638 Dim. is + .005; 750 Dim. is + .005-.000.
Unit of Measure
Items
Idler Ball Bearing

Ball Bearing Idler Sprocket Hardened Teeth

Idler Ball Bearing

40BB17H Ball Bearing Idler Sprocket Hardened Teeth

Idler Ball Bearing

Ball Bearing Idler Sprocket Hardened Teeth

Idler Ball Bearing

Ball Bearing Idler Sprocket Hardened Teeth

Idler Ball Bearing

Ball Bearing Idler Sprocket Hardened Teeth
No. Teeth N/A 20 N/A 17 N/A 18 N/A 15 N/A 17
Chain Size N/A 35 N/A 40 N/A 40 N/A 50 N/A 50
O.D. N/A 2.600 in N/A 2.970 in N/A 3.140 in N/A 3.320 in N/A 3.720 in
B N/A 0.638 in
L N/A 0.720 in
W N/A 0.168 in N/A 0.284 in N/A 0.284 in N/A 0.343 in N/A 0.343 in