Ok how much weight is too much? With my weight being well over 300lbs how much pannier weight can I add to my racks before I blow out the tires or wheels? I currently use Marathon 700x45c tires on the disc trucker and only had a small packed bag with clothes and my laptop for work but it felt like the rear tire and rim were about to detonate. At my current weight (6'6'' and 350lbs) there will be no way I would be able to go on an extended tour with more gear.

I know, I know I need to keep peddling and reduce my weight but any other "super clydes" like me out there who have experience pushing their bikes to the limits and if so what were your results?