The top of the wide belt actually rides a little above the rim of the pulleys. The origional belts rode down and in the "v" of the pulleys. I bel;ieve that there is more surface area of the belt in contact with the pulley with the wider belt riding high in the groove. I have to keep the alternator shut off while starting the engine due to load and I only energize the field while at idle. There is quite a load when the big alternator kick in. I used to have the Balmar delayed / ramp up volt regulator but it stb and I refuse to spent the money on a new one just for the ramp up feature. I have a simple switch on the battery power to the volt regulator now.