On average athletes who visit A2 Wind Tunnel for aerodynamic tuning will reduce their drag by 10%
This means if you are expending 300 watts to overcome aero drag we may save you 30 watts or more in one session.
2 hour session ≈ $1000 ≈ 30 watts
Most athletes spend well over $1000 upgrading equipment that may only save a couple watts over your older equipment.
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We have a 2 hour minimum time booking in the tunnel. Booking a 2 hour test session will yield the most comprehensive test, as we can try a wide range of position adjustments and equipment to find your optimal aero setup. However if you would like to fit 2 riders in to the 2 hour minimum (1 hour per rider) this can be accomplished at a basic level. If you are interested in this option we recommend booking a 3 hour session for 2 riders as it normally takes at least 1.5 hours per rider for a standard test. Your time is not limited to the amount of time you book. We schedule a buffer so any additional time you may need will be available and charged by the minute.
Athletes who plan to have A2 contact recommended coaches should book about a month in advance to ensure the date you would like to test on will have an open slot at the tunnel and to give time to synchronize with the coach.
Athletes who plan on bringing their own coach or coming alone can usually get in the same week if your schedule is flexible. However if you have a specific date in mind we recommend booking 2 to 4 weeks in advance.
You will need to bring everything as you race (gear, helmets, wheels, bottles, etc..). Also, if your bike came with special spacers or bolts, be sure and bring those as well so changes can be made to the bike as needed. We have a wide range of aero helmets and sets of wheels at the tunnel, a list of our helmets, wheels, and bars can be found by clicking this link. If you are at all interested in new bars we have aero bars on hand but please ask about this before the test as you might need to have your cables removed so the process is simplified for us to make bar changes in a timely fashion. Please talk to us before you have this done.
Yes! Please Include your own name and date of test.
Example:
John Doe 12/26
A2 Wind Tunnel
117 Godspeed Ln
Mooresville NC 28115
YES! We have a wide selection of helmets, some wheels, and a small assortment of bottles and bars athletes may use for testing. Click this link for a full list of helmets, wheels, and bars. If you are at all interested in new bars we have aero bars on hand but please ask about this before the test as you might need to have your cables removed so the process is simplified for us to make bar changes in a timely fashion. Please talk to us before you have this done.
In the wind tunnel we will rotate your bike to change it's angle of attack. We refer to this as Yaw. By doing this we are able to simulate the effects of crosswinds. In these conditions you and your bike will perform differently than in no wind riding conditions. To find out more about yaw and how it effects you follow this link to an informative slowtwitch article.
In order to mount your bike in the tunnel we will remove your standard wheel skewers and replace them with our adapterskewers. Our skewers allow us to quickly and easily mount your bicycle in the wind tunnel. Our skewers adapters will attach to a set of front and rear wheel vertical struts that will keep your bicycle standing in the proper position and your wheels resting on rollers which allow you to pedal in the tunnel. As you pedal a computrainer will provide resistance. A belt running from the rear wheel roller to the front roller will spin your front wheel at the same speed as the rear. These struts and wheels rollers are all mounted to one plate. By measuring the forces on the plate we are able to see all of the wind forces acting on you and your bike.
Upon your arrival we will discuss your test goals, you will suit up, and we will prep your bike to install in the tunnel.
When we are ready to begin we will install your bike in the tunnel and give you some final instructions. The most significant of these being that it is imperitive that you keep a constant position during each run, and that you repeat that position every run, excluding any position changes we implement. The reason for this being that any change in position including head position, hand position on the bars, or your position on the saddle, can effect your data and it will be more difficult for us to determine the effect of the changes we implemented we are attempting to evaluate. We have several cameras in the tunnel we can use to monitor your position. We can project the same camera angles on the tunnel floor so that you have visual feedback of your position consistancy.
During each run you will be pedaling your bike. Our rig is designed so that your pedaling will also drive the front wheel. We will ask you to use half to three quarters of your normal effort. We need you to exert enough effort to put you in your true position, but not so much effort as to wear you out and compromise your ability to maintain a consistant position later in your test.
We will implement one change at a time so that we can isolate and evaluate each change seperately. Each run typically takes about 5 minutes to test. Typical changes include: stack, reach, extension angle, elbow pad width, helmets (we have a wide selection of helmets for you to evaluate listed here), head position, hydration, nutrition, electronics, textiles, and wheels.
Once testing is complete the tunnel operator will briefly go over your results with you. You will receive a cd containing your data results and pictures of each run before leaving the tunnel.
Your results will be displayed in an Excel sheet. Each run change will be labelled with a description (descriptions in the example are generic, yours will be specific). If there is any confusion with the run descriptions, our automated system takes photos of each run that you may refer to later. Drag numbers will be displayed in Drag Coeffient (Cd), Drag Coefficient x Area (CdA), Grams, and Watts. Results, and how to read the data file will be explained to you once the test is complete. You can download an example sheet by clicking the picture below.
There are 2 changing rooms at the tunnel. We also have a shower for athletes to relax and clean up after the testing is completed. We do not provide a towel, soap, or shampoo, so please bring any shower supplies you may need.
A cancellation fee will be assessed for cancellations with less than a 7 day advance notice.The charge for cancelling 4 hours or less of scheduled tunnel time will be $250. The charge for cancelling more than 4 hours of scheduled tunnel time will be $500 per day of cancelled tunnel time.
Manufacturers can usually get in the same week if your schedule is very flexible. However if you have a specific date in mind we recommend booking 2 to 4 weeks in advance.
If you would like to send us your products to test for you, you can send them right away and we will test them on our next available date, which is usually within a week of receipt. We have a telepresence robot if you would like to be a part of the test from your home or office.
