The second-year man leads the AFC with 315 rushing yards and his 5.9 yards per carry is the highest among all players with more than 30 carries.
The dynamic running that has powered the NFL's best rushing attack has its roots in a talk Bell had with Steelers coach Mike Tomlin in March 2013.
The two met at Michigan State the night before Spartans' pro day and Tomlin told Bell he would probably have to play at a lower weight to succeed at the next level.
"He bought into that," Tomlin said.
Indeed, Bell, who played at close to 250 pounds in college, showed up at Steelers' rookie minicamp a week after they drafted him and weighed in at 244 pounds.
Bell dropped about 20 more pounds over the course of his rookie season and is currently at the weight that, to paraphrase Tomlin, obviously agrees with him.
"He ended last year in the mid-220s. He reported back this year in the mid-220s," Tomlin said. "He has shown he is committed to maintaining a level of conditioning over the course of a 12-month calendar and he has taken off from there. I think his play is reflecting that."
Is it ever.
Bell, who uses patience to set up his blocks, has also shown the kind of quickness and burst that was not evident until the end of last season when the 2013 second-round pick was finally healthy after missing the first three games because of a sprained foot.
He is second in the NFL in rushing, and with the offense running through Bell the Steelers lead the league in rushing with 163.3 yards per game.
Bell is not the only reason why the Steelers have dramatically improved in running the ball after averaging 86.4 rushing yards per game last season.
LeGarrette Blount is averaging 7.8 yards per carry, and he ripped off a 51-yard run in the Steelers' 37-19 win against the Carolina Panthers. Bell had broken free for an 81-yard run earlier in that game.
Last season the Steelers' longest run was 43 yards, and the big runs turned in by Bell and Blount against the Panthers are part of the mounting evidence that Pittsburgh has the best running back tandem in the NFL.
"He's really another starting running back," Bell said of Blount. "He could go anywhere and start."
And, Bell said, don't forget about Dri Archer.
The rookie running back has been out since spraining his ankle in the Steelers' season opener. But his speed and versatility allow the Steelers to use a bunch of different formations and force teams to account for Archer, who may play Sunday against the Tampa Bay Buccaneers.
"You've got to respect him because he's arguably the fastest player in the league," Bell said. "We all know what (Archer) can do. He gets the ball in open space, he's going to be gone. He and (Steelers wide receiver) Darrius Heyward-Bey are the fastest two players I've ever seen live. We've got plenty of weapons. This offense is only going to get better."