How much faster is that new aero bike?

[vespasianus]

Originally Posted by EB

Wait - to be clear - the basis of the comparison didn't have aero wheels or an aero handlebar? And 20 of the 25 watts are from those two items? If that's the case this sounds more like an argument against modern integrated aero frames.

lol. I assume that is without a rider? Put a rider on that bike and with the same wheels, there would be no statistical difference in any bike.

[KonaSS]

Originally Posted by EB

Wait - to be clear - the basis of the comparison didn't have aero wheels or an aero handlebar? And 20 of the 25 watts are from those two items? If that's the case this sounds more like an argument against modern integrated aero frames.

The 20-25 watts from wheels and handlebar is a conjecture from fa63. I don't believe this was tested in the article. Not saying those aren't significant contributors, but they weren't isolated and tested in the wind tunnel.

[KonaSS]

Originally Posted by vespasianus

lol. I assume that is without a rider? Put a rider on that bike and with the same wheels, there would be no statistical difference in any bike.

If you read the article or even the thread, you would know that the numbers we have been talking is with a rider. And even one of the new superbikes (the Look) with aero wheels was statistically slower than the others. So of course adding aero wheels and bars to any bike would close the gap, but not all of it.

Weirdly, when things are designed to be more aero, it appears like they are. Not that hard to believe. Now, does performance gap of whatever your current bike is matter to you? That is for each individual to decide.

[Nomadmax]

My question is, if the aero thing starts to pay dividends @ X mph (say 25mph for instance), does it it work the same riding 15mph into 10mph block headwind?

[John H.]

I believe these estimates as to how fast modern aero bikes are- but I also know.
1.) Position matters most. If you can't achieve a good aero position, the bike is not going to make you into a rock star.
2.) Aero is the sum of everything. Rider position, clothing, helmet, socks, shoes, bike, bars, wheels, tires, and other details.
3.) Things like fast tires, ideal tire width, ideal tire pressure, optimized and clean drivetrain also matter.

So it depends on where your needs sit on the spectrum as to whether an aero frame matters or not.

[tv_vt]

Have not seen any mention of aero helmet in this thread, although that article mentioned that piece of kit having a huge effect. Also, clothing - hate to say it, but my Rapha wool blend jersey is slower than a skin tight jersey. I can almost say that jersey effect is noticeable to me, too.

So: helmet, wheels, jersey. Add maybe shoe covers and you're rocking pretty good, I'd think. Get your position good on the bike, shave the legs (and arms?), and those round tubes and exposed cables on your Pegoretti/Kirk/Sachs won't be a problem at all.

Oh, yeah - forgot about socks!

[GregL]

Originally Posted by John H.

I believe these estimates as to how fast modern aero bikes are- but I also know.
1.) Position matters most. If you can't achieve a good aero position, the bike is not going to make you into a rock star.
2.) Aero is the sum of everything. Rider position, clothing, helmet, socks, shoes, bike, bars, wheels, tires, and other details.
3.) Things like fast tires, ideal tire width, ideal tire pressure, optimized and clean drivetrain also matter.

So it depends on where your needs sit on the spectrum as to whether an aero frame matters or not.

^^^Excellent assessment ^^^ I’ll opine that if you’re road (or fast gravel) racing, aero frames are fast becoming a necessity. I’ve gone all in on aero and efficiency for racing (pretty much everything in your list above). The marginal gains do add up.

Greg

[Spdntrxi]

I'm all in aero for the road.

Somewhat fighting it for gravel.. although I do have deep wheel option (Enve4.5) and Enve AR handlebars and aero stem.

I like my frame for gravel (Parlee Z0XD)

[fa63]

They have laser guides in the tunnel, so they were able to have the rider move his hand/wrists around on the bars and maintain a consistent position.

Originally Posted by lorenbike

Did they control for handlebar width? It seems like modern bikes are more narrow at the hoods like 36-38cm and flare outwards, compared to standard bars ten years ago that range from 40-44cm at the hoods.

