I was always under the assumption that the larger diameter line, the deeper a crank bait will run. I recently read an artical that contradicts that theory. The artical said that a mid depth crank (8-14') is best used with 8lb mono. With that same crank but 15lb mono the crank should only dive to a little over 5'. Is this true? I don't use mono, I use Dawia Samauri Braid in 55lb test which has the diameter of 10lb mono. What I thought I have been doing using an equivelant 10lb diameter line was making a 2-5' crank run more like 3-7' Am I getting the max depth + out of my crank, or is my crank running way more shallow than I think?

The smaller dia. , the deeper the bait goes.

Bass-Brat got it right. Thinner braid will give you more depth. Most 50lb braid is the equivalent of 12lb mono. To get to 8lb mono dia you need 30lb braid. I have been using 10lb suffix performance braid which is 2lb mono equivalent this year & I'm amazed how quickely cranks get down to the bottom in 15-20 feet.

This article by Mike Iaconelli gives some helpful tips about crankbaits, some specifically about line diameter:

http://www.bassresource.com/fishing/iaconelli_crankbaits.html