Chainstay Length
One of the more important measurements on a touring bike is the chainstay length. A longer chainstay length is desirable to increase the wheelbase (making the bike more stable at speed) and to provide ample heel clearance from the panniers. Heel clearance is especially important for riders with larger feet (size 11-13 / 46-49) as your feet can sometimes strike the rear panniers when you pedal. That said, there are rear racks that push your panniers further back if you need.
Chainstay Length Comparison of 57cm Bikes:
Touring bike 445-470mm
Road bikes 405-415mm
CX 420-435mm
Wheelbase
A longer wheelbase provides a more stable and comfortable ride. Touring bikes have a long wheelbase due to a combination of a slack head angle, long fork rake and long chainstay length.
Wheelbase Comparison of 57cm Bikes:
Touring bikes 1050-1070mm
Road bikes 996mm
CX 1018mm
Bottom Bracket Drop
Bottom bracket drop determines how high your cranks sit from the ground when you pedal. A lower bottom bracket results in a lower saddle height and therefore a lower centre of gravity.
Touring bikes may need pedal clearance over obstacles, so some manufacturers provide a high bottom bracket (53mm drop with 700c wheels). This is generally offered on off-road touring bikes. Other manufacturers provide a low bottom bracket (78mm drop with 700c wheels) to maximise the stability of the bike, albeit at the risk of pedal strike at times. This is more common with the road-oriented touring bikes.
