Help Please - Trying to decide on what type of motor.

Hi Team,

I am new to the eBike world. I have spent a long time researching to determine what type of motor to select. It appears the more research I do, the more difficult it becomes to choose. I am trying to choose between a hub motor and an external motor that drives through the crank and uses the bikes gears. I have searched many forums and can not seem to find a clear answer. Manufactures both boast their system is more efficient. From what I can understand this appears to be the case:

Hub Motor Pros
1. Easier to install
2. Less maintenance
3. Quiet

Hub Motor Cons
1. Does not have a wide range of gears (usually none) therefore motor can not run at it's most efficient speed all of the time.
2. Once you reach the maximum speed of the motor, you just free spin the pedals.

External Motor Pros
1. Can use the gears of the bike to keep motor running at it's most efficient speed by changing gears on the bike.
2. When cruising and in top gear of the bike, motor does not need to spin as much (but surely this would require more torque). But less turns required to keep the same top end speed.
3. Smaller in size?
4. PWM controller can be internal
5. Tend to be more efficient

External Motor Cons
1. More maintenance due to extra chains etc.
2. Possibly more noise as you have to use the bike chain to drive the bike.

I believe you can rest and not have to pedal with the External Motor, but I have never seen one. So how does this work considering the chain has to move to drive the back wheel. Would'nt this force the pedals to rotate?

There is a reasonable chance that I have some things wrong or missed some points, so please let me know if this is the case so that I can use this information to assist with my decision.

Given the same motor but different voltage, 36 vs 24 means you should get better distance (speed should be the same).

I am looking for something that is 200 - 400 W. I guess 36V (going to 48V means more batteries thus more weight, 24V seems to be a bit small).

Batteries - Will certainly use either NiMH, Li, or LiPO.

I am considering using my existing bike.

My terrain does not have too many steep hills (more gentle gradients).

Any help that anyone can give me here is greatly appreciated.

Thanks in advance.

Hi WR
Here is a place in OZ with a good selection of hub motors.
http://www.users.bigpond.com/solarbbq/bikesale/bsale.htm

If you haven't any big hills i would go with a hubmotor -much simpler.
My first hubmotor was a C'Lyte 408 running at 48V 20A with lithiums and was fantastic as it was my first ebike.
But i found the e-forums and was corrupted into getting more power -which equals lazier

So i hardly pedal anymore and have a Bottom Bracket Drive which goes up hills without pedaling.

If you want to stay at the lower limits of power >400 - then an external motor would probably be the best bet for more torque -or maybe a geared hubmotor for simplicity.

Cheers
Dom[/url]

Hi Dom,

With an external drive, does this mean that the chain is running all of the time. Is this more noisy or not really noticeable? Is this more wear and tear on the equipment or not really an issue?

When changing gears with an external motor do you have to stop using the motor or just simply change gears as the motor is driving the chain all of the time. If you add assistance (prior to getting lazy ) is there an issue with how the pedals are adding more strain than the motor?

Thanks

There's also bikes like my Currie that use a chain driven motor, but connected by a second freewheel on the side opposite the rear gear cluster. In this configuration, the outboard motor is one-speed only -- like a hubmotor.

if you are mechanically inclined and know how to weld and like to build stuff, you will have more fun and be able to make a better bike with a cheap motor and chain drive. the gearing is more simple than you think. on my bike the multispeed sprocket is left as is with the pedals driving it, i welded a 65 tooth sprocket to the opposite side of the hub with the motor driving it, so when you pedal with no motor you also make the motor turn but you can barely feel it unless you try to go fast, but thats what the motor is for, i generally only pedal from a dead stop so i dont draw so many amps from the batteries. i dont have multiple gears for my motor i just chose a good gear ratio to get the best efficiency on flat ground at full speed(by full speed i mean the speed reached at any throttle setting not just full throttle, so basically just when not accelerating or going uphill), the efficiency going uphill isnt bad also because i chose such a large motor and geared it so high so even going uphill its under its rated continuous load. the efficiency will get a little lower as you lower your speed because the motor will be closer to the no load speed at a lower than full throttle voltage because of air resistance reducing in a non-linear fashion. but even then with the motor at a lower efficiency you will travel farther at lower speeds because of the much reduced air resistance. so basically if you have the tools and skills use an external motor with chain drive, if you just want something that works and is easy to put together get a hubmotor.

Hey WR
Depending on if you have a freewheel at the motor(if you go for a crank drive) the motor chain will only turn the freewheel when you pedal without e-power.

If everything is aligned well -i haven't noticed much wear over a year -same chain anyway.

It is noticeably noisy if you don't lube the chain regular.

I have an internal geared hub (Nexus8) which i have to back off the motor when changing gear -else i get the crunchies. Don't know how a normal geared bike would go. Probably the same.
If you have everything geared right -you can pedal with the motor -or not.

If you have a freewheel on the motor and crank -you can pedal like a normal bike.

Ash(forget his username) has a similar bike to what Xyster is showing from Kmart -last i read he was pretty happy with it -and he has a few hills.

I have lots of hills -and have got very lazy -else i would have stuck with the hubmotor in the wheel -they are very impressive if you haven't ridden one before.

Cheers
Dom

Hi WR. I have both a Gohub (xlyte 408) and Cyclone kit. Right now, I have to say I like the hub motor better. I'm having problem with the free wheel crank. The torque is so great on the chainring that it pulls the freewheel apart. I'm working on it. I'm going to try a smaller chainring to reduce the torque the motor puts on the freewheel. I'm also going to find a better freewheel.

The gohub is a frontwheel kit which is easy to install. I've ridden Ric's rear wheel pheonix and I'll have to admit that rear drive rides better. But I have also noticed that the