Questions tagged [aerodynamics]

Questions relating to a bicycle's ability to efficient move through the air.

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19
votes
4answers
6k views

What is a “gram” of drag?

Bike components or upgrades are sometimes quoted as saving some number of "grams" of drag. How can a gram, a unit of mass, be used to quantify drag, which is a force? And for extra credit, why is ...
4
votes
3answers
1k views

How much aerodynamic drag does each component contribute?

Obviously numbers will vary based on the specific bike, but what are some approximations of the drag contribution of individual components in a typical (non-aero) road bike? I have read in many ...
0
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0answers
96 views

Is there a reason that velomobiles aren't made in a prone design?

So I just recently began looking at making my own velomobile and I designed a prone position reverse trike. I was having trouble converting my design into real dimensions and decided to look and see ...
3
votes
2answers
461 views

Effects of longer and higher stem on rider position/comfort and handling

My first road bike, and the bars feel a little low and a little close. What would be the effects of switching to a stem that is 10-20mm longer, and either the same angle so the bars are slightly ...
4
votes
1answer
98 views

Independent ranking of bicycles aerodynamics

Are there any scientific and independent evaluations of different bicycles from an aerodynamics perspective?
3
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1answer
185 views

Road bike drag decrease with bulky backback

I'm about to increase my daily commute from 5 km each way to 10 km each way. I've been using a MTB converted to a commuter for years. Given the extra distance, regular evening head wind, and aging ...
1
vote
2answers
230 views

How close do riders follow their wheel/attack

How close do peloton riders typically and strategically follow each other's wheel/attack? Also, how is this distance manipulated in order to allow for strategic movements or a more aerodynamic ride.
3
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3answers
356 views

Is there any benefit to riders on the front of a paceline? [duplicate]

You can save a lot on air resistance by drafting a rider closely, i.e. riding close to their rear wheel. What about the rider in front? Is there a benefit, a loss, or is there no difference? Edit - ...
0
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2answers
433 views

How much resistance comes from each part of a bicycle? [closed]

How does one decide which part of a bicycle is the best candidate to upgrade or tune if the goal is higher speed for the same energy? For example, should one upgrade wheels, or tyres, or change to ...
18
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5answers
5k views

Why are road bikes (not time trial bikes) used in many triathlons?

I've been watching triathlon videos lately and I couldn't help but notice that, with the exception of Ironman Competitions, only road bikes and not time trial bikes are being used. Is there any reason ...
1
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2answers
414 views

Does fitting mudguards / fenders improve aerodynamics?

Since the tops of the wheels are moving at twice the speed of the bike, you would think that covering them up would make quite a bit of difference to the drag coefficient, particularly the front wheel....
11
votes
5answers
9k views

Why aren't road bicycle wheels tiny?

My understanding is that air resistance is where most of the pedal power goes to at high speeds, and that this is a concern not least for the wheels: What you pay for in a road bike wheel is ...
2
votes
1answer
156 views

Aero bike considerations for purchase

I am trying to decide between aero bikes from two different brands. What are some of the things I should think about when comparing these two (or any other) aero bikes?
6
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3answers
1k views

What is the drag / power lost to a safety flag?

I have a recumbent bike that has a safety flag on the top of a thin pole, so it flutters around higher than and after my head. How much power am I losing to this flag that could be used to power my ...
5
votes
2answers
437 views

What's the best way to shield a rider from the wind in a group (most aero position in the group)?

Yesterday I caught up with a much stronger rider who was struggling with an injury but really wanted to finish. Moral support aside, we tried to get him on my wheel on the flats (which happened to ...
1
vote
1answer
634 views

Can hybrid bikes be as fast as cyclocross bikes if we use an aero position instead?

Can hybrid bikes be as fast as cyclocross bikes if we use an aero position instead? There's quite a lot in common for both bikes. People claim that CX bikes are faster. It seems like the main reason ...
2
votes
4answers
1k views

Thoughts about tri bar / trekking bar on hybrid bicycle

I have an hybrid bicycle Firefox Rapide 21S. I ride regularly around 40 KM. In headwind I feel like I should be in aero position so sometimes I put my elbows on my handlebar and it helps to reduce ...
4
votes
1answer
3k views

Climbing or aero bike for a light rider?

