Build Bigger Biceps with a Countdown Cluster Set of Dumbbell Curls and Chin-Ups. This method allows you to push closer to true muscle fiber mechanical failure than straight sets (or even supersets). You're going to go back and forth between a curl variation (any dumbbell or barbell curl) and a close-grip chin-up. For curls, use a weight you could get about 12 reps with. You'll need to be strong on chins, too. You'll start with 5 reps of each, then 4 reps, then 3, then 2, then 1, taking no rest i