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We have a 2 hour minimum time booking in the tunnel. Installing your product in the tunnel should take under 5 minutes. When we are ready to proceed we will take a 20 second wind off zero or tare, so that we can isolate aero forces from static forces. The tunnel only takes 10-20 seconds to come up to speed. At that point to determine how much time you will need you will need to determine a yaw schedule. All yaw angles will be tested in one wind on run unless otherwise requested. Our yaw table is capable of doing plus or minues 25° at as little as 0.1° increments. If you are testing a symmetric wheel it is unlikely you will need to yaw in both positive and negative. Each yaw angle takes approximately 1 minutes to rotate, stabilize, and collect two 22 second averages. At that point the fans will be shut off for a model change. This takes 5-10 seconds. Alot time for model changes. Your time is not limited to the amount of time you book. We schedule a buffer so any additional time you may need will be available and charged by the minute.
You will need to bring everything you need for testing. We do have some bicycle tools but recommend bringing your own to ensure you have the tools you need. We have pumps and compressed air. Generally we recommend bringing competitor's products for comparison. We do have wheels, helmets, and a few frames on site, but they are property of their respective manufacturer and on loan to A2 with the agreement that they will only be used for athlete's testing to evaluate for purchase.
Yes! We recommend shipping with an expected delivery date at least several days in advance of testing. Because of a same day as testing delivery multiple shipments have been received after the test the same day or later. Please Include your own name and date of test.
Example:
John Doe 12/26
A2 Wind Tunnel
117 Godspeed Ln
Mooresville NC 28115
No. You will need to bring everything to be tested. Generally we recommend bringing competitor's products for comparison. We do have wheels, helmets, and a few frames on site, but they are property of their respective manufacturer and on loan to A2 with the agreement that they will only be used for athlete's testing to evaluate for purchase.
Our yaw table is capable of rotating to positive or negative 25° with 0° degrees being pointed straight into the wind at as little as 0.1° increments.
Your results will be displayed in an Excel sheet. Each run change will be labelled with a description (descriptions in the example are generic, yours will be specific). If there is any confusion with the run descriptions, our automated system takes photos of each run that you may refer to later. Drag numbers will be displayed in Drag Coeffient (Cd), Drag Coefficient x Area (CdA), Grams, and Watts. You can download an example sheet by clicking the picture below.
Yes. We have 6 static camera angles. We will monitor the athlete position from live video feeds in the control room. These feeds can also be projected onto the tunnel floor with an outline for the athlete's own visual reference during testing. Our system also takes a set of photos from each angle at the start of each data capture. These photos can easily be compared between runs to evaluate consistancy.
There are 2 changing rooms at the tunnel. We also have a shower for athletes to relax and clean up after the testing is completed. We do not provide a towel, soap, or shampoo, so please bring any shower supplies you may need.
In order to mount your bike or wheel in the tunnel we will remove your standard wheel skewers and replace them with our adapter skewers. Our skewers adapters will attach to a set of front and rear wheel vertical struts that will keep your bicycle standing in the proper position and your wheels resting on rollers which allow you to pedal in the tunnel. Rear struts are removed from the rig for single wheel testing. In the case of bike and wheel alone testing a motor will drive the wheel rollers which will spin your wheels. With an athlete in place they will pedal and a computrainer will provide resistance. A belt running from the rear wheel roller to the front roller will allow your athlete to drive the front wheel at the same speed as the rear. These struts and wheels rollers are all mounted to one plate below the main surface. By measuring the forces on the plate we are able to see all of the wind forces acting on you and your bike.
Typically bicycle testing is done at 30 miles per hour. The tunnel is capable of wind speeds from 0 to 85 miles per hour. We do not recommend testing at wind speeds less than 30 miles per hour due to the low signal to noise ratio. Force data can easily be scaled to any wind speed on your data sheet (refer to "What will my results look like")
Yes. We have a smoke wand at the tunnel. There is no additional fee but smoke runs are billable time. During smoke testing the tunnel operator will operate the smoke wand from inside the tunnel. We recommend bringing your own camera(s) to document smoke testing from inside the tunnel. No force data will be measured during smoke testing due to the personnel presence in the tunnel affecting flow and pressure fields.
Photos of each run will be taken from 6 static camera angles during testing. We will be able to watch a live feed of all 6 angles from the control room during testing. However these cameras are used for visual reference and are not high quality so we recommend bringing your own camera(s) for marketing material.
The tunnel resolution is better than .001 Drag Coefficient; repeatability is based on the resolution plus the stability/repeatability of the flow field surrounding the bluff body. When using an athlete repeatability will be limited to the athlet's ability to produce a consistant position. In the case of bike or wheel alone testing Drag Coefficient repeatability has historically been around .001 to .003 Or roughly 2-8 grams at 30mph.
Before each test we take a wind off zero of static loads so we may isolate aero loads from static loads. We do not however provide a wind on zero that may be used to subtract aero loads on the rig alone from total aero loads. We can include an empty rig test in your time at the tunnel. However we do not recommend subtracting empty rig aero loads from your total loads as these results will artificially skew your data to appear lower than reality.
Yes. Bike and wheel alone testing will make use of our motorized wheel rollers.
Yes. We recommend testing with spinning wheels in all bicycle testing. During athlete testing the athlete will pedal and a drive belt between the front and rear wheel rollers will allow the athlete to drive the front wheel at the same speed as the rear wheel. For bike and wheel alone testing our wheel rollers are motorized and will spin your wheels.
Our tunnel operator can provide you with assistance in advance with developing your test procedure and answering general questions during testing. However design consultation is not provided.