Losi LOSA6944 15 x 21 x 4 Shielded Ball Bearing 2 Muggy LST XXL

The Losi LOSA6944 is a pair of 15 x 21 x 4mm shielded ball bearings built for the Muggy, LST, and XXL. Shielded bearings keep out larger debris while maintaining smooth, low-friction rotation, and this larger size supports higher-load rotating components on these big-block nitro platforms, such as clutch bells or transmission shafts.

Because these bearings support components that see significant torque and heat during hard running, they're prone to wearing faster than bearings in lower-stress locations, and a worn bearing here can translate into noticeable drivetrain drag or unusual noise under load. Replacing bearings proactively as they show wear is far cheaper than dealing with the damage a seized bearing can cause to surrounding components. This genuine Losi pair matches the factory 15 x 21 x 4mm specification, so they drop into your existing bearing bores without modification. Keep spares on hand for routine maintenance on your Muggy, LST, or XXL.