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Old 01-31-05, 03:11 AM   #1
tkehler
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Do fairings work?

Short question: is the hype true, re: fairings? Have you found that they've improved your speed or made your ride more pleasurable, or what?

I've been thinking about putting a small or medium sized one onto my EZ Speedster SWB.

Thanks.
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Old 01-31-05, 05:07 AM   #2
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The seem to work best on Tour Easy's. Vision did some tests with their SWBs and found little to no improvement, IIRC.
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Old 01-31-05, 07:14 AM   #3
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The determining factor for whether or not they help is what you do with the air after you punch a hole through it. As the air flows over the fairing, it speeds up. With a Vision, the air gets dumped off the fairing and hits the rider in the chest. The fairing actually induces a greater apparent headwind! OTOH, with an Easy Racer, the airflow falls to the sides and is channeled by the legs, around the rider. At the top of the fairing, the air is channeled by the rider's arms - again, past the rider. It's still pretty dirty airflow, and some still hits the rider's body; but it's better than riding bare. To clean the airflow up even further, a body sock is used to not only channel more air around the rider, but to help close off the turbulence at the back of the bike.

That's the theory. Will it help? It depends on your speed. Aerodynamics start coming into play at about 12 mph, but they don't become significant until 15-18 mph. I generally tell people that if they don't ride at 17 or 18 mph without the fairing, they won't see much gain with a fairing.

Since you're specifically asking about an EZ-Speedster (SWB), I'll say that a fairing *can* help, but it will have to be one that covers your feet and hands. I've looked at the commercial offerings, the decided I could get better performance by building my own out of coroplast. Pictured below is my Mark IV fairing on my V-Rex24. It helps about 2 mph at 20 mph (10%).
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Old 01-31-05, 12:54 PM   #4
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Quote:
Originally Posted by john riley
The seem to work best on Tour Easy's. Vision did some tests with their SWBs and found little to no improvement, IIRC.
....and other LWBs....

If you're speaking of the windtunnel test, it gave the Vision R40 (swb) a 1 mph boost at 20 mph (not accounting for any margin of error), so I guess it depends on how much you value small increments of a speed increase. I have one for my Rans V-2. Seems faster than my unfaired Stratus, but heck, there's other factors at play (frame stiffness, bottom bracket height) in my case.
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Old 01-31-05, 01:22 PM   #5
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Fairings are not going to do much for you if you can't habitually ride above 20mph.
The improvement in aerodynamics adds only a little bit in the 16-20mph range, but
as you approach or exceed 25mph the power needed drops more noticeably. Few
of us have an engine that is upto that amount of power output. In flat terrain the
weight penalty is minor but if there are hills enough to repeatedly drop your speed to below 10-12mph the fairing weight penalty is going to be noticeable. Fairings are most
easily mounted to LWB bikes. SWB bikes, esp with high BB make an adequate mount
that scoops air down below the level of the front axle difficult. A look at the Zipper
or Mueller websites for windscreens gives an idea of how difficult an adequate
windscreen is to place on a hi BB SWB. Fairings usually start with an adequate windscreen and then build on this to enclose the rider. Baccheta/ V Rex/ Volae type
frames are difficult to enclose. Tour Easy, Rotator Pursuits and very low bents or small wheel LWB bents are much easier to enclose. Steve
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Old 01-31-05, 01:48 PM   #6
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If fairings have full enough coverage they help you to ride warmer in the winter. Using a Mueller Windwrap mounting system, I mounted a homemade coroplastic fairing that is an aerodynamic disaster on my Greenspeed GTO. Last winter, when the weather was quite a bit worse than this one in Utah, the fairing kept me on the road in comfort.

Regards,

Gary, Greenspeed GTO, Salt Lake City
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Old 01-31-05, 02:57 PM   #7
izgod
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I have a Mueler fairing on my BikeE. It doesn't do much for speed, but it really helps keep freezing cold rain off my legs, and keeps my toes and hands warm, too. I use it mainly in winter.
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Old 01-31-05, 03:34 PM   #8
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All's fairing for innovative winter biker
http://www.chicagotribune.com/classi...,7030787.story

You might have to register, but this guy's got a three-wheeler recumbent with a full shell around it. Interesting.
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Old 01-31-05, 07:56 PM   #9
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Tail fairings also improve the efficiency more than what front fairings will. If you want to go faster, then do a tail fairing.
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Old 01-31-05, 09:02 PM   #10
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Quote:
Originally Posted by lowracer1
Tail fairings also improve the efficiency more than what front fairings will. If you want to go faster, then do a tail fairing.
LR1, it's true that tailboxes work better if the seating is very reclined, (i.e. lowracers) but my experience has been that the more upright seating positions seem to benefit more from a front fairing. My tailboxes gave at most 5% gain, and I had to be doing 22+ in order to even get that. A Speedster is pretty upright. A proper front fairing will prevent oncoming air from hitting the rider square in the chest and producing the dreaded parachute effect(tm).

