You’ve heard me refer to this previously in the Sugar Bowl write-ups. UGa uses it as their base defensive front. So does Texas. You’ll see it again from LSU next year on nearly every snap. This is one of the most important trends in FBS defenses today and the importance is only growing. Get used to hearing about it even if it doesn't get as much press as the sexier pass defense schemes.
What is it? The Tite Front stars with a 3 man DL that aligns with 4i-0-4i techs. IOW, 2 DEs play inside eye on the OTs and a 0-tech NT. Behind them are 2 ILBs – Mac and Rover in Orlando’s terminology with an OLB (Buck or Jack LB) setting one edge. The other edge is usually controlled by either a 4th LB (Sam) or 5th DB (Nickel Back).
Why use it? It shuts down the A-gaps using the NT and one or both ILBs. It threatens both B-gaps with the inside shade 4 techs. It discourages teams from pulling guards due the ability of the 4i DEs to pinch down and follow the guard to the ball. And it does all of that with 5 players, usually leaving a free hitter while spilling runs to the outside. The 4i shade makes it easier to double the DE with the guard and tackle but then you’re likely using 5 OL to block 3 DL, leaving the LBs completely clean.
RPOs take advantage of conflicting LB responsibilities. A favorite uses either inside zone or power run with a pass option to the backside slant. The QB reads the backside OLB like a read option. If the LB crashes down, throw the slant instead of a QB keeper since he’s the underneath coverage for that pattern. If the LB stays to the outside, the QB hands off. The 404 Tite Front helps stymie this by spilling the play, forcing the RB to slow down and cut to the outside toward run support from the secondary. The backside OLB (or NB) can hang out there in space to clog the hook/slant zone against the RPO pass.
What are the weaknesses? There is no big run stopper to set the edge and control the C-gaps, like a 4-3 DE. The secondary has to come up in run support and be effective once the play is forced outside to them, much like a safety running the lane against the triple option. The critical role as run stoppers can create opportunities for vertical routes over the top. Many teams have judged this tradeoff to be worthwhile to stop the horizontal stretch and shorter vertical stretch aspects of Spread Offense from gashing them on long, sustained drives.
There’s a lot of complexity and variation behind the basics. I just wanted to cover the what and why behind the switch to 3 down linemen across FBS so people can see how defenses are adapting to the Spread. For those who want more detail these articles are a great start:
https://www.sbnation.com/college-football/2019/2/5/18205641/tite-front-defenses-explained
https://www.footballstudyhall.com/2018/2/19/17021322/college-footballs-new-favorite-defense-4i-tech-4-0-4-georgia-texas
https://matchquarters.com/2016/10/10/the-3-4-tite-front/