Originally Posted by
63rickert
In the classic era every bike was a gravel bike. The road turned to gravel and you kept racing. Or riding. Same bike was used for Paris-Roubaix and for Paris-Tours.
This might mean that a 10 or 20 year old bike is not classic enough. Go back 50 years and most bikes will take 32mm tires and still have a centimeter of clearance all around for mud and rocks to pass through. Youngest bike in my collection is 59 years old. It rides very well on gravel.
In the classic era, 42 gear inches was often times the easiest ratio spec'd. Just because things happened in the classic era doesnt mean they need to stay that way.
Gravel means different things depending on location, but I have 0 desire to ride my road bikes on any of my gravel rides. It simply isnt as comfortable or fun. Its been done in limited distances(a few miles) multiple times and every time ive done it, i think about how much more fun and faster I would be with my gravel bike. There is a measurable difference in comfort and stability.
You mention 32mm tires and these will be more comfortable than 23 or 25mm tires, but again, I have 0 desire to ride gravel on 32s. It simply wouldnt be fun(again, ive done it around me in limited amounts out of necessity).
A 40mm tire has the width to not deflect a bunch, and the volume to allow pressures to drop to reduce vibration and increase comfort. This all means more comfort, more speed, and less exhaustion.
In other areas, if 'gravel' means smooth hardpacked dirt, then sure a 32 tire will be great. Its very area specific for sure.