Triumph changed tank styles for the America/Speedmaster in about 2008. They now hold around 5 gallons and it is kind of flatter and wider. One of the good things I see about the new one besides holding more gas, is the there is no "lip" around the bottom edge of the tank. Some people think they are fugly.

"Catching a yellow jacket in your shirt at seventy miles per hour can double your vocabulary" Author unknown