So I decided to check it out, tuned low E do D, played with it for few minutes, came up with few riffs that the new tuning allowed me to play, aaaand.. the string snapped, right at the bridge. And the string was pretty thick (52). Why would this happen? Where could I go wrong ?

I really have no idea how dropping a string's tuning could lead to a snap..

I suppose if there were a kink or some sort of weak-point, a release of tension could somehow affect it, but I doubt this would lead to a string snapping..

You didn't by chance tune it UP to D did you? >.<

If your Bridge has a Burr on it, it would cause it to break. Might need to get into that saddle with a file and smooth it out or at least lube it.

That's what she said.

Yep. That's what happened to me when my string broke at the nut from tuning down. I found it to be some royal BS.

You'd be surprised. Old strings have virtually NO life in them, as proven when I dropped my guitar from standard E to drop C and lost my high E in the process of down tuning it.

Drop D is awesome btw. If you want some really exciting stuff to do in drop D, then look at either Lamb Of God - Laid To Rest, or Killswitch Engage - Rose Of Sharyn. The main riffs to both songs are fucking awesome to play

(Yes I know KSE is drop C, but a drop is a drop ok?)

Graph Tech FTW!