Built ground up for desert and rock racers alike, the Spidertrax Pro Series Unit Bearing offers an entirely new level in wheel bearing technology. Massive 3.7″ (94mm) ID Timken bearings, full chromoly heat treated construction, chromoly heat treated press-in shouldered studs, and a fully integrated drive slug makes the Pro Series Unit Bearing the only racing unit bearing of its kind. The Pro Series Unit Bearing, taking racing to the next level. This Pro Series Unit Bearing uses 5/8″ (15.9mm)-18 press-in shouldered studs on a 6 on 6½” (165.1mm) bolt circle, designed specifically for Spidertrax 45 splined IFS and full floater axle shafts. Drive snout and cover sold separately. Overview Durable Full chromoly heat treated construction, massive 3.7″ (94mm) ID genuine Timken bearings, built in Loveland, Colorado. Simply the last bearing youll ever need. Compact With a span of just 1.96″ (49.8mm) from flange to wheel mount, the Spidertrax Pro Series Unit Bearing is the perfect fit for any IFS/Solid desert and rock racing application. Powerful Massive 45 splines broached directly in, full 11/16″ (17.5mm) shouldered 5/8(15.9mm)-18 chromoly wheel studs, and a piloted hub register. Simply the strongest bearing in class. Secure Spindle nuts are not only thread locked, we also use a keyed lock ring. From race start to checkered, this means never having to worry about loosening bearings.