# Aerodynamic design for ebikes?



## ninjichor (Jul 12, 2018)

I'm thinking MotoGP style fenders for a start:

















These tire hugging designs act as a fairing and look less "Moto" than the MX style fenders that seemingly are more worried about tire and crud clearance.

Article that touches on fenders: https://janheine.wordpress.com/2018/01/16/myth-3-fenders-slow-you-down/

Basis of the idea: the UCI has a rule against fairings, among many others since they believe the sport should be about athleticism, rather than the equipment. Since ebikes sort of defies that idea, considering the nature of pedal-assist and how it allows mere mortals to have world cup leg power, how about some fairings for the sake of efficiency? It'll be functional weight that won't be an extra burden; not likely to be drafting off others and there's the bonus of limiting tire spray.


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## Velocipedist (Sep 3, 2005)

Skinsuits ftw?


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## J.B. Weld (Aug 13, 2012)

ninjichor said:


> Basis of the idea: the UCI has a rule against fairings, among many others since they believe the sport should be about athleticism, rather than the equipment.


UCI also has a rule against motors, because it's bicycle *racing*. I've never heard an argument against fenders for practical reasons, including training for racing in wet conditions.

I'm sure fenders will become common on electric commuter bikes because they're practical, and why not make them aero? That's practical too (saves watts).


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## honkinunit (Aug 6, 2004)

I'm not sure Zzipper fairings are actually more aero than not having one, but maybe ebikes can revive them. They have been around for 40 years. I used to see them occasionally on recumbents, but I have not seen one in years. Looks like they are still in business though.

https://www.zzipper.com/


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## Bigwheel (Jan 12, 2004)

After putting my first serious eRoadbike together a few years ago I put some thought into using a fairing of some sort to help cheat the air resistance. This is what I was considering:









However the reality is that bicycles with riders aboard are pretty light vehicles and while a fairing may aid when going directly with or a following wind any type of cross wind will have you holding on for dear life.

Moto's get by with this because they are heavier and therefore more planted on the road but even still cross winds on a faired bike can be very tricky.

That UPS eTrike they are going to trial in Portland may have enough ballast to not whip around too badly in a cross wind but I would imagine it will still be a handful when one is encountered.


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## J.B. Weld (Aug 13, 2012)

Bigwheel said:


> After putting my first serious eRoadbike together a few years ago I put some thought into using a fairing of some sort to help cheat the air resistance. This is what I was considering:
> 
> View attachment 1240474


lol, that would be terrifying!


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## honkinunit (Aug 6, 2004)

Bigwheel said:


> After putting my first serious eRoadbike together a few years ago I put some thought into using a fairing of some sort to help cheat the air resistance. This is what I was considering:
> 
> View attachment 1240474
> 
> ...


It looks like you spent a lot of time on that. Was it frame mounted or mounted to the handlebars? It looks like a fairing off of a 70's sportbike.

I wonder if you put a grill in the sides instead of having it be solid, if the airflow would improve from the frontal direction but not have as much surface from the side so that crosswinds could be mitigated slightly.

I have been in crosswinds so strong on my road bike that just staying on the road was impossible. It is really dumb to be riding any bike in those conditions, even a motorcycle. I learned that the hard way.

You would definitely have to choose fairing/no fairing based on the day, and I'm guessing even a 20 MPH cross wind would be a huge challenge with any kind of fairing on a bicycle. We get winds 20 MPH and higher really frequently along the Front Range, and they are unpredictable.


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## MikeTowpathTraveler (Aug 12, 2015)

Fenders would be a nice thing to have on my Haibike Full FatSix not as some aero aid, but simply to keep the crap off the bike that gets thrown by the tires, especially during the Mud Season.

I've noted on both of my fat bikes that heavy cross winds will grab the front tire if your mind is off wandering elsewhere.....

