[kdml]

Went to the auto parts store to buy new rear wheel cylinders for my '87 3/4 ton 4x4. They asked me if I had 13" or 11" drums. I have 13" and they said they only had the 11" in stock. The 11" looked to be the same size as the ones I pulled off the truck. Are there different size wheel cylinders for 13" vs 11" drums. I thought the only difference was SRW and DRW wheel cylinders (I have SRW).

Thanks
Doug