Is wind resistance really that important on an Ebike?

[DanEL]

I don't have an electric powered bike yet but from what I've read here you really have to change your thinking as to what is most important when choosing an ideal ebike configuration vs. a regular human powered bicycle. For example, I understand that on an ebike frame strength is more important than frame weight so a heavy duty steel frame is often better than a lightweight carbon frame.

Another area in which I may have to change my thinking is the importance of rider position and aerodynamics. On a regular road bike it is important to keep bars low so you can maintain a flat back aerodynamic riding position to maintain high speed. I would imagine this would be less important on an ebike. I really like the upright riding position on an Electra Townie. My question is how much of a decrease in performance will I give up by choosing a bike with an upright riding position vs. a traditional drop bar road bicycle?

Here are a few particulars that might be helpful to know to help me make the best decision:

* I live near Pittsburgh where the terrain is somewhat hilly. I've heard it's similar to San Francisco in that respect. So I won't be traveling at top speed going up hill.
* It's not especially windy here.
* I am thinking about getting the Nine Continent kit from ebikes.ca: http://ebikes.ca/store/store_nc.php using a 26" wheel and running it at 48v. I haven't decided on batteries yet but hope to get some providing a range of 20 plus miles. (Don't want lead acid batteries)
* I would like the top speed of the bike to be 25 mph plus if possible.
* I will use a bike with a derailleur system, either 6-7 speeds or more if I get a multiple front chain ring.
* I will pedal as I ride to try to get some exercise but I don't want to get winded (I'll use my regular bike for that!)

So how much top speed will I give up with an upright riding position (Electra Townie) vs. a road bicycle with drop bars? How much will my range decrease? If the top speed decreases by 1-2 mph and the range drops by a mile or two I'll probably choose comfort over better performance.

 

[biohazardman]

I don't have an electric powered bike yet but from what I've read here you really have to change your thinking as to what is most important when choosing an ideal ebike configuration vs. a regular human powered bicycle. For example, I understand that on an ebike frame strength is more important than frame weight so a heavy duty steel frame is often better than a lightweight carbon frame.

Another area in which I may have to change my thinking is the importance of rider position and aerodynamics. On a regular road bike it is important to keep bars low so you can maintain a flat back aerodynamic riding position to maintain high speed. I would imagine this would be less important on an ebike. I really like the upright riding position on an Electra Townie. My question is how much of a decrease in performance will I give up by choosing a bike with an upright riding position vs. a traditional drop bar road bicycle?

Here are a few particulars that might be helpful to know to help me make the best decision:

* I live near Pittsburgh where the terrain is somewhat hilly. I've heard it's similar to San Francisco in that respect. So I won't be traveling at top speed going up hill.
* It's not especially windy here.
* I am thinking about getting the Nine Continent kit from ebikes.ca: http://ebikes.ca/store/store_nc.php using a 26" wheel and running it at 48v. I haven't decided on batteries yet but hope to get some providing a range of 20 plus miles. (Don't want lead acid batteries)
* I would like the top speed of the bike to be 25 mph plus if possible.
* I will use a bike with a derailleur system, either 6-7 speeds or more if I get a multiple front chain ring.
* I will pedal as I ride to try to get some exercise but I don't want to get winded (I'll use my regular bike for that!)

So how much top speed will I give up with an upright riding position (Electra Townie) vs. a road bicycle with drop bars? How much will my range decrease? If the top speed decreases by 1-2 mph and the range drops by a mile or two I'll probably choose comfort over better performance.

Top speed decreases by 1-2 mph and the range drops by a mile or two. You said it and it's the way it is. I am running a GM 500w on 48V and tucking in will take my speed up to 24-25 from 22-23. I really haven’t checked on the range, it's more comfortable to ride sitting up but expect you are correct there also. A bit of a head wind will decrease your range significantly.

 

[pwbset]

Hey Dan... I grew up in Indianola/Cheswick (yay #6 for the Stillers!). I now live in Montana where the hills are actually mountains. I can all but promise you that if you don't get a 5 series clyte motor or a high wound over volted 4 series or a geared setup with at least one metal gear then you will be really disappointed with performance. A NineCont @ 48v isn't going to cut it I'm afraid. I know the 'burgh so let me know specifically where you are and that'll give me an idea of the hills you'll be riding.

