Dave, I believe that the grooves are there to allow airflow for drum cooling. During braking pressure is greatest along the center of the friction material since that strip is directly over the metal "spine" of the shoe. An overheated drum will "heat spot" in a circle corresponding to that contact area. Some shoe manufacturers seem to use the groove and some don't. IIRC only one shoe at each wheel (the primary?) is grooved. And yes, you can use non-grooved shoes at all positions. Pete in PA From: "Dave & Tracy" <dave-tracy.sherratt@xxxxxxxxxxxx> Subject: IML: 59 Imperial brake shoes Date: Tue, 13 Jan 2004 09:13:24 -0000 Hi can any one tell me why some brake shoes have a wide groove running = down the middle of the lining ? & can they be used with a standard plain = shoe ? ( just got a couple of sets! ) Thanks Dave=20 60 Le Baron England.