Originally Posted by
Carbonfiberboy
I finally found a rolling resistance test which compares various widths of tires and various models, all inflated to the maximum pressure written on the sidewall...
The "maximum pressure written on the sidewall" has nothing to do with optimum pressure for a given load, nor is there an equal relationship with that number across all manufacturers. The max pressure number written on sidewalls is the result of a test to see at what maximum pressure a tire (actually group of tires) will remain seated on a given rim (there is no test rim standard BTW), divided by two.
http://www.bccclub.org/documents/Tireinflation.pdf see third paragraph of MAXIMUM INFLATION PRESSURE. Sorry, that table of rolling resistance testing is flawed.
Originally Posted by
cplager
...if you have a skinny and an fat tire at the same pressure, they have the same size contact patch...
Except you're omitting the effect rim width has on contact patch shape & area, and assuming the tire is static.