a steering wheel having a manually adjustable palm swell is disclosed . to accommodate vehicle operators of a wide range of grip sizes , an adjustable palm swell is desired . a steering wheel having a generally hoop shaped core material is covered in thermoplastic resin and then with an outer cover . a bladder assembly is provided within the outer cover . the bladder assembly includes a bladder , a bulb connected to the bladder , the bulb having check valves on its inlet and outlet . the bulb , if depressed successively , causes air to flow into the bladder , thereby increasing the diameter of the steering wheel in the vicinity of the bladder . the bladder assembly further has a relief check valve connected to the bladder , which is manually actuated to allow air to be released from the bladder and decrease the diameter of the steering wheel in the vicinity of the bladder .