The biggest problem at 25mph+ is rarely discussed resistance

General Discussion about electric bicycles.
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by Alan B » May 07, 2016 11:34 am

You'll want a discreet battery, not a discrete one, or perhaps both, but being discreet is the goal:

https://www.vocabulary.com/articles/cho ... -discrete/

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by cycleops612 » May 07, 2016 12:30 pm

Quite right. Just tired. Thanks.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by cycleops612 » May 30, 2016 6:49 am

cycleops612 wrote:Or so it seems?

So many want more range and speed, but seek answers ~only in more power and weight.

Fairings, lycra, aerodynamic panniers, bigger wheels ... seem treated as minor issues with ebikes, when in fact it is the biggest issue at approaching car type speeds, and increases exponentially beyond a certain point. Then there are days you face a headwind.

Anyhoo, preamble aside, a heretical? suggestion which one would think may suit many who want fast and range, is a simple traditional (post mig welding manufacture seems wise?) road bike with drop bars, 28" racing wheels & tyres ? and a simple front hub motor.

I often had a total load of 100kg (i am 75kg) on my 12.5kg chromoly? racing bike. Never was grip an issue with so little weight.

If you have a long commute, there is the option of; cheap, light, slippery, more effective pedal input, and smaller/lighter/cheaper battery.

Drop bars can seem intimidating, but you get used to the two hand positions. A thumb throttle sounds best to be reachable from either.
AN ERROR correction and further info

see wind resistance charts here

https://tunedintocycling.com/2014/06/28 ... esistance/

after 25kph (NOT 25MPH as wrongly stated during the thread) (sustained using 100watts), you need another 100 watts per extra 5kph. Suitable battery weight gets out of hand fast if u wanna push this wind envelope sitting upright. If you must, then 25kph still sounds a good speed to do it at. 5kph more, halves your range.

I am sure we all have a feel for when that point is reached, am just providing wind tests to prove it.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by ebent » May 30, 2016 10:32 am

Ive been riding a recumbent trike for more than 10 years. I burn less than 16 watts per mile and I am willing to use throttle. If you were to give a recumbent a reasonable trial, say a week of riding, you would not think that recumbents are creepy. If you do try one make sure you have a large colorful flag. Recumbents are designed for aero. And will answer your challenge if you can get past your mental block...
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by Chalo » May 30, 2016 11:50 am

Not all recumbent bikes are more aerodynamic than normal bikes of reasonably sporting layout. Those that are, like, half as practical and manageable as a real bike tend to have just as much drag. None of the recumbents that my shop can offer (Sun brand from J&B Importers) are as fast as a normal bike, for instance.

To get big aero benefits, you have to get very horizontal, or else have a fairing. Both these things come with major compromises in functionality and handling.

Also, recumbents sharply limit the rider's ability to make pedal power. When electric power is also sharply limited by local laws, you want to be able to use your muscles to best effect... which means using a normal bike.
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by LewTwo » May 30, 2016 12:37 pm

Chalo wrote:Not all recumbent bikes are more aerodynamic than normal bikes of reasonably sporting layout. Those that are, like, half as practical and manageable as a real bike tend to have just as much drag. None of the recumbents that my shop can offer (Sun brand from J&B Importers) are as fast as a normal bike, for instance.

To get big aero benefits, you have to get very horizontal, or else have a fairing. Both these things come with major compromises in functionality and handling.

Also, recumbents sharply limit the rider's ability to make pedal power. When electric power is also sharply limited by local laws, you want to be able to use your muscles to best effect... which means using a normal bike.
More to the point in a crowded urban environment you can not see over, around or into the larger vehicles and the drivers of those two ton plus vehicles can not see you (not that they are bothering to be looking).
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by ebent » May 30, 2016 1:11 pm

Visibility is an issue however it is not as bad as you may think. I ride with a large colorful flag on a 6' pole. There have been occasions that i forgot my flag. The response from cars let me know that quickly. My current trike came with a 4' pole. It felt wrong in terms of car seeing me. I changed it to 6 and all was fine. I know Sun bents are in the starter category, not mid of high end. But good value. But no meaningful aero. But more than half of recumbents have it. Certainly in any shop that specializes in bents. Shorter distances 2 wheel is better. But I don't race anyway. But the number one reason I ride recumbent is an hour later my voice has not risen by an octave or 2. By far it is more comfortable. And with a motor I can go faster than I want. My net benefit is aero and comfort. Good aero equals better battery consumption.
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by Alan B » May 30, 2016 4:00 pm

My experiments with a recumbent BikeE with a rear BMC gearmotor are that it is more efficient than a road bike when the riders are upright, and it is much more efficient than a mountain bike no matter the rider's position. It uses so much less power than my mountain ebike that I ended up reducing the battery pack for the usual rides, I just didn't need the capacity.

