Are you sure you want to get mountain bikes? Mountain bikes have stronger wheels, because of the smaller diameter but they are rarely used for touring. Actually I am not sure what they are used for to be honest. [IMG]/img/vbsmilies/smilies/biggrin.gif[/IMG] Maybe some very rough terrain where the suspension makes a difference. Some touring bikes are also offered with 26' wheels because of that but they are not that common.
For touring on bad roads, a good purchase would also be a cyclocross bike. These bikes have these advantages over a mountain bike:
-A soil-mud setup for gravel roads and muddy patches, with similar performance as a mountain bike. Maybe not as strong wheels though.
-A drop bar handlebar which helps alot in windy situations. Many cyclocross bikes also have a second set of levers on the horizontal section of the handlebar when you are not riding on the hoods.
-Many cyclocross bikes have disk brakes now. Disk brakes help alot when in wet conditions, but they have a weaker performance due to the torque force applyed. The rim brakes are stronger because they generate more torque due to the greater distance of the force applyed to the hub of the wheel. But if its rainy you will need to be careful or consider more aggresive pads. Disk brakes dont ruin the rim of the wheel but the setup is somewhat heavier.
-A cyclocross bike is very often used for commuting. In fact many models are advetised as ideal for commuting and many of them are offered with mudguard and rack fittings.
-They are much lighter then mountain bikes, making them better for climbing. They are also "faster" due to the larger wheels. You can change tires according to the situation. Actually for most roads which do not have big rocks or gaps any wider tyre would provide as much damping as you need making a suspension fork unecessary.
You have a choice of aluminium or cro-moly steel. The second is supposed to be more "shock absorbent" and have a longer life due to the higher fatigue damage resistance. The first does not corrode and some times is offered with hydroformed tubes. Touring bikes are pretty common in steel. Some are actually cyclocross bikes, e.g. the Surly Crosscheck which is a cross bike and its advertized as ideal for commuting and light touring.
