Tightness during main lifts

[docoftheworld]

Dear Rip,
I started your program in 2015 at age 30 after watching your Art of Manliness videos. As a previously untrained, deconditioned individual struggling with obesity, I managed to lose weight and build some strength.
COVID disrupted my training, causing a loss of progress. Last year, I resumed the program with a home gym.
Even at my peak, I couldn't surpass a 275 lb squat for a set of five. Staying tight has always been my challenge. An SBD belt helped me break through, and now I can do 325 lbs for three sets of five. I cannot emphasize how critical the belt has been for me for the squat. However, the belt doesn't help with deadlifts, where losing tightness remains my main issue. My max deadlift is 295 lbs for 5 (lower than my squat), as the belt seems counterproductive.
I'm 5'9", 210 lbs, with a 5RM of 325 lbs for squat, 215 lbs for bench, 140 lbs for overhead press. I can do 10 chin-ups (chin over bar), but only 5 strict, full-hang reps.
Any advice on training specifically for deadlift tightness? Others have flagged my deadlift as an area for improvement to boost overall lifting performance.
Thank you for being a father figure to us all.

[Mark Rippetoe]

I your belt 3 inch, or 4?

[docoftheworld]

I apologize for not including this earlier: my belt is 10 cm (3.9 inch) wide, 13 mm thick, with a lever mechanism. I'm familiar with your 3-inch article and have closely followed your work.
I tried a Starting Strength double-ply Dominion Strength belt but didn't keep it because:
1)It was too large (I used the waist size chart, as I did for my SBD belt before reading your article).
2) I felt I appreciate more the lever mechanism's security over prongs.

I could try a smaller Dominion belt if you think it would help with tightness. The larger one, even at its tightest, didn't seem to help much (and it was pretty tight).
The tightness issue may be partly psychological. When deadlifting, I worry about re-injury. I had similar concerns with squats, but the SBD belt helps me stay tight in the hole. I never expected to squat three plates, but I did!
If you believe certain techniques can improve tightness, perhaps an article on achieving better compaction/bracing of the trunk muscles would be valuable. I don't recall a dedicated article/podcast on this topic. A discussion with Nick Delgadillo could greatly benefit lifters like me who've struggled with obesity and deconditioning, which may have hindered development of these muscles in our younger years.
Lastly, thank you for taking time to review this forum and being available to all those who appreciate you and look up to you!

[Maybach]

An Issue of Tightness | Chris Olson

The 4" belt may be impacting your ability to stay tight by moving your trunk out of position. It'll prevent you from "locking" the back in, which means the abs don't have a solid origin to anchor themselves. Try a 3" belt.

The trunk musculature adapts as well as any other musculature. Obesity and deconditioning don't impact it more than any other muscles.

The technique to improve tightness is to try as HARD AS YOU FUCKING CAN to stay tight. It's not really more complicated than that. The abdominal muscles have a very simple role. They don't move around and wiggle too much.

It's almost certainly psychological: I coach a friend who described the same problem as you and thought he needed to "do more ab work" or something stupid. Turns out he just needed someone to yell at him.

[docoftheworld]

Thank you so much for this helpful advice. Your capitalized words will ring in my ears
As for the belt, I will then purchase the smaller size belt if the consensus here is that it would really make a difference!