These experiments were performed rolling down slight gradients at moderate speeds with no motor or pedal input using Schwalbe Big Apple tires. Having your legs horizontal and your body leaned back instead of perpendicular to the airflow really makes a difference, and this difference increases with speed.

If you are not familiar with the BikeE, it is not an extreme recumbent, it is more like sitting on a lawn chair. It is not great for pedaling hard but the efficiency improvement is amazing compared to mountain bikes and comparable to a very uncomfortable position on a racing bike. It is very visible and you can see better than you can when tucked in looking at the ground craning your neck to see out in an efficient racing position.

The visibility of the BikeE is not a problem, you are eye to eye with cars, and the comfort level compared to leaning on your hands and bending your back on a road bike allows longer riding times with fewer problems after the ride.

What racing bikes are made for and what we want to do with our ebikes is not really the same. Being able to put huge amounts of leg power into the bike is not useful for long range riding where we non-super athletes need to conserve energy. A racing frame is suited for bursts of power by an athlete who can maintain those uncomfortable body positions for long periods of time. What we need is something that is efficient and comfortable for long rides, and facilitates our ability to keep riding without back, shoulder, arm, neck or hand problems. Just like most of us don't drive racing cars on the street, as they are optimized for different use-cases than our daily driver needs.

For short, fast trips we do have the option of just carrying enough battery to overcome the losses, even with fairly inefficient tires and body position. As the distances are increased this becomes impractical at some point. That's when the efficiency becomes much more important, or our design begins to traverse into a different class of vehicle due to the increasing weight.

For a short to moderate length road ride my Borg is great, with huge battery and inefficient tires, but for a long ride the BikeE is better. For rides in the dirt with low speed and severe gradients the BBSHD equipped RidgeRunner works out better. Like other tools, they are optimized for different situations.

So it all depends on what you want, how far (and fast) you want to go, how light you want your ebike to be, and how much contortion and spandex you can tolerate.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by cycleops612 » May 30, 2016 7:44 pm

ebent wrote:Ive been riding a recumbent trike for more than 10 years. I burn less than 16 watts per mile and I am willing to use throttle. If you were to give a recumbent a reasonable trial, say a week of riding, you would not think that recumbents are creepy. If you do try one make sure you have a large colorful flag. Recumbents are designed for aero. And will answer your challenge if you can get past your mental block...
Thanks, u r right. Dont knock what u ain tried. I hate it in others.

I also have a thing about the width of trikes.

It detracts from my main safety strategy - assume the bastards cant see or dont care, and maintain max freedom to maneuver away.

trikes in traffic or rural riding basically need a lane like a car. Not a good look with such speed differentials methinks. In oz, the roads are small and the trucks are big. someone i knew was killed on a rural road, "sucked/wind destabilised" under the wheels i suspect.

I am more attracted to the presumably more difficult 2 wheelers.

maybe a good biz plan - rent a recumbent for a day/week?

16 watts??? u gotta love bikes aye? even a piddly 350wh is 22 miles or ~40km.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by cycleops612 » May 30, 2016 7:58 pm

Alan B wrote:My experiments with a recumbent BikeE with a rear BMC gearmotor are that it is more efficient than a road bike when the riders are upright, and it is much more efficient than a mountain bike no matter the rider's position. It uses so much less power than my mountain ebike that I ended up reducing the battery pack for the usual rides, I just didn't need the capacity.

These experiments were performed rolling down slight gradients at moderate speeds with no motor or pedal input using Schwalbe Big Apple tires. Having your legs horizontal and your body leaned back instead of perpendicular to the airflow really makes a difference, and this difference increases with speed.

If you are not familiar with the BikeE, it is not an extreme recumbent, it is more like sitting on a lawn chair. It is not great for pedaling hard but the efficiency improvement is amazing compared to mountain bikes and comparable to a very uncomfortable position on a racing bike. It is very visible and you can see better than you can when tucked in looking at the ground craning your neck to see out in an efficient racing position.

The visibility of the BikeE is not a problem, you are eye to eye with cars, and the comfort level compared to leaning on your hands and bending your back on a road bike allows longer riding times with fewer problems after the ride.

