Originally Posted by
ScaryPillow
Given that there isn't much of a difference between the true mountain bike and the race bike, the diminishing return is astounding.
The main reason to get a race bike isn't speed then I presume? Or rather, race bikes are only for those who need to squeeze every ounce of speed (eg. a racer).
A commute may not necessarily be the best comparison between the various types, IMHO. Stop lights, stop signs, dodging traffic, etc are all going to be significant equalizers. If you've got a nice relatively open stretch of pavement, the difference is going to be quite a bit greater.
The biggest difference would be the raw effort required. All else being equal, the roadie is going to have a lot more gas left in the tank than their counterpart on the full-squish mountain bike, once they get to the finish line.