improperly, leading to fraying and a loss of power. More importantly, it can cause the crank arms to strike the bike's plastic shrouds. Replacing the C-Ring during a bearing swap or belt adjustment is the best way to ensure the long-term structural integrity of your bike’s drive system.
Replacing a C-Ring is a quick task, but it requires External Circlip Pliers.
Access: Depending on which ring failed, you will need to remove the crank arm (using a crank puller) or the flywheel nut.
Removal/Install: Use the pliers to spread the ring just enough to slide over the axle and into the machined groove.
Pro Tip: Do not over-spread the ring. Stretching it too far can permanently deform the steel, causing it to fit loosely in the groove and potentially fly off during a ride.
Lock in your performance. Keep your SB900 centered.