These inner tubes were marked as 15x6.00-6 but they were NOT that size, regardless of what they wrote on them. The tubes were too narrow and forcibly pulled the stem back in the rim when inflated. No, the stem didn't fall in; it forcibly pulled in as the tube inflated due to the tube distorting. No, I did not install them wrong. These tubes were unusable. The ones I purchased here would not work. I went to farm supply store and purchased two 15x6.00-6 inner tubes - they worked great on the first try. Putting real 15x6.00-6 inner tubes beside these, both deflated, there was a visible difference in size. They were not only a waist of my money, they were a waist of my time which was even worse. I lost time both waiting for delivery and taking the tires off the rims several times trying to get the tubes to work. Not only that, I had to drive 45 miles round trip to get real 15x6.00-6 inner tubes.