zigzag bar = ez bar. This does help somewhat but generally speaking your bi's are stronger then your forearms and your only as strong as your weakest link sooooooo, thats why they are hurting. Just work them more and dont cheat and you will get over it. Make sure you are getting full extension on the preachers to, not the bullshit bend arm to 90* then back up, im talking arms fully extended then back up. If you are not doing them like this already your gonna drop weight like CRAZY on your curls because they are that much harder but after a month or 2 of doing them the right way your bis will be ALOT stronger.