the steelers because the logo was just temp, they didn't know if they would like the steelmark, after it replaced the players numbers on either side of the gold helmet, Jack hart (equip manager) insisted on leaving it on one side of the gold helmet, then they finished second for eastern conference, qualified for playoff bowl, they wanted to do something special for postseason game, so they changed the color of helmet to black from gold, which highlighted the new logo. since then the logo only on one side brought on a lot of interest, and b/c of the teams success after that they decided to leave it that way