If there is one inescapable truism from the Jim Harbaugh era with the 49ers, it's this: Jim Harbaugh knew what he was doing. Harbaugh went 44-19-1 in his four years with San Francisco, taking the team to three NFC Championship Games and generally looking like one of the most valuable coaches in the league.

Good luck finding someone who thinks that Harbaugh wasn't good at his job. Oh, wait, it appears that our pals Tiki and Tierney already did that.

The CBS Sports Radio show had former 49ers running back Brandon Jacobs call in late on Thursday afternoon (you can see video of the call-in above), and Jacobs set fire to Harbaugh, ripping him for not knowing what he's doing and generally being bad at coaching.

"You know what? I have a lot of respect for Jim when I was there, before I got to know him. I enjoyed my time there, but we didn't see eye-to-eye. I knew a little bit more about football than they let on to," Jacobs said. "To be honest, that's how I was taught. To go somewhere where they didn't have route conversions was just absurd. They're just running routes against the defense, getting people killed. Size and strength is what they had and it's why they won. 

"They had great assistant coaches. But Jim didn't know what he was doing. Jim had no idea. Jim's throwing slants into cover-2 safeties, getting people hurt. That guy knew nothing, man."

Look, Jacobs was in the building and on the offense. He's a Super Bowl-winning running back. But it's sort of disingenuous to act like Harbaugh doesn't know what he's doing.

This is a guy who won huge at Stanford after taking over for a program that wasn't traditionally great. Then he went to the 49ers and won huge with a roster that had badly underperformed the last several years. Then he left and went to Michigan and immediately got them in the discussion for the College Football Playoff. 

Maybe his style isn't subtle -- and that can go for both off the field as well as on it -- but he pretty clearly knows what he's doing in terms of coaching football. There's too much of a sample size across too many different programs to argue against it.