What is the better choice for a lightweight rider (173cm - 48 kg), lightweight climbing bike to get even bigger edge when climbing, or an aero bike to catch up the speed in the flat road? Obviously I ...
4
votes
2answers
401 views

CdA of a bike without rider

This question at aviation.se got me calculating the acceleration of a bike strapped to the outside of a plane if the straps broke. As you do. I couldn't find a figure for CdA of a bike without rider ...
2
votes
1answer
784 views

How much better are aerodynamics between a vintage road bike and a top of the line aerobike?

(Just up front: (1) All comparisons made keeping all other factors equal! (2) I know this is a really hard comparison, but there seems to be virtually nothing canonical on here or the rest of google, ...
0
votes
1answer
103 views

Should i upgrade from Skultura 400D with 105 to giant tcr advanced with ultegra di2? [closed]

I have had the merida skultura 400d and have ridden around 1100kms. Would there be any value in getting giant tcr advanced pro disc or the propel advanced pro? My rides are generally 80kms a week ...
1
vote
6answers
1k views

What position of saddle is best?

Almost all cyclists who ride road bikes set the seat so high, and when they're in the drops their body can be almost parallel with the road, reducing air resistance. However,their legs can't reach the ...
6
votes
1answer
1k views

What's more aerodynamic on flat bars: backpack or pannier?

I'm surprised this hasn't been asked before, but as a general rule, is a single rear pannier or a backpack (of similar sizes) more aerodynamic on a hybrid or MTB? Even on flat bars drag is much more ...
5
votes
4answers
5k views

Aero bike vs climbing bike for running in Crits

I'm considering building a road bike and getting into running Crits this Summer and I'm unsure as to go with an Aero bike or a climbing (lightweight) bike. Based on my general understanding, when not ...
6
votes
1answer
2k views

What is the average CdA to Weight relationship of a professional Road cyclist?

As Body mass increases so does its volume resulting in a higher CdA causing more drag. However CdA does not increase linearly with mass. Are there any posted weight and CdA comparisons out there for ...
2
votes
2answers
651 views

Why do deep section front wheels get pushed around in crosswinds?

If a bike with a deep front wheel or a front diskwheel were to receive crosswinds with a 90 degree yaw angle handling would not be affected since the pressure would be equally distributed among the ...
13
votes
1answer
331 views

Why do track bikes vary between events?

Watching the Olympics, I've noticed that track bikes seem to vary between events. For example, in the Keirin, all the riders have bikes with a solid/disc rear wheel and a front wheel that has a solid ...
11
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2answers
11k views

Aero Bars vs The Drops

On my road bike I am debating installing aero bars. Will I notice a significant measurable improvement in speed using aero bars vs being in the drops? I am looking for specific numbers here with ...
1
vote
1answer
324 views

How does hub diameter affect aerodynamics?

There is a lot of discussion out there about spoke, rim & tyre drag, but almost nothing concerning the aerodynamics of the hubs. What got me started on this is the fact that road hubs still have ...
7
votes
3answers
6k views

At what speed does Aerodynamics of a bike come into play?

Is a more aero bike more efficient than less aero bike at 10mph? At what speed does Aerodynamics affect your speed significantly. update: "The question is dealing with the minimum speed that a ...
2
votes
3answers
290 views

Can it be estimated when it would actually be beneficial to increase drag in tailwind?

Usually the advice for cycling is to try to be as aerodynamic as possible (like, reduce the surface exposed to the air in front of you) in order to decrease drag as it will cost less effort to ...
9
votes
1answer
982 views

Road Bikes: Aero vs. Traditional

On any given race within the pro peloton, the teams whose sponsors offer both aero and traditional frames (BMC, Trek, Canyon, etc) typically have a mix of riders on each style of frame, but the GC ...
2
votes
1answer
4k views

How can I move the saddle further forward?

Recently I bought a clip-on aero bar for my road bike and has been practicing aero position for triathlon. I read that moving the saddle forward could mimic the triathlon bike geometry. However, I ...
3
votes
3answers
3k views

What is the best aero position in a mountain bike?

