CHROMAG RIM MAGNA40 26+ BLACK 32HPlus Sized Rims for Plus Sized Tires. The Magna is specifically made for plus tires in the 2. 8 3. 0 range With a 40mm internal width, the Magna 40 is designed to suite wider plus tires between 2. 8 and 3. 0. The Magna 40 features a thick bead wall adjacent the tire to resist impact deformation, with a wider, rounded top edge to reduce sidewall cuts. The nipple spoke bed is oriented to the spoke direction to reduce weakness caused by bend in the spoke