OTOH, a front fairing would be pretty useless on your lowracers, because you're so reclined and the airflow up the front of the bike is pretty good anyway. There's nothing left for you to do but close off the wind shadow at the back of the bike, which is where the tailfairing comes in.

As far as overall pleasure, and discounting the speed aspect, it was still a joy to ride faired. I never once got sunburned legs when riding with a fairing. I could ride in light to moderate rain and most of me would stay dry unless I stopped. In a deluge I could stop and take it off to use as an umbrella. On cold mornings, I stayed warmer than everyone else. The only disadvantages it had were weight and transportation.

Last edited by BlazingPedals; 02-02-05 at 07:48 PM.
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Old 02-02-05, 01:32 PM   #11
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Thanks very much for the informative replies. I think I will try to build my own fairing, but since I live in Vancouver, BC, hills rather than weather are a problem.

First I'm going to look at other ways of speeding my bike up (get fitter, try thinner tires, and perhaps even better wheels -- the stock wheels on the EZ Speedster are not great).
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Old 02-03-05, 07:27 AM   #12
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Quote:
Originally Posted by sch
Fairings are not going to do much for you if you can't habitually ride above 20mph.
The improvement in aerodynamics adds only a little bit in the 16-20mph range, but
as you approach or exceed 25mph the power needed drops more noticeably.
What is all of this talk about riding at 15+ or 20+ mph. It is not the speed that you travel that makes a difference, it is the air velocity. If you are going 20 mph in a 20 mph tail wind the fairing is not going to do a thing. If you are traveling 10 mph in a 10 mph headwind, you have the 20 mph air velocity and the fairing should help.

Stay tuned for an upcomming post in a couple of months after I finish my wind tunnel tests in my home made wind tunnel.
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Old 02-03-05, 02:07 PM   #13
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I can assure you that I would not be traveling only 20mph with a 20mph tailwind. 4omph but not 20mph. 10mph into a 10mph headwind? comeone .......how bout some more realistic numbers. What is your wind tunnel going to accomplish. If you arent' a 20+mph rider on the flats, I don't see what a wind tunnel will do for you unless you plan on optimizing fairing construction for over 20+ riders.
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Old 02-03-05, 08:05 PM   #14
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It is true that it is your relative wind speed that is the operant here. In my area we almost never,
or rarely more than a few miles, have a true tailwind. Even if we do, bike speed relative to the
ground is almost always higher than windspeed in the direction of travel. Trees, terrain and vortexes
result in highly variable wind directions. I rode in Dallas 6mo ago and was told the wind is rarely less
than 8-10mph and the direction from the south or SW so you pretty much know what to expect day
in and day out. Hawaiians always have a constant wind from the west that rarely changes direction.
Central Ok and Ks will have constant winds in the 5-20mph range for days on end. In the eastern
half of the country a windtunnel derived info will be of interest but irrelevant as the wind direction
is so variable, road direction so variable that you 'always have a headwind'. Steve
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Old 02-03-05, 10:03 PM   #15
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Quote:
Originally Posted by lowracer1
I can assure you that I would not be traveling only 20mph with a 20mph tailwind. 4omph but not 20mph. 10mph into a 10mph headwind? comeone .......how bout some more realistic numbers. What is your wind tunnel going to accomplish. If you arent' a 20+mph rider on the flats, I don't see what a wind tunnel will do for you unless you plan on optimizing fairing construction for over 20+ riders.
Everybody's needs are different. For me, the fairing will be little more than a wind break during the morning commute to work. I usually have no wind to 5 mph tail wind then so at most it will keep me warmer in the spring and fall. On the rides home, it is common to have a 10 to 15 mph head wind. My average road speed is about 15 mph so I am facing a 25 to 30 mph air speed at the end of the day when I am tired. The fairing should be nice then. If it keeps me drier on those rainy days, I might even commute more often.

So far I have learned a lot from the wind tunnel but it has not helped with the fairing design. I learned that I need a bigger wind tunnel and larger models.
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