How to have bigger biceps : 15 - Opt for a wider grip :

👉 14 - Opt for a tighter grip

15 - Opt for a wider grip :
You will develop the short head of the biceps by making a wide grip on a bar, even on a bar wider than the shoulders, or lifting dumbbells as far as possible from your body. 

Even though a standard shoulder-width grip allows the short biceps head to be solicited, many people will begin with that part of the muscle that is already more developed than the other parts.

👉 1 - Perform forearm flexion at the bar