The rib tips sandwich is the one Memphis barbecue sandwich where the eater is expected to work for it, because the meat is still attached to cartilage and the sandwich does not pretend otherwise. Rib tips are the knobby strip trimmed off the bottom of a spare rib slab when it is cut to a St. Louis shape, full of fat, connective tissue, and soft cartilage rather than a single clean bone. Smoked low over wood until they are tender, sauced, and piled onto plain white bread, they make a sandwich that is half eaten by hand and half negotiated with the teeth. That is the defining trait: this is rib meat off the bone but not off the gristle, served on bread that exists mostly to soak the sauce and catch what falls.
The craft is in the cut and the smoke. Rib tips are an off-cut, which is the whole appeal: heavily marbled, collagen-rich, and cheap, they reward a long, slow cook that breaks the connective tissue down into something soft and gelatinous while the fat bastes the meat from inside. They are usually cut into bite-length chunks before or after the smoke so they can be piled rather than carved. The sauce is the tangy tomato-and-vinegar Memphis style, applied to coat the chunks and to soak into the bread underneath. Plain white sandwich bread is the deliberate choice over a bun: it is structurally weak by design, meant to be a soft mitt that absorbs sauce and fat and holds the tips together for as long as it lasts, which is not long. The cartilage stays in, and part of the texture is the soft chew of it against the rendered meat.
The variations are small. A drier build leans on the rub and skips most of the sauce; a hotter sauce sharpens the finish; some shops serve the tips on a bun for a sturdier handle, which trades the soaked-bread character for portability. Pickles and a slice of raw onion sometimes ride along for acid and crunch. The Memphis pulled-pork-and-slaw sandwich, the eastern Carolina whole hog, the Lexington shoulder, and the Kansas City burnt ends are all distinct builds with their own rules, and each of those deserves its own article rather than being crowded in here.