What racing bikes are made for and what we want to do with our ebikes is not really the same. Being able to put huge amounts of leg power into the bike is not useful for long range riding where we non-super athletes need to conserve energy. A racing frame is suited for bursts of power by an athlete who can maintain those uncomfortable body positions for long periods of time. What we need is something that is efficient and comfortable for long rides, and facilitates our ability to keep riding without back, shoulder, arm, neck or hand problems. Just like most of us don't drive racing cars on the street, as they are optimized for different use-cases than our daily driver needs.

For short, fast trips we do have the option of just carrying enough battery to overcome the losses, even with fairly inefficient tires and body position. As the distances are increased this becomes impractical at some point. That's when the efficiency becomes much more important, or our design begins to traverse into a different class of vehicle due to the increasing weight.

For a short to moderate length road ride my Borg is great, with huge battery and inefficient tires, but for a long ride the BikeE is better. For rides in the dirt with low speed and severe gradients the BBSHD equipped RidgeRunner works out better. Like other tools, they are optimized for different situations.

So it all depends on what you want, how far (and fast) you want to go, how light you want your ebike to be, and how much contortion and spandex you can tolerate.
Just a related thought, but perhaps a muscle magnifier machine like a bike ought experiment with a device which harnesses movement mimicing freestyle swimming (horizontal is also good from a resistance viewpoint) or similar. It seems there are many more muscles other than legs which could be harnessed.

Yeah - am sure some torso muscles help a bit, but not much.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by cycleops612 » May 30, 2016 8:25 pm

Just saying, but on reflection re my drop bar days, much of my ~relaxed/economical riding was no different from a normal bike, just using the top flatbar. So no less comfort. Brakes are ready and handy in either mode, trust me.

They are a boon in nasty headwinds of course. Its not uncommon getting 25kph winds round here. Thats 100 watts penalty right there on a roadbike.

Pausing in my argument to stress gravity - it is a battery, provided.... Each watt u expend climbing, ~.95~ of it can be retrieved if u play your cards right and dont waste it on the brakes or wind resistance. Use it in bursts or lose it, and that means fast runs downhill, whence the drop bars are great for maximising the work done from the free power.

SO IMHO, for me the norm wasnt hunched, and drop bars are 2 mode. Comfort/ok comfort, low/hi speed posture, and perhaps a helpful, obscure way of looking at drop bars.

I have almost talked myself into considering them on a MTB ebike.

The lean on bars may well be good too - dunno.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by Chalo » May 30, 2016 8:42 pm

Alan B wrote:If you are not familiar with the BikeE, it is not an extreme recumbent, it is more like sitting on a lawn chair. It is not great for pedaling hard but the efficiency improvement is amazing compared to mountain bikes and comparable to a very uncomfortable position on a racing bike.
That's simply not true. I have plenty of riding experience on the BikeE, and I can affirm that it goes slower while demanding more physical effort than a regular city bike.

The tiny wheels also make it ride worse than a normal bike, and the handling is some of the most treacherous I've ever experienced on two wheels.

It's not the worst chair I've ever sat in, but it's probably the worst bike I've ever ridden. And I've ridden hundreds.
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by Alan B » May 31, 2016 2:03 am

Chalo wrote:
Alan B wrote:If you are not familiar with the BikeE, it is not an extreme recumbent, it is more like sitting on a lawn chair. It is not great for pedaling hard but the efficiency improvement is amazing compared to mountain bikes and comparable to a very uncomfortable position on a racing bike.
That's simply not true. I have plenty of riding experience on the BikeE, and I can affirm that it goes slower while demanding more physical effort than a regular city bike.

The tiny wheels also make it ride worse than a normal bike, and the handling is some of the most treacherous I've ever experienced on two wheels.

It's not the worst chair I've ever sat in, but it's probably the worst bike I've ever ridden. And I've ridden hundreds.
I think we're talking about different things.

It is not the best recumbent I'm sure, and I haven't ridden it enough to become as comfortable with it as I am with diamond frames, but the efficiency measurements are simple and easy to make. I also know folks who ride the BikeE one handed while looking back over their shoulder talking, clearly there is some point where one becomes accustomed to the handling.

You might be right for your perception of body mechanical efficiency while pedaling it, but that doesn't directly apply to gliding and electric motoring. I've done it and measured it and compared it in the real world to many bikes and to a tadpole trike. It is easy to see when one bike out-rolls a bunch of others on the road, or when you add up the watt-hours per mile at the end of a ride.

