The Federal Stance XL rim has a wider (40mm) cross section which is designed to be in keeping w/ modern tire sizes which helps the tire maintain its correct profile. The triple box section combined w/ the wider profile makes the rim both stronger & stiffer than conventional rims & also helps to reduce the possibility of pinch flats. The wall thickness where the nipples are located has been increased by 22% to reduce the possibility of spokes pulling through the rim. Federal have also changed the material from Aluminum 6061 to 6066 which increases the strength by approximately 30%. The rims have a lower sidewall height (15mm compared to 20mm on most other rims) to give the rim a lower/wider appearance. The internal sidewall height is also reduced to keep the tire firmly in place when inflated & the base of the rim is sunken to ease the installation & removal of tires. Supplied w/ an XL rim tape.