AJS/Matchless Rear Wheel Sprocket/Brake Drum rear wheel, 6-hole fixing f. all WD Mod. and some Post war Mod. G3, G3L, G80 Rigid Mod. 42T Holes = 5/16" x 26 TPI Brake Drum ID: 6" - 140 mm Chain size 110-056 (chain 530, 5/8" x 3/8") Mounting bore: 2" Overall width 1 7/16" - approx. 36.5 mm Hole center to center opposite: 2 9/16" - 65 mm Made in England