 

[pwbset]

Oh yeah... by all means get a hold of ES member Lenk42602 somehow... he's in the 'burgh and rode the ARB from the Zoo to Oakmont a lot (talk about a crazy ride!)... he can help you get what you need and not be under powered etc. etc. I haven't seen any posts from him lately, but maybe he's still around. Here's his website:

http://www.electricpedaler.com

 

[Russell]

Most of the same factors which influence the performance of human only powered bicycles also affect ebikes. If you think about it you are simply supplanting or augmenting the human motor with an electrical motor. Cyclists of varying size and physical condition could be though of as having different "watt" ratings just like motors and if you look strictly at muscle glycogen levels can be depleted in 2 hours or less if going "full throttle" leaving the cyclist to bump along on fat stores kinda like a spent battery hitting the LVC.

-R

 

[Toshi]

I don't have an electric powered bike yet but from what I've read here you really have to change your thinking as to what is most important when choosing an ideal ebike configuration vs. a regular human powered bicycle. For example, I understand that on an ebike frame strength is more important than frame weight so a heavy duty steel frame is often better than a lightweight carbon frame.

Another area in which I may have to change my thinking is the importance of rider position and aerodynamics. On a regular road bike it is important to keep bars low so you can maintain a flat back aerodynamic riding position to maintain high speed. I would imagine this would be less important on an ebike. I really like the upright riding position on an Electra Townie. My question is how much of a decrease in performance will I give up by choosing a bike with an upright riding position vs. a traditional drop bar road bicycle?

Here are a few particulars that might be helpful to know to help me make the best decision:

* I live near Pittsburgh where the terrain is somewhat hilly. I've heard it's similar to San Francisco in that respect. So I won't be traveling at top speed going up hill.
* It's not especially windy here.
* I am thinking about getting the Nine Continent kit from ebikes.ca: http://ebikes.ca/store/store_nc.php using a 26" wheel and running it at 48v. I haven't decided on batteries yet but hope to get some providing a range of 20 plus miles. (Don't want lead acid batteries)
* I would like the top speed of the bike to be 25 mph plus if possible.
* I will use a bike with a derailleur system, either 6-7 speeds or more if I get a multiple front chain ring.
* I will pedal as I ride to try to get some exercise but I don't want to get winded (I'll use my regular bike for that!)

So how much top speed will I give up with an upright riding position (Electra Townie) vs. a road bicycle with drop bars? How much will my range decrease? If the top speed decreases by 1-2 mph and the range drops by a mile or two I'll probably choose comfort over better performance.

i invite you to read these three threads of mine (they're chronological):

http://endless-sphere.com/forums/viewtopic.php?f=3&t=3845
http://endless-sphere.com/forums/viewtopic.php?f=3&t=3878
http://endless-sphere.com/forums/viewtopic.php?f=3&t=3999

 

[nomad85]

If you get the speed version in a 26" wheel you will get the speed you want from a nine-continents kit. I love mine. I get to 28mph @48v even in the wind(unless its really windy, but it almost never goes below 24) with no wind or a slight tailwind I can go 30-31mph @48v.

 

[dogman dan]

Running the Aotema , WE type, motor, at 36v, I ride at least 22 mph with bmx bike handlebars riding in as upright position as possible. I suppose it costs me range and speed, but I'm going fast enough. I get up mile long 10% grades at 15-18 mph with energetic pedaling. If you buy a big enough lifepo4 battery, range will seldom be an issue, unless you ride more than 25 miles. At 48 v hills shouldn't be much of a problem unless they are real killers. Most ordinary state roads don't get all that steep. Residential streets can get real steep though, and driveways steeper still. But a 500-800 watt motor at 48v will go up some pretty steep stuff easy.

As the others say, it does matter, just as much as with a regular bike. But you can buy enough motor and battery to not give a damn. And it doesn't take the biggest motor either, just a medium one like the 9 continents, golden, Aotema, or clyte 400 series will do fine. If you want to go superlight, and ride more like a normal bike, using the motor only for hills, then the low watt motor and small size battery make it important to stay aero. A regular ebike is so efficient to start with, that I don't worry too much about increasing it. 10 cents power takes me 20 miles so I'm satisfied for efficiency.

 

[northernmike]

You can always improve your aerodynamics with spandex.

Seriously, you're worried about wind resistance on an Electra Townie?

Don't be!

Be worried about COMFORT.

