Originally Posted by Knig
Maybe after a few more weeks I'll lose the belt and see how it feels
I think that's a very good idea, but don't wait a few more weeks. Lose it now. If you keep getting heavier in the next few weeks with the belt when you take it off your weights are going to decrease significantly. If you don't decrease them you could end up with just the kind of injury you've been trying to avoid simply because you've allowed your core to weaken like Kane said.
If you can't keep you back straight then lower the weitght...and work on strengthening your back with other lower back exercises and of course work you entire back.
I would forget the knee wraps too.
I posted an article
Back Strong and Beltless
Very long and highly technical and you probably don't need to memorize it or anything but it gives a very concrete idea of what a belt does and doesn't do.
Originally Posted by Kane
If I was deadlifting 600lbs then it would be a diff story...)
Exactly. There may be a time or a stength limit where a belt is necessary. 0311 has suggested to me that when you are lifting 2 to 2.5 times your bodyweight then a belt is advisable. Also at times when you are going for a big PR then I don't see anything wrong with using a belt...but it should not be a regular part of your training IMO.