Originally Posted by fujidon

I used to commute to work about 14 miles each way on my road bike. After I bought a mountain bike, I set it up with road tires just for the commute. I timed myself over multiple days and was surprised to find that while it was a little slower, the difference was much less than I expected.

Later, I bought a heavy fat tire touring bike (similar to a gravel bike) and started using that to commute. Again I timed myself over many trips and could not find a significant difference between a touring bike and a dedicated road bike.

I have a gravel bike now (Specialized Diverge). I plan to use it for touring. I pump the tires up to 60 psi for the road. I haven't timed it to get empirical data, but it does feel like it might be just the tiniest bit slower. A lot of that feeling is probably subjective since my riding position is different and the gravel bike is a little heavier.

Back to the point... if I could only have 1 bike, it would be a gravel bike because I think they're the "do-it-all" bikes and close enough to the speed of a dedicated road bike that most cyclists would never notice the difference.

A little bit of rant to follow:

I also happen to think that the whole concept of gravel bikes are mostly an invention of bike manufacturers to create demand for a niche product. Other than for competitive gravel cyclists, road bikes could be designed to fit 35c wheels (which many now are) and we could basically be turning our road bikes into gravel bikes just by swapping tires.