This model is a spherical outer ring type of model NAST.
Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R).

Model No. Main dimensions Basic load rating Detail specifications CAD Dimensional drawing Inner  diameter di Inscribed bore  diameter dr Outer  diameter D B C Dynamic rating C Static rating C0 2D (DXF) 3D mm mm mm mm mm kN kN NAST 6R 6 10 19 10 9.8 4.12 4.55 NAST 8R 8 12 24 10 9.8 5.68 5.89 NAST 10R 10 14 30 12 11.8 9.7 9.67 NAST 12R 12 16 32 12 11.8 10.4 10.9 NAST 15R 15 20 35 12 11.8 12.3 14.3 NAST 17R 17 22 40 16 15.8 17.4 20.9 NAST 20R 20 25 47 16 15.8 19.2 24.5 NAST 25R 25 30 52 16 15.8 20.7 28.4 NAST 30R 30 38 62 20 19.8 30.3 45.4 NAST 35R 35 42 72 20 19.8 32.2 50.6 NAST 40R 40 50 80 20 19.8 35.7 61.6 NAST 45R 45 55 85 20 19.8 37.1 66.4 NAST 50R 50 60 90 20 19.8 38.7 71.8