I have been having to do lots of extra grinding on Sidewinders for 3/8ths just depending on what rocker is used so I went to 5/16ths and it makes life EASIER--Smith Brothers has assured me that at 9 inch length range ( typical 440) that a 5/16th .080 wall is good to 700 open so more than covers any street application --they make .120 wall for folks that can't sleep at night--I would never do it in race application with big roller but that is not what they are all about anyway