When I knit a rib pattern with straight needles i.e. going back an forth it is a nice "tight" rib which also gives elasticity. However, when I knit a rib in a round e.g. the cuff of a sock the ribbing is very loose and doesn't "hug" the ankle or for a sleeve the wrist. Does anyone know if there is a solution or this is just the way things are?
The ribbing should have the same elasticity whether you knit flat or in the round. How are you knitting in the round, dpns, magic loop? It may be that your tensiion is more relaxed when you knit in the round. You could try dropping down a needle size or two for the sock ribbing only, to see if that helps tighten things up.
I usually knit my sock ribbing with needles one size smaller and I always do a K1, P1 rib for my cuffs. I think you run into the "loose" problem when a 2 x 2 or larger rib is knitted for the cuff.