I don't think riding a bike for a few minutes or hours gives enough experience, especially with a system that is as different from the normal bike as a recumbent is. It takes a serious commitment to retrain for a big change. From what I've read the racers who convert to recumbent take quite a while to retrain the different muscles used to regain their speed and climbing. So it is not an afternoon process. Clearly there are better recumbents too, but the electrical and rolling efficiency that I measure even with this "poor" one is very impressive, and electrifying a lightweight road bike is much more difficult than a sturdy recumbent.

The scientific data also backs this up, the EasyRacer (another very moderate recumbent) has about 10% less effective frontal area than a full racing dropped down position on a road bike. A person sitting up or leaning forward with legs sticking forward and down is just not as good an aero setup than even a mild recumbent.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by DrkAngel » Jun 02, 2016 7:18 am

Made up a quick resistance chart for various bike types at various speeds.

(Wind Resistance & Road Load)
Image

See - Efficiency
And - Aerodynamic Factors
And - Speed vs Range
And - Rolling Resistance (RR) - Understanding Tires
.
.
.
.
Attachments
Watts = Speed.jpg
Watts = Speed.jpg (95.91 KiB) Viewed 577 times
Last edited by DrkAngel on Jun 02, 2016 10:55 am, edited 3 times in total.
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by cycleops612 » Jun 02, 2016 8:42 am

DrkAngel wrote:Bade up a quick resistance chart for various bike types at various speeds.

Image

See - Efficiency
And - Aerodynamic Factors
Nice bading my good fellow.

I reiterate my correction re 25MPH. it should have been 25kph which is 15mph (in the roadbike tests i saw)

Anyhoo, its the relative, not the absolute numbers which matter.

What we see here is that investing 170-200 watts in steady locomotion is a nice balance of range and speed on a mtb/roadbike. Then the curve starts getting steep, and range/battery weight suffers inordinately .

The curve remains relatively quite flat for the impressive incumbent recumbent, so the cost benefit still looks ok at an applied 400w.
Ssticking with the more relevant to most MTB here, we get~; 12.5mph from 100w, 16mph from 200w (+3.5mph), 19mph from 300w (+3mph) & 21.5mph at 400w (+2.5mph).

The second 100w gains 3.5 times less speed than the first 100w.

The other chart i saw, btw, has a line for other friction. Its small and increases little with speed. These numbers are ~due to wind alone.

so yeah, 15(25kph)-16mph & about 170-200w seems optimal on a MTB.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by DrkAngel » Jun 02, 2016 12:35 pm

Above graph is Wind Resistance & Road Load

For a itemized breakdown I suggest this graph fron Sheldon Brown

Image
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by Bike_on » Jun 02, 2016 12:54 pm

cycleops612 wrote:Or so it seems?

So many want more range and speed, but seek answers ~only in more power and weight.

Fairings, lycra, aerodynamic panniers, bigger wheels ... seem treated as minor issues with ebikes, when in fact it is the biggest issue at approaching car type speeds, and increases exponentially beyond a certain point. Then there are days you face a headwind.

Anyhoo, preamble aside, a heretical? suggestion which one would think may suit many who want fast and range, is a simple traditional (post mig welding manufacture seems wise?) road bike with drop bars, 28" racing wheels & tyres ? and a simple front hub motor.

I often had a total load of 100kg (i am 75kg) on my 12.5kg chromoly? racing bike. Never was grip an issue with so little weight.

If you have a long commute, there is the option of; cheap, light, slippery, more effective pedal input, and smaller/lighter/cheaper battery.

Drop bars can seem intimidating, but you get used to the two hand positions. A thumb throttle sounds best to be reachable from either.
I bought a nice road bike @ bikesdirect and put a Falco high speed hub on it and road for a couple years. 28mm tires.

It was fast. Shifting with Ultegra components and a 50/34 front rings were fine and could maintain 25+. The issue is high speed wear on the frame/spokes/drops. I even used torque bar. The front carbon fork lasted, but the comfort at higher speeds on bumpy roads was poor.

It is a way to get there. 40lb bike. 500W hub, 36V/11.6ah battery. 22-24mph averages.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by cycleops612 » Jun 02, 2016 3:20 pm

Bike_on wrote:
cycleops612 wrote:Or so it seems?

So many want more range and speed, but seek answers ~only in more power and weight.

