Originally Posted by Mild Al
...my guess is that you can run whatever width you want, more or less, as long as you stick to the 559 rims and tires (26-inch with the width expressed as a decimal, e.g., 26 x 1.25, 26 x 1.5, 26 x 1.95, etc.)
...so long as the tire will physically fit in the frame. If World Tour's bent uses a MTB rear triangle, I would expect it to handle at least 1.95 wide tires, as long as the rim can handle it - you don't want to mismatch the width of the rim and tire.