romulusmagnus wrote:
I'm curious what you think of the aero gravel bike concept...I don't think it's a good idea to ignore aerodynamics for most ANY bike application...but, depending on the intended use, other performance features may take precedence over ultimate aerodynamics. For pure road race/TT/Tri machines, that's not the case...but for "adventure bikes", it may well be...just as it is for MTBs.
One of the cool things about a bike with separate braking discs is that, as long as frame clearances allow, one can run a wide range of wheel sizes and tires and not materially change the "working geometry" of the bike. In that sense, if the intended use of a "gravel" or "adventure" bike includes the owner wanting to sometimes run 700C wheels with tires up to 30-31mm wide, or 26" or 650C wheels with MTB tires on them, then using separate braking disc wheels is a great way to accomplish that.
So, if going in you know that what I describe above is the intended use, then by all means separate braking discs make sense since they facilitate that capability. It would be hard to do that with a braking surface on the rim.
Now then, having put together my own cobbled-together version of an "adventure bike" (using a 26" hardtail MTB frame as the basis) I can tell you that if one ignores aerodynamics and then tries to use that sort of bike for fast road use, you'll be surprised at how "slow" that type of rig can be when trying to go fast. As an example, when I finally acquired my 700C wheels for my "adventure bike" (I initially built it up with some 26" MTB wheels I had already), I decided to put some fast road tires/latex tubes on the new wheels and take it on the local Sunday group ride, just to see how it would fare. To be specific, the new wheels are American Classic 101s (30mm deep aluminum), with 32 round spokes each.
In short, between the wheels (large number of round spokes, braking discs) and the large aluminum frame tubes on the bike, there was enough added aero drag that I was dropped on the flats during a ride I normally EASILY sit in on, and sometimes "play" at the front on when I'm on my normal road bike. That was depressing...I couldn't even hold a wheel! :-/
So...if the intent of the "aero adventure bike" is to allow the rider to more easily "play" in more road-race-like situations, then it makes perfect sense. It's not going to be as good as a pure roadie for the purpose, but at least you might not get dropped ;-)
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