Fairings, lycra, aerodynamic panniers, bigger wheels ... seem treated as minor issues with ebikes, when in fact it is the biggest issue at approaching car type speeds, and increases exponentially beyond a certain point. Then there are days you face a headwind.

Anyhoo, preamble aside, a heretical? suggestion which one would think may suit many who want fast and range, is a simple traditional (post mig welding manufacture seems wise?) road bike with drop bars, 28" racing wheels & tyres ? and a simple front hub motor.

I often had a total load of 100kg (i am 75kg) on my 12.5kg chromoly? racing bike. Never was grip an issue with so little weight.

If you have a long commute, there is the option of; cheap, light, slippery, more effective pedal input, and smaller/lighter/cheaper battery.

Drop bars can seem intimidating, but you get used to the two hand positions. A thumb throttle sounds best to be reachable from either.
I bought a nice road bike @ bikesdirect and put a Falco high speed hub on it and road for a couple years. 28mm tires.

It was fast. Shifting with Ultegra components and a 50/34 front rings were fine and could maintain 25+. The issue is high speed wear on the frame/spokes/drops. I even used torque bar. The front carbon fork lasted, but the comfort at higher speeds on bumpy roads was poor.

It is a way to get there. 40lb bike. 500W hub, 36V/11.6ah battery. 22-24mph averages.
ta for sharing, no substitute for having done it

yeah well, 500w, theres your proble aybe

dunno

specifically, it was a triathlon bike if that matters

how about, a 12kg bike, 3kg Xiongda dual speed hub - 350w,

battery is tricky. If its a commute app, its good to fine tune it. personally, i ~never use more than 25%, which is really ~1/3rd of my battery, so 2/3 is dead weight.

spending longer than an hour on a bike seems a bit much to me. so assuming an hr max & a charger at work

180w for 25 mins (60wh) for steady 25-30kph, allow 350 watts use for 15 mins of the hour (=60wh~)& 20mins for coasting and stuff

=120wh total for an hour commute trip of under 25km, conservative, and not even pedaling.

a 220wh lipo i looked up as a sample was 1.5kg - just saying - its 220 wh is all. we may get by with 1kg.

a rider not much more than 80kg

then 16kg total is not bad with the dual speed.

I do see the problem, its a more delicate frame, but i am not convinced that if the motor etc. are minimalist, a ~100kg gvm bike and rider, could still achieve fun and practical power to weight ratios. For lighter riders, even exciting.

The reality is that the main of reasonable sustained speed is wind, and drop bars can achieve as much as considerably more weight, power and expense.

i repeat, its a pedal when u r ready strategy. Thats great, but optional. you dont have to be fit or rich.

maybe save a kilo with a lighter hub and more pedaling. If the native gearing is right, a single speed hub is v cheap, light, & could blend well with the now much easier pedaling.

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by nycmetrotadpole » Jun 05, 2016 1:40 am

easy racers goldrush or its cro-mo twin the tour easy are probably the best recumbents to use in urban areas, i have been using one for years riding into and all around NYC , over the bridges into Brooklyn,queens and jersey.
I have a fairing that is pretty easy to put on/off , in summer i prefer the fairing off most of the time since i like the breeze. with the fairing off the loss of speed is very pronounced at over 15 mph, that is when the fairing really Kicks in, above 15 mph the biggest obstacle is wind . These are observations under pure pedal power, with the fairing when i hit just above 15mph , i fell like i just got a free boost and i can keep the speed above 15MPH , it is like i am in overdrive.
The long wheel base recumbent tend to be the ones that get the best streamlining with fairings, the whole body has to be close enough to the fairing to get max aero. The feet need to be behind the fairing to keep them out of the wind.
Rans makes some lwb,
I have tried rans vrex, bike E, and the goldrush is IMO the best urban bike, and this is without adding e assist. The bike-E is a good urban bike, not fast, but comfortable and has the added benefit of fitting in public transit elevators. Problem with a bikeE it is not versatile , once out of the urban area, it sucks on the open road, slow as shit, except on the internet bike-E group where they all were doing 30 mph on Level ground with no assist. V rex is a nice SWB bent good on open road but i found it too squirrely when starting from a dead stop on hills, this happens a lot due to pedestrians an
since goldrush are usually seen with fairings. most of the NYC people use them year round, adding an e-m assist will not draw any added attention. For year s people have questioned me whether my goldrush had a motor and it didnt then, now it does .
Knowing the power i have saved when riding under my own power with a fairing, it is a no-brainer to imagine the e-assist power i would save with a fairing.
I wish i could make my trike suitable to prevent me to be roadkill in NYC, but until i can project a hologram above me, that isnt happening

