That was a great response; thanks very much, Ogden. My main reason for wanting to get a mountain bike is that it seems to me that it will be more sturdy and hence more able to take my weight. Is this irrational? The thing is that when I was in my late-teens (and probably weighed slightly more than I do now, but not much), I was on a 10-speed road bike (thin tires, light frame, etc), and the front tire literally just crumpled after I ridden it for maybe 45 minutes. I mean it literally turned into an oval, and I hadn't hit anything with it, etc. I was, as you'd imagine, totally mortified and consequently I haven't gotten on a bike since. What I'm afraid of, really, is that happening again, especially if this time I was 20 miles from my house (which wouldn't be impossible since I'm now in much better shape than I can remember being in my life, even though I'm still quite overweight). Is this fear not rational?

Also, from anyone, I'd take some brand-name recommendations if you have them. Finally, any thoughts on "urban" bikes or foldable bike? I can't imagine any of the foldable bikes are sturdy enough, but I thought I'd ask.

Thanks again; that was a tremendously helpful post.

-j.