+// [outer_diameter, width, inner_diameter, uses_guide]
+
+// 608 [standard skate bearings] with bearing guide
+bearing_608 = [22, 7, 8, 1];
+// 608 bearings with fender washers. Not good at all, the belt brushes against the carriage
+bearing_608_washers = [22, 10, 8, 0];
+
+// one 625 with guides
+bearing_625 = [16, 5, 5, 1];
+// two 625 - for use without bearing guides.
+bearing_625_double = [16, 10, 5, 0];
+
+// those two here are really good:
+bearing_624_double = [13, 10, 4, 0];
+
+// this one has roughly same diameter as pulley, makes belt parallel so its prettier
+bearing_623_double = [10, 8, 3, 0];
+
+idler_bearing = bearing_624_double;
+
+// Select carriage lenght ******************************************************
+// 30 for single carriage extruder (two holes with centers 30mm apart)
+// 50 for wade or single with fan (three holes, 30-20)
+// 80 for full length carriage (four holes, 30-20-30)