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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by linear » Nov 29, 2017 2:44 pm

nycmetrotadpole wrote:
Jun 05, 2016 1:40 am
easy racers goldrush or its cro-mo twin the tour easy are probably the best recumbents to use in urban areas, i have been using one for years riding into and all around NYC , over the bridges into Brooklyn,queens and jersey.
I have a fairing that is pretty easy to put on/off , in summer i prefer the fairing off most of the time since i like the breeze. with the fairing off the loss of speed is very pronounced at over 15 mph, that is when the fairing really Kicks in, above 15 mph the biggest obstacle is wind . These are observations under pure pedal power, with the fairing when i hit just above 15mph , i fell like i just got a free boost and i can keep the speed above 15MPH , it is like i am in overdrive.
The long wheel base recumbent tend to be the ones that get the best streamlining with fairings, the whole body has to be close enough to the fairing to get max aero. The feet need to be behind the fairing to keep them out of the wind.
Very glad I read this thread, as it inspired me to pull out the "tour easy clone" have not used it for about 8 years. Did 3 short rides today up in Michigan, sunny day, seems to be a very efficient ride. Now planning to put a DD hub in the back, as I am now sort of into the regen/electric brake aspect of Ebiking. Will need a way to bleed off speed with this combo.,.
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Chalo
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Re: The biggest problem at 25mph+ is rarely discussed resistance

Post by Chalo » Nov 30, 2017 1:27 am

Tour Easy is a well proven design. With good efficient tires and a carefully matched motor drive, it should be capable of superior speed compared to a normal bike, even if you don't use one of the bubble fairings available for it. Take care to use effective and reliable brakes. It would probably be a good idea to have strong low-mounted front lighting for it, too, because you can't stand up if you see a bump to late to avoid it.

I'd consider a geared hub motor like MAC, because coasting out for long intervals is a useful strategy with such a bike, if you don't add sources of drag. A high capacity battery would be a good idea as well, because your endurance in the saddle on that bike allows you a long range before fatigue limits your ride.
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Re: The biggest problem at 25mph+ is rarely discussed resist

Post by Robocog » Dec 03, 2017 10:36 pm

Chalo wrote:
Apr 24, 2016 12:39 pm
The easy things you can do to reduce aerodynamic drag all decrease comfort substantially. The more elaborate things you can do all make the bike heavier, more fragile, more expensive in time and money, and a heck of a lot more difficult to live with day to day.

My favorite solution is not to go fast enough for drag to be a big problem. Because it's not just aero drag you get at higher speeds; it's also unpleasant noise, stress, and risk of serious injury.

Even the fastest cars and motorcycles average about 10mph point-to-point in the central city. Ride a 20mph e-bike and you can get door to door faster most of the time.
Sheer genius, every word. But, MY idea is, an inflatable jacket thingie. So that, in the crouch, on your mountainbike, you are streamlined. IT could have cooling channels like a helmet. It would make you essentially a streamliner, sorta.

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Re: The biggest problem at 25mph+ is rarely discussed resistance

Post by DRMousseau » Dec 03, 2017 11:56 pm

hehehe,.... I'm gigglin' a little.

I live year-around in a 34' motorhome,.... you know, those big boxes that only get 6mpg regardless of city or highway. It actually rolls easy, a 6hp garden tractor could pull it. But even with a garden tractor moving it at a crawl, still 6mpg,.. and better hope for no headwind! lol! Any added "resistance" is pure heck!!! Overcoming frontal resistance plagues everyone.

I noticed those charts and such above, only reach to about 45mph or so. THAT'S when "drag" kicks in,.. the force that "pulls" you back! IF, you could pedal or motor up to that 45 behind my RV (it's lower to the ground than most trucks),.... then that "drag" (vacuum) behind me, will be all you need at any speeds greater, and you likely be riding the brake to keep from becoming attached to my bumper, since you'll have no headwind resistance to overcome back there. Those who've ridden motorcycles wildly on the expressway, know jus what I mean. Or maybe you've been brave in a car and ventured into that little pocket behind me,... talk about mileage improvement! With little resistance and my drag pulling you! WoW! :shock:

But on a bike, I can only overcome so much,... much less than "trimmer" more "athletic" folks. E-bike is much better at that "athletic" lack. Still, I only tolerate so much on my face, whatever position,.... tailwinds are better. :wink:

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