Up until last year I had a 11-year old Brinkmann charcoal grill, I used it for smoking ribs, shoulder, chicken, and it worked amazing. I just rigged it up for indirect heat and the results were great. I literally used it until the bottom fell out. Last year I got a Chargriller with an offset smoker box. I'd been wanting to try the offset box to see if I could get even better results, and also triple my capacity. I got it last spring and to date I'm still not happy with it. The first few times I used the offset box for the wood it wasn't great. It took gobs of wood to get the main chamber up to 225 F and keep it there for 5-6 hours. And the ribs just were off. So I've stopped using the offset box and put the wood/heat source under the main chamber off to the right side with the ribs on the racks over to the left under the pipe. I still gain some capacity. I just did some back ribs yesterday and, again, the result was good, but not great.
We like our ribs fall off the bone. I know that's not what the competition pitmasters go for, that technically 'fall off the bone' is overcooked, blah blah blah. But that's the way we like it, and that's the way I could get it with my previous grill. I can't get there with this one.
The Chargriller is probably 20% bigger in terms of space in the main chamber. With my previous grill I'd get it to 225 F and keep it there and it was perfect. I found that with the new one I needed to get it to 240-250 F to get the job done in the same 5 hour window (2-2-1). But I'm still not getting it to the fall off the bone place. So I still must be undercooking (or not properly overcooking ).
I would recommend cranking up the heat once you wrap them in foil (~300 if you can get it there) - basically the same as cooking them in the oven for about an hour. Put a little liquid with the foil (apple juice, whatever your fancy) and you should get to fall off the bone tender.
For those of you who foil the ribs after letting them take on as much smoke as they can, do you wrap the foil tightly or loosely? I spray with apple juice and wrap tightly, which is how I did it before, but am thinking maybe I should wrap loosely to let the ribs steam better. I think maybe I need to switch it up to a 2-3-1, and let them go with the foil longer. I'm not seeing the ribs pull down at the ends exposing more of the rib bone as I would before.