Originally Posted by
rapwithtom
Somewhere we recently discussed aero handlebars.
The upshot was that:
~80% of aero drag comes from the rider, leaving 20% for the bike.
From that discussion, and other reading, of the drag from the bike:
- both aero handlebars and aero wheels are significant areas to optimize/minimize drag
- Other things, like like aero seat posts and lowered seat stays, are comparatively small effects.
Hence, putting aero bars on a tarmac, along with aero wheels, gets a lot of the benefits of aero bikes.
This was my thought. When Trek came out with the aero Madone a lot of the claimed savings for the bike came just from the aero bar, sort of like Specialized saying 5 minutes from their whatever bike. Aero bars don't sail, though, like wheels do, so that savings won't multiply in serious crosswinds. I'm guessing that aero frames probably sail a bit. By sailing I'm talking about optimal situations like a strong cross-tailwind. I love tall wheels in those situations.
Another thought is how tall is your frame? I have about a 10 cm head tube, and some of it is obscured because my stem drops 3 cm from horizontal (so maybe 8 cm head tube exposed below bar?). Making 8 cm of vertical head tube aero-ish doesn't seem to make much sense. Making 20 cm of head tube on a taller frame, probably makes more sense.
A number of my teammates have the Madone. It's just a cool looking bike, and I'm a zero Trek fan. The bikes are reportedly good for long rides, short rides, etc. Comfy and responsive. I have no idea because they're all too tall for me to pedal around at all.
When I asked a bike tech guy/friend with extensive low speed wind tunnel experience about aero frames, he grinned. He said that, okay, fine, in a full on sprint it might be worth half a kph, maybe a kph. It put things in perspective. Wheels, for sure there's a difference, especially in optimal conditions (and basically zero benefit in a perfect headwind). But 1 mph is 1.5 feet per second, and if you're sprinting for 10 seconds (typical for me), that's 15 feet. Seeing as I've won and lost races by a foot or less, 15 feet for me could be the difference between winning and maybe 5th-10th. Even half that, 7.5 feet for a short sprint, that's significant. Long sprints are 20 seconds, and now you're talking some serious distance deltas.
Finally, aero stuff is always aero. Even if it's just worth 10w at break speeds, it's 10w you don't have to put down. Or 10w you can invest in speed.
Of course this makes me want to get the Bontrager aero bars, if they make a 120/80 x 38 cm, and the Bontrager aero road helmet. And a skinsuit. And...