[Baron Blubba]

My experiences riding the same routes dozens of times on separate bikes ranging from relative clunkers to modern top of the line aero bikes is that the differences when riding in real life are greatly exaggerated. Both aero and weight.

[CAAD]

Originally Posted by fignon's barber

Exactly. I don't understand all the outrage over internal cables and hoses, especially if the bike has discs and electronic shifting.

Exactly. These days 2 internal hydro hoses essentially never need to be messed with. Wireless shifting, wireless.

When the Trek Madone first came to market with fully integrated mechanical shifting and mechanical brakes, they were nightmare to build and keep running smooth.

[Mark McM]

Originally Posted by Nomadmax

My question is, if the aero thing starts to pay dividends @ X mph (say 25mph for instance), does it it work the same riding 15mph into 10mph block headwind?

For the first part of the question, aerodynamic drag reductions matter at all speeds (it's not like they suddenly matter above some threshold speed), but at the same time, they matter more at higher speeds.

For the second part of the question, the magnitude of aerodrag force depends on the apparent wind speed, which is a combination of the rider motion and the atmospheric wind. The aerodrag force on a rider is the same when riding 25 mph in still air as it is when riding 15 mph into a 10 mph headwind.*

Also keep in mind that power is the product of speed times force. Even if the aerodrag when riding at 15 mph into a 10 mph headwind was the same as when riding at 25mph into still air, the headwind case would take only 60% as much drive power, because the rider is applying the same drive force to the road but at only 60% of the speed. If the rider applied the same power as it took to ride 25 mph into still air, they'd actually be going faster than 15 mph into the 10 mph wind - maybe more like 18 mph. Which means that the apparent wind will be higher than 25 mph, which in turn means that aerodynamics becomes more important in the headwind case.



*Actually, this isn't quite true. Wind speed diminishes closer to the ground - if the wind is 10 mph at 10 ft above the ground, it will be lower at 5 feet above the ground, and lower still at 2 ft,a and even lower at 1 ft above the ground. So when riding into the wind, the apparent wind will be lower on the legs and feet than at the head and torso, and the total aerodrag force when riding at 15 mph into a 10 mph will actually be a bit lower than when riding at 25 mph into still air.

[fa63]

I don't know how fast your typical rides are, but power is proportional to speed cubed, so if you are averaging 16 mph instead of 25 mph, then the difference is only (16/25)^3 = 0.26 (26%) of 25 Watts, which would be 6.5 Watts. Then it would indeed be hardly noticeable.

Originally Posted by Baron Blubba

My experiences riding the same routes dozens of times on separate bikes ranging from relative clunkers to modern top of the line aero bikes is that the differences when riding in real life are greatly exaggerated. Both aero and weight.

[marciero]

Originally Posted by Mark McM

Also keep in mind that power is the product of speed times force. Even if the aerodrag when riding at 15 mph into a 10 mph headwind was the same as when riding at 25mph into still air, the headwind case would take only 60% as much drive power, because the rider is applying the same drive force to the road but at only 60% of the speed.

For a given pedal force, a lower gear results in greater force at the road. In the headwind case, it would be possible for the rider to gear down such that they apply the same pedal force at the same cadence as in the non headwind case, but with a greater force at the road. Are they not doing the same work in either case and hence same power? Work per time turning the pedals, or moving the bike, is the same.

[fa63]

The power required to overcome rolling resistance is proportional to "ground speed", whereas the power required to overcome aerodynamic drag is proportional to "air speed" which includes the effects of the headwind.

Originally Posted by marciero

For a given pedal force, a lower gear results in greater force at the road. In the headwind case, it would be possible for the rider to gear down such that they apply the same pedal force at the same cadence as in the non headwind case, but with a greater force at the road. Are they not doing the same work in either case and hence same power? Work per time turning the pedals, or moving the bike, is the same.