In bicycle touring there are many types of gear that we use. What they all share in common is that there are many potential options to choose from in every type of gear. Each item plays a critical part in the process that revolves around the selection of the one that ultimately works really well. If the best option just doesn't seem good enough, I try to creatively modify it to make it a better fit for touring. None of the modifications that I make to gear are difficult. From my very first tours I've cut the pockets out of, and off of, shorts and pants. I've never slept on a full-size foam sleeping pad, I've always chopped them down (currently down to 4.4 oz.). I don't need a whole tooth brush or hair brush, when half of small ones do quite well. And I modify containers. Food is never stored in boxes or jars, but plastic bags and plastic tubes (peanut butter). I pare down shampoo and toothpaste tubes to the tiniest sizes. I simply try to find or create the most advantageous version of any type of gear no matter how small. I select and modify gear to develop a touring-specific version of almost all types of the gear that I carry.
I think to myself that pounds are pain, so I've shopped and I've chopped. I've tried to find the best performance-to-weight ratio in every piece of gear that I use, especially amongst the gear that weighs the most: tent, sleeping bag, rain gear, clothing. My 850-fill goose down bag is rated to 20 degrees and weighs 1 lb. 12 oz.. I absolutely would not use a synthetic-fill bag, perhaps with the exception of world-rounder. I hand wash regularly on the road, I take little spare clothing. It would be impossible for me to overstate just how important gear selection and modification is. As I've said, more than anything else (with the exception, possibly, of the reduction in weight of outer-wheel components) it defines the performance of a touring bicycle.
Once you've gathered all of your gear together, you've got to find out how much space it takes up. You'll want it to take up as little space as possible. If gear can be compressed, compress it. For instance, if you roll your down jacket up tightly it will still take up a lot more space than it will if you stuff it in the smallest stuff sack (and lightest) possible. You'll want to make sure your other gear is packed as efficiently as it can be. Your cooking pot will serve you best if it is filled with gear before it goes into your panniers. A spare shirt and rain gear can be rolled up very, very tightly and then secured with a couple of rubber bands, or even better, a tiny bungee band that you've made yourself, so that they'll stay tight and won't unroll inside your panniers. A drinking cup can be filled with a spare pair of socks (generally, clean ones are the first choice). Work at paring down what you've got.
When you've got your gear mashed and stuffed and rolled and trimmed down as far as it will go, put it in a box and measure the amount of space that it takes up (length x width x height). Weigh it all. What you come up with will determine whether you can use a single pair of rear panniers, and that's the goal in Phase One: to carefully select gear so that you can take a cross-country trip with a single pair of rear panniers and avoid all of the wind resistance, and the resistance of the weight of gear, that is carried on a front rack and panniers. And when I say “rack and panniers” I don't mean just any rear rack and pair of panniers, either. There are vast differences in the design of racks and panniers that have a great impact upon performance, which I'll discuss in Phase Three.
As I've mentioned, I try to stay below 20 pounds in the combined weight of rack, panniers, gear and food, and I never go over 25 before I balance some gear on the front end of my bike. The total weight of gear is critical, but loading and stabilizing gear is also very important. Rack stability, pannier stability, pannier shape (especially depth), pannier compression and the lateral, vertical and fore/aft loading of gear all play an important role in Phase One. Within Phase Three, which is coming up shortly (Phase Two is very brief) I'll present a very in-depth discussion of gear loading, along with pannier and rack design, that plays a very important role in performance.