When it gets too windy to ride comfortably, get some better goggles or a shielded helmet. The measures you will need to take to reduce wind resistance will probably NOT be to your liking, if the Townie is your ride of choice!

 

[DanEL]

Thanks for all the advice everybody. Just wanted to let you all know I greatly appreciate it. I'm looking over your advice and have a few more questions. I'm just doing a little more research so I can ask more intelligent questions!

p.s. I don't have a Townie yet. It's just one of the bikes I am considering.

 

[morph999]

I saw nomad's nine continent motor. If you like torque, it's got great torque. Takes off like a rocket almost especially if you are under 200 lbs. If you want speed, you'll have to go with a 5303 but if you only want 25 mph then you could put 60v on a nine continent and get that.

I e-mailed ebikes.ca about putting a 2806 nine continent on a 26" rim and they said they would do that so you might consider that. The 2806 is a little faster than the 2807 with almost the same torque so you might consider going that route. They'll put it on whatever rim you want but it'll cost you about $70 to do it.

If I were you and wanted a nine continent, I'd get the 2806 version on a 26" rim. I bet it'd go at least 28 mph and with 60v probably 33 mph.

 

[pwbset]

I said it once and I'll say it again, but then I'll bow out... for the hills of Pittsburgh you're seriously going to want a 5304/5305 or a way overvolted/amped 4011/4013 or a metal gear 72v Bafang etc. Anything less is going to leave you wanting for more I promise you. Get a hold of Lenk... he'll tell you.

Good luck and have fun. Post pictures of your build.

 

[Patriot]

Well, I don't know about the 04/05 models, but with my 5303 today, I noticed my top speed jumped up from 37 to 39mph as soon as I got into a tuck.

Don't think I was seein' things either.

 

[Lenk42602]

Hey Dan
Good to see another local!!!!!

I live in Oakmont, just a few miles north of Pittsburgh. If you are interested in getting together and discussing ebikes, or need any help, or want to check out my set up, feel free to contact me. I am friends with another ebiker here in Pittsburgh; we generally get a few sunday rides in together a onth once the weather warms up. Haven't been on the sphere in a while - school + work full time....

Anyway, like I said, feel free to hit me up if you want to see some e-machines before you plunk down some cashola...

peace,

Len

 

[kazbluesky]

I agree with pwbset,

I have a nine continents kit and love it. It makes an excellent 1st ebike which does everything really well. Mine at 48v and 22amps will go 30mph with me sitting up normally, it will even go up most reasonable inclines BUT anything steep and you'll be pedaling HARD. Very VERY HARD. Hills yup. Up mountains? I honestly dont think so.......

 

[dogman dan]

Well yeah, if the grades are above 10% or if they go further than a mile at a time, a big overvolted motor or a gearmotor is what is needed. I have to pedal hard to get up the mile of 10% that I have on the way home. By the time it's 5% I can opt out of pedaling, but I will really slow down, to like 10 mph. It's all relative to what you need or want. I still say that if over 30 mph is wanted, or 30 mph up steep hills, a gas powered motorcycle or scooter is the way to go unless you have serious money, and want to build your own battery. Currently, the majority of ready to ride stuff on the market is really aimed at 48v max.

But if a nice asssist on up to 10% grades is all you need and you aren't wanting performance beyond 15 mph up a hill, you don't need anything all that special. A smaller wheel size can help with grades too, though it may cost a bit of speed on the flat. A smaller wheel will have more torque, but a differet winding motor will run more efficiently at a slower speed. The fast winding will lose efficiency on hills when it slows down. So if it's hilly, a slower motor may be better. The slower motor will be more efficient at a slower speed, but the price is a slower top speed. Like morph found out, you need to pick your speed, and get the right motor in the right size rim. If you want lots of speed, get ready to spend lots of money. But if 15-25 mph is all you want, that gets pretty easy and not more than $1500 to get.

 

[nomad85]

I agree with pwbset,

I have a nine continents kit and love it. It makes an excellent 1st ebike which does everything really well. Mine at 48v and 22amps will go 30mph with me sitting up normally, it will even go up most reasonable inclines BUT anything steep and you'll be pedaling HARD. Very VERY HARD. Hills yup. Up mountains? I honestly dont think so.......