Back in the late 90's I bought a BikeE recumbent; their off-road, dual suspension model. Purchased their pannier rack, front and rear fenders made for this bike along with the Mueller Human Power fairing for it. On the road, top end speed was increased with the fairing versus without it (top end speed was not a hallmark of these particular recumbents). But I have to tell you, the moment the warm weather came back, you were getting no air flow on your body with that fairing blocking the wind.

The NJ Turnpike as well as the Delaware Memorial Bridge crossing of the Delaware River in South NJ and Delaware often has motorcycle and trailer bans when the wind is blowing good....


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## Bigwheel (Jan 12, 2004)

"It looks like you spent a lot of time on that. "

Only long enough to google "bicycle fairings" and peruse google photo's.

I went out in 30kt winds one day just for shites and giggles on my 1000w front hub motor (legal in OR so put your weapons down) to see just how much headwind I could conquer going a decent speed and it actually was surprising as long as I kept the watts up there just how fast I could go into it. It was a loop so there were out, back and side winds and you could feel the wind effect on the hub motor in the side wind for sure but could kind of tack with it.

Seriously any of the "solutions" for use during rain or any kind of foul weather, which generally are associated with higher wind speeds, are a joke.









But this failed Kickstarter campaign did catch my eye as at least semi useful looking as my hands do get cold easily:









As far as wind goes the assist does a good job of countering it I find but it just eats up wh's if you try and really get through it quickly but more than likely in that situation you are not going for distance, just somewhere quickly to hunker down!


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## J.B. Weld (Aug 13, 2012)

craigsj said:


> It is unclear why aero aids would be desirable on an e-bike considering they would contribute to precisely the problem that regulation tries to address. The goal isn't to increase speeds, it's to control them and electrical costs are already miniscule.


Could potentially help to increase range.


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## chazpat (Sep 23, 2006)

Just go with aero bars. If I remember correctly, you have to be going over 17mph before aerodynamics really have any affect.


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## ninjichor (Jul 12, 2018)

chazpat said:


> Just go with aero bars. If I remember correctly, you have to be going over 17mph before aerodynamics really have any affect.



















Like this? https://forums.mtbr.com/xc-racing-t...-bar-ends-29-xc-bike-861819.html#post10488942


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## Bigwheel (Jan 12, 2004)

I prefer drop bars for my road bikes. In order to set them up with eBike controls you just have to get creative









Thumb throttle placed exactly where it works the best, red regen button ditto and mandatory bell ready to ring. Display nicely out of the way and plenty of room for different hand positions.


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## Gutch (Dec 17, 2010)

I believe there’s some sarcasm here! Wtf, fairings? Dang, just go buy a Ninja (no pun intended!)


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## chazpat (Sep 23, 2006)

craigsj said:


> How many road motorcycles do you see with aero bars to squeeze out a bit more fuel economy?


So I guess ebikes are more like motorcycles then is what you are saying.


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## portnuefpeddler (Jun 14, 2016)

Years ago I had a 440 Kawasaki road bike, with a slick handle bar type fairing. I discovered that if I had a sleeping bag tied onto the sissy bar, I could lean back against it and then put my feet up into the fairing, while still being able to steer etc. Lifting my feet up was good for less then 5 mph, 3 or so I think it was, while doing 70.


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## J.B. Weld (Aug 13, 2012)

craigsj said:


> Classic MTBR garbage.


Well that is kind of what you said.

Why do sport motorcycles place their riders in an aerodynamic position?


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## J.B. Weld (Aug 13, 2012)

craigsj said:


> It is not remotely what I said, nor does anyone believe it was.
> 
> I think you can figure out why "sport motorcycles" do it and why it's different from e-bikes, but by all means drive the thread into the trashcan.


Sorry, forget to attach a goofy emoji to my last post.


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## JackWare (Aug 8, 2016)

But will the fairing accommodate the rider in a comfortable attack position?


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## Gutch (Dec 17, 2010)

Ok, just stop. This is one of the most ridiculous threads I’ve read. Fairings? Really? Nothing against the OP, at what point do you say, wrong topic?


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## vikb (Sep 7, 2008)

Just makes sense . Fairings should be standard on all e-bikes.


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