Originally Posted by
SoSmellyAir
For a more upright posture, looking for a higher stack to reach ratio. Among the 3 bikes you posted the Cannondale Synapse would have the highest stack to reach ratio. In addition, please see below ...
In addition to the stack to reach ratio, we also need to consider the maximum spacer height under the stem. On my (now two generation old) Cannondale Synapse this number is 55 mm, but on a Canyon Endurace it is only 37.5 mm. This is a significant difference.
The Trek has the highest stack height and shortest reach which with all else equal would lead to a more upright ride.
The Cannondale has the shortest stack height and longest reach which with all else equal would lead to a less upright ride.