I have to disagree with you here, I don't think it takes 22 amps to go 30mph(I also see a peak of 22 amps, but its during acceleration, not at top speed). My bike currently has no chain and I can get up any hill in my area at over 16 mph, usually over 20 mph, granted I live in Indiana, so not to many hills, but I do go up a few steep ones(8-9%) and never have to pedal.

 

[CoffeeLuke]

Living with the rain.I opt for lots of resistance.I get wetter waiting at red lights.

 

[Doctorbass]

I think that to represent how wind affect ebike speed this graph is a good exemple that show that the relationship between speed and power isn't linear but more exponential due to wind resistance...

Doc

 

[northernmike]

Doc, how was that chart generated?

 

[Doctorbass]

Doc, how was that chart generated?

I rassembled every data on the web bout mtb power vs speed and put them in Excel. I had not data for bike faster than 80kmh :lol: .. so i used the tendency curve to rassemble every point data and used the prospective curve to simulate the same slope increase...

These data correspond exactly to a heavy ebike like mine and the one that many crazy members here!

at 82km/h, the power requiered on the battery is the same as the one in the Lowell long ride video.. around 3000W for 82km/h ( compared using many true data on many video of ebike...

Doc

here is the file i use for my Drag ebike calculation setup:

 

[kazbluesky]

Ummm Nomad85 maybe you're right. I'm over 250pounds (last time I checked) for a normal sized chap maybe the motor will get you up steep hills. To be honest i'm kind of confused when people say 10% grades and things like that. 1 in 4, 1 in 3, 1 in 6, these grades I understand and can see in my head eg for every 1 foot climbed you have to travel 6 feet. The steepest my bike will go with me on it is 1 in 4. 1 in 3 is too much for my bike and there are a couple of inclines I have to go up to go to work where I really need to pedal hard to keep her going.

The amp thing , Im sure you are right. I dont have an amp meter on my bike. I do know I can get up to 46 km (I think that's about 30mph ) on my 700c bike while sitting up normally - and that seems waaaaay fast enough for a bicycle. I do wish it could carry me up those couple of inclines that it can't manage now and I read that maybe a few more amps might enable me to do that (hence the mod of the extra solder inside the controller that I'm going to try when my anderson connectors arrive) hopefully in the next day or 2.

Whatever though, it is a great kit. One thing that might be worth thinking about is that Ampedbikes were able to get me a rear wheel version and what with my weight and the hills I go up and down I'm glad my motor is on the back. Maybe Ebikes.ca do a rear wheel now too. Whichever though, the motor is a nice one.

 

[nomad85]

Ummm Nomad85 maybe you're right. I'm over 250pounds (last time I checked) for a normal sized chap maybe the motor will get you up steep hills. To be honest i'm kind of confused when people say 10% grades and things like that. 1 in 4, 1 in 3, 1 in 6, these grades I understand and can see in my head eg for every 1 foot climbed you have to travel 6 feet. The steepest my bike will go with me on it is 1 in 4. 1 in 3 is too much for my bike and there are a couple of inclines I have to go up to go to work where I really need to pedal hard to keep her going.

I used google earth and divided the rise by the run to get the % grade.

I bet its got as much to do with the 700c wheel as the extra weight. Larger wheels go faster, but are not as good at climbing, or acceleration.
I am also modifying my controller, I don't know if I want to solder the shunt, as I don't know how much the fets can handle, if you do solder the shunt, I would recommended using a Watts up meter to see how much you increased it, I wouldn't go past 25-30 amps. You might get the performance increase you want from shortening the wires and installing better connectors. I have already changed the phases connectors(but I haven't shortened it yet) and it performs noticeably better. I am going to remove the phase wires from the controller and install some 12g silicone wire in their place, and do the same to the battery wires. Then I will shorten the wires from the motor as much as possible to reduce the losses in its thinner wire(I have not interest in rewiring the motor...) I expect this will further increase the acceleration and hill climbing.

 

[dogman dan]

Weight would make a big difference on hill climbing. I weigh 180 so I find I climb pretty good with an ordinary brushless hub on 36v. And I do pedal hard on the real steep ones. 10% is not very steep, 1 foot up for 10 feet forward.

 

[nomad85]

Weight would make a big difference on hill climbing. I weigh 180 so I find I climb pretty good with an ordinary brushless hub on 36v. And I do pedal hard on the real steep ones. 10% is not very steep, 1 foot up for 10 feet forward.

It's steep if you don't have a motor