If my experience is at all representative*, backpack makers must despise rack and pannier makers. I have commuted with panniers for the last couple of years. Recently I had the pleasure of taking my Trek 520 (build update coming soon) to work and back a few times as I tested it out and tweaked some things. The bike has no racks yet and thus can't carry panniers, or as some call them, saddlebags. So, I went back to how I used to do it and strapped on my trusty old backpack.
I didn't like it at all. Here's why:
1) Sweaty Back - Going by all the crap I read, this is perhaps the most popular reason for disliking backpacks and is quite self-explanatory.
2) Shifting Load - I suppose if I had the straps better adjusted, this wouldn't have been a problem, but the backpack also would have bound my jacket even more tightly to my body, exacerbating problem number 1. My backpack shifted around when I was making turns and stuff and I had to compensate by changing my body position a little. I didn't like that.
3) Higher Centre of Gravity - Riding with panniers, I have become accustomed to a very stable bicycle (particularly in the rear) with a nice low centre of gravity. Carrying more weight up high felt pretty weird and less safe, although I suspect I could adjust to this pretty easily if I had to. After all, Mutant Winter's load rides pretty high too (although not as high as a backpack).
4) The Principle of the Thing - Before I used panniers, I wouldn't have had the following thought, but here it is. Given a choice, why would one strap a load to oneself rather than letting the machine carry it? It is kind of like inventing the first wagon and continuing to carry the basket of wheat on your head, or going to the grocery store in your car and carrying the food home on your lap. Machines are supposed to help us out with this kind of thing.
I suspect that people who get a rack and some panniers may never go back to the backpack unless, like me, they have no choice. This is also the reason that if I were a backpack maker, I would hate rack and pannier makers. Thankfully for them there are still lots of people who don't ride bikes often enough to invest in racks and panniers and who will stick to the backpack they use while on foot. Keep the up-tick in utility cyclists going, though, and there could be a rack/pannier vs. backpack showdown, or even shootout! That would be so cool! Oh Crap. I have just been struck by WTF syndrome again:
Ah well. It is what it is.
* In the course of writing posts for this blog, I have come to realize that my experience and reactions and opinions may not be representative of normal people in any way, shape or form. Let me know if I am preaching to the choir or way off base in the comments!
Hey, Take A Load Off.
R A N T W I C K
PS - Please note that I did not mention messenger bags. I have never owned one, so I can't reasonably comment on them. Perhaps you could, though.