riccofiori

bbbean 

Answer the following questions:

1) How did it ride when you went to the store and test rode it?
2) How did it compare to the other bikes you test rode?
3) Do you spend more time riding in the wind or riding up climbs?
4) Do you like to go fast?
5) Can you afford the bike?

Aero bikes are more aero than non aero bikes. Whether that is worth the price of admission is entirely up to you.

From a purely subjective point of view, I absolutely love my aero road bike (Giant Propel). Its fast, responsive, comfortable, and very close in weight to a similarly equipped TCR. My next bike will be an aero road bike as well.

One more note - the whole "is this worthwhile if you don't race" question is ridiculous. It's a bicycle. You ride it because you enjoy riding it. If you enjoy going fast, it doesn't matter whether you ever pin on a number. Buy the bike that makes you happy.

pm124

Yup! If you can put out 200W, it will make a difference. At 200W, a racing recumbent is about 20% faster than a road bike with the rider in an aero position on a flat. At 300W, this advantage increases to 30%. Check out this aero calculator. It also has data for tri bikes relative to road bikes. Note that this doesn't make much of a difference in a peloton, and a recumbent isn't exactly suited for that kind of riding.

ridesoldtrek

HTupolev

You can rotate an object in a wind tunnel to measure its drag at various wind yaw angles, yes. This is typically what's being shown in two-dimensional drag graphs: drag versus incident wind angle.

RChung

I do. You have made an incorrect guess.

Maelochs

All 6hings being equal---if the bike rides and handles well enough to suit a given rider---the more aero the frame, the faster. it gets into the same realm as lightness, though---at what point does it make no noticeable difference to a rider without instrumentation who is not competiing.

Which was where this thread started.

Answer---an aero bike is perfect if you want one. if you are looking for a new bike and find an aero frame and like the ride ... great, you will be marginally faster for less energy. if that matters, the deal is sealed. People who don' khnow what kind of riding they like ... hard to suggest any specific style of bike. people who do know, probably won't have to ask.

For most, the answer to whether it makes a difference is "What's a 'difference' to you?" and the answer to whether it's worth it is "Only you can decide."

I think the pros and cons and sidelights and so forth have been pretty well laid out here, well done to those who participated positively.

Seattle Forrest

That's a damned lie, and I'd appreciate it if you stopped trying to spread this awful Yankee rumor that I have weaknesses.

riccofiori

Seattle Forrest

cyclintom

If your average speed is below 20 mph don't bother with the crap published about speed.

Abe_Froman

Erm. Even the stuff regarding 18mph speeds? Something with the math here isnt making sense for me.

ridesoldtrek

yukiinu

For the average rider to spend a thousand dollars to take a pound off their bike, or to decrease drag by a little bit with aero, which is of little use or even noticeable ro the average rider, is I think a waste of money. Why spend thousands of dollars to decrease bike weight and some drag, when you can decrease your body weight, at no cost, and go just as fast or faster on a medium priced and weight bike. For the average rider to pay thousands of dollars for a super lite and aero bike, is like a person spending a million dollars on a 1,000 horse power Italian luxery sports car, it makes the driver/bike rider feel special, but the race setup is of no real use to the average driver/bike rider.

noodle soup

I'm already at my low/healthy weight.

Losing weight will likely result in a loss of power. I'm much faster now, than when I weighed 25lbs less.

RChung

Hmmm. Despite your attempt to move the goalposts, your *exact* words were: "Does anyone here know exactly how the wind tunnel testing is done? Does it account for a mix of headwinds and crosswinds (as one would encounter in actual ‘field’ conditions? I would guess no, unless the cycling industry has agreed on a standardized complement of test conditions to allow accurate comparisons."

Wind tunnel testing done by bike manufacturers includes a "yaw sweep" to measure drag at various angles, and that doesn't at all require an industry standard -- yaw sweeps have been done for years even without a formal industry standard.

That said, for various reasons related to practicality, there are de facto standards. There are actually only a handful of low-speed wind tunnels that have been used for testing full-size bicycle components (the practical issues are that most wind tunnels are designed for testing airplanes or jets or cars at much higher speed than the speeds used for bikes and bike components. That means they often use scale models in small tunnels or else "full-size" tunnels that are turned for speeds much higher than cycling speeds -- so their sensors aren't appropriate for bike speeds). In addition, because there are so few full-size low-speed tunnels that are appropriate for measuring bikes and bicycle components, it's hard to schedule large blocks of time in only one tunnel, so manufacturers will usually work with a couple of different tunnels. So they've worked with the tunnel operators to determine protocols that are "portable" across the tunnels they use so they can get the same (or close to the same) readings. Over time, even if there is no official industry standard, there have developed de facto standards in the yaw sweeps (for example, the yaw sweeps are usually bi-directional because of hysteresis effects, usually at 2 deg. intervals, with usually a "settling in" interval for each yaw angle that depends on the specific tunnel and sensors so that the readings can stabilize). Specialized is the only major bike manufacturer that has its own tunnel, but it's only a few years old so they used to use other tunnels until recently, and they "ported over" the same protocols that they used before.

If you're familiar with how the drag is measured (and it's clear from your statement that you're not, but I'm trying to be generous), it's typically measured in Newtons for force. No one speaks Newtons of force, so by convention (and the reason for this particular convention is kinda funny) the drag for bike components is most commonly reported as "grams" of drag at an airspeed of 30 mph, even though it's weird to mix "grams" and "mph." Since you're not familiar with this, this doesn't mean the tunnel airspeed for the tests is 30 mph. The tunnel operators are smart enough to know algebra and adjust the drag force to the equivalent of 30 mph no matter what the actual air speed is. Another thing you probably hadn't thought about is that if a test is done at an airspeed of 30 mph at zero yaw, when you rotate the object in the flow the the airspeed in the direction the bike is pointing is no longer 30 mph. Once again, the tunnel operators are smart enough to know algebra so they account for that.

Up above I said that the protocols are adjusted by the tunnel operators so you can get the same (or mostly the same) readings at all tunnels. It turns out that there are "tunnel-specific" effects that can bias the readings a little (there are blockage effects and floor effects and so on) so a few manufacturers have a standard object that they carry with them from tunnel to tunnel so they can tune the readings across tunnels. Cervelo famously had a mannequin that they carried between tunnels, but less well-known is that they had a reference frame too. In any event, aerodynamicists have moved between different manufacturers and the tunnel operators work with all manufacturers so the tunnel-specific biases are pretty well-known within the industry.

Finally, although there are de facto standards for the testing protocols, each manufacturer can report their results in their own way to their own audience. So if they do well at zero yaw but not at 5 deg, they tend to report just the zero yaw results. A few manufacturers (a few bike manufacturers and a few wheel manufacturers) have started to release the full yaw sweep data (though standardized to the afore-mentioned 30 mph), so you can compare those if you're motivated enough to do so. That you had such a strong opinion even in the absence of knowledge is a reasonable clue that you're not among this group of people. Nonetheless, a handful of manufacturers have started reporting "weighted" drag where the weighting kernel is based on a distribution of yaw angles at a given (ground) speed. With the proliferation of newly available yaw sensors we can expect that eventually more manufacturers will be reporting yaw-weighted drag, but the kernel will be buried in the fine print so people like you will assume that it isn't done at all. That's (sadly) understandable. Lots of people have such a high opinion of themselves that they think if they can't imagine how something is done then that's reasonable evidence that no one else could possibly have thought of it either. You would have done better to stop at your first two questions ("Does anyone here know ..." and "Does it account for ..." ) and left off your dismissive opinion.

MyTi

Abe_Froman

You don't have many friends, do you?

The irony/hypocrisy of watching someone write this:

...in the same post as the rest of the bits I bolded is almost too funny/painful for me to read.

wphamilton

The funny thing about the wind tunnel question, and it's topical in a way, is that the testing is for design. For improving the design, and not particularly for consumers to compare finished products. Sure it makes some nice ad copy, and scientific-looking filler for a reviewer but a little common sense here: would any rational frame maker devote the time and resources for wind tunnel testing merely to compare products for a marketing claim? When you could accomplish the exact same thing, and more believably by, for example, simply putting a sports celebrity on it and filming his reaction?

So there isn't much incentive for them to institute an "industry standard" for aero measurements, and since consumers don't get to see ALL of the data, nor fully understand it if we did, the standards wouldn't be of much use to us.

The reason it ties in here is that you could tell me "3% less frame drag at +/- 7° yaw 40kph" and nobody but the design team really cares. Tell me that I'm 3% faster because of "less drag", now we're talking! Is there any "real advantage"? Well the wind tunnel says yes there is *something* but we're all empiricists here. Is it "real" enough to experience with our own senses?

AlmostTrick

Someone in our Saturday "Social group ride" showed up with an aero bike that had little 'wings' behind the head tube that would flap out when he turned the bars. I wonder how much drag reduction that's worth. It was fun to see, marvel at, and talk about though. It's kind of amazing to me that we have stuff like this available to us.

RChung

So what you're saying is, my efficient way of just giving short answers and telling people to read and research the full info is looking better and better.

RChung

Right. It's also why it's been handy to have a way to measure drag parameters on your own, because the things you're interested in aren't always aligned with the things the manufacturers are interested in.

Abe_Froman

Yea. It does seem your short and dismissive responses were somehow less insulting.

Sorry about rocking that boat...

Maelochs

Some guy showed up with some wood and matches, a couple people brought lighter fluid, some guy had a gas can in his car, a few people had some old newspapers, some more people brought some scrap lumber, some guy brought a Bic lighter .... now people got burned and people are upset.

This is where the "Does saving weight matter" threads end up too.

Hermes