A Distance Touring Bicycle
The most important component of a Cross Country Bike Tour is certainly the bicycle itself. The bike that I brought on my trip across Canada was customized 1985 Univega Gran Turismo. This bike is older but the make was very solid and it proved to be an excellent choice for my Cross Canada ride. However, if I had to do it again I would make a few modifications to it just to make life easier along the way.
To anybody about to do a long distance bike tour I would give the following advice.
Road Bikes vs Mountain Bikes
Cross country road biking is best done with a road bike or some sort of touring hybrid bicycle, not a mountain bike. There are a number of reasons for this, for instance, mountain bikes are typically geared fairly low which is useful for climbing steep hills but not for straight away crusing. Also typical mountain bikes are quite a bit bigger and heavier than their road bike cousins, which means unnecessary weight. Moreover, the wheels of most mountain bikes have a comparitively smaller diameter than a road/hybrid bike. What this means is that the wheels need to spin more to cover the same distance, thus causing more wear to the tires, spokes and bearings.
Wheel Size
On older road bikes, the wheels are typically 27", however in the past number of years this has slowly been moving over to a new size called 700c. Although the sizes are very close, they are not compatible. 700c wheels are cheaper these days because most road bikes use them (quantity). It is somewhat difficult to find 27" wheels these days so I suggest that anybody looking to do a long distance bicycle tour have 700c wheels.
Tire Size and type
I recommend that tires used for cross country bike touring be 1.25" or 1.375" thick and should not have bumps or knobs for better traction. Winter road bike tires typically have these bumps and they can improve traction in slippery conditions, they reduce the efficiency of the bike on flat highway.
Spokes
Not all wheels are created equal; the number of spokes on a wheel is a major factor in how durable that wheel will be. I personally recommend at least 40 spokes on the rear wheel and 36 spokes on the front. Preferably, the spokes on the back should be made of 13 gauge stainless steel if you can find them. It is possible to get cheap wheels with zinc or crome plated carbon-steel spokes but these are generally pretty weak and brittle, carbon-fiber spokes are known to be brittle and dangerous as well. If you can find them, triple-butted (three different diameters along the length of spoke) spokes are the best for long distance loaded touring because they are thicker at the ends where most of the strain occurs and thinner in the middle to provide some flexibility and movement where it is needed. (DT Swiss makes triple-butted spokes)
Handle Bars
Also I recommend that the handle bars on the bike be straight across with nice and large hand grips, not those curved handle bars which force you to crouch over far too much. The hand grips should be fairly flat with a large surface area. This should be much better on the palms of your hands as well as the bones in your wrist and arms. Until I switched to handrests like these, my hands would go numb after hours of biking.
Bike Seat
Loaded cycle tourists should use a wider split seat for their adventure. The split in the seat keeps pressure off of tender nerves in the groin and makes for an all round more comfortable journey. Remember that you may be sitting for hours on end on this seat. I advise cushy-ness.
Touring however, requires much more than just a bicycle. Please go to my equipment page to review my other recommendations. If you have questions or you have some advice you think should be on this page please contact me and let me know.