Precision is paramount in custom manufacturing. You must confirm the tolerances for bottom bracket shells (BSA, BB30, or T47) and head tube diameters to ensure compatibility with global component brands like Shimano or SRAM. For disc brake frames, specify Flat Mount or Post Mount standards and ensure dropout spacing (e.g., 142x12mm thru-axle) is exact. Request CAD/BIM drawings for approval before production to verify reach, stack, and tube wall thickness, which directly impact frame safety and ride quality.