getting to the last steps in firing up my wsm. when i got my new grates i noticed that the lower cooking grate is more substantial than the upper grate. thicker rods and two bars running across underneath the cooking rods. any reason for this? course i will have to weld two rods on the ends of the coal grate to prevent coals from dropping through.

I belive all the charcoal grates are heavier do to the direct contact with the harsher enviroment i.e. the fire itself, acid from the coal ash ect. JM2

Weber used a lot of the parts it already had to construct the 18" WSM. The lower 18" WSM cooking grate is a nickel-plated version of the 22" kettle charcoal grate.

so they took the charcoal grate and nickel plated it to work as the 18 wsm lower cooking grate. great idea.