I'm familiar with TT and road bikes with aero bars. However, I don't know what is the ideal aero position for a normal MTB (no aero bars). I did some search and found these pics. Hands on the middle ...
6
votes
5answers
2k views

Riding into a headwind faster than my top speed - how is it possible?

Recently we've had some pretty strong winds here -- today the weather forecast said 20mph gusting to 30mph, but a few weeks ago the gusts were supposedly over 40mph. The forecast direction was within ...
3
votes
2answers
163 views

Anti-aero resistance training jerseys?

Is there any manufacturer that makes specific anti-aero training jerseys for increased effort at lower speeds? Sort of like a braking parachute but more practical and subtle? My reason for asking is ...
8
votes
1answer
2k views

What is the difference between Time-Trial and Triathlon bikes?

Time-Trial and Triathlon bikes differ from normal road bikes in that they are designed for maximum efficiency when riding alone (not in a group). What, then, is the difference between them? Would ...
0
votes
1answer
375 views

Where does aero wheels noise come from?

One time I hear someone said, with satisfaction, that his aero wheels sound awesome. I wonder where does the noise come from, is it because you ride so fast the pushed air makes the noise or is it ...
2
votes
4answers
814 views

Does riding a cyclo cross bike carry a large aerodynamic penalty when compared to a road bike?

During club rides I find myself getting dropped by riders with the same weight and power but the main difference is that they are riding road bikes and I am on a cyclo cross bike (with road tyres and ...
1
vote
1answer
395 views

Why am I not seeing improvement in my bike split time?

My training went up significantly between half-iron events. There was improvement in the swim and run. But no improvement in the bike... In fact I could say I did worse because there was little ...
2
votes
1answer
2k views

How do I choose a light GPS device supporting Strava? [closed]

Up til now I have ridden with Strava running on my mobile phone sitting in a special mobile phone holder which sits up on my handlebars. Now I am looking for a better solution, both more aerodynamic ...
2
votes
1answer
142 views

Does hub diameter or hub size have a notice able effect on the aerodynamic performance of a wheel set?

If you were to change the rear hub on your hypothetical or real zipp 808 wheel set to a large diameter internal gear hub like a shimano alfine or a rohlhoff hub would there be a measure able aero ...
3
votes
3answers
1k views

What sort of bicycle helmet gives me better speed?

I am working to improve my segment times on Strava riding 10km to/from work. My average speed is 32 kmph, and over short segments (1km) I can set avg speed 44 kmph / max 49. Over the last year I ...
7
votes
1answer
417 views

Accurately replicating the resistance felt whilst riding via a resistance fan diy turbo trainer

If I were to build my own Lemond Revolution style turbo trainer (link below) could I use the air speed in meters/second^2 the rider is moving into as a good indicator of what type and size of fan to ...
1
vote
2answers
569 views

Cube Agree GTC - Tri-Bars

I have a Cube Agree GTC (2012), and I would like to buy some tri-bars for it. I've read that this model ( Although, on second thoughts, maybe this is a newer model...) has compatibility issues with ...
5
votes
2answers
2k views

Does group riding negate the aero benefit of deep rim wheels?

I've been weighing up some options over wheels and in doing my research I've noticed that rim depth may be a bigger factor than I had previously considered. On the one hand, shallow rims are typically ...
1
vote
1answer
195 views

Aerodynamic effect of drafter to the draftee [duplicate]

I thought I read somewhere something like having someone drafting behind also has effect to the rider in front. I wonder if it's true and would like to understand how does it work because it's quite ...
1
vote
1answer
1k views

Wheel performance in cross wind

I'm looking to buy a pair of Mavic Cosmic Carbone SLE or Mavic Ksyrium SLR. The Cosmic's are 50mm height, Ksyrium 25mm. I'll only be using the wheel for racing. How do they perform in cross wind. I'...
6
votes
1answer
861 views

quads feel over used while in an aero position

I typically ride on the hoods, but I've been working lately on a more aero position. When in the drops or using clip-on aero bars I find that my quads get fatigued much more than when I'm in a normal ...
13
votes
5answers
8k views

Are aerodynamic rims worth additional weight?

I was under the impression that reducing the weight of your wheels is important. However, I'm noticing that many of the extremely high-end aerodynamic rims are actually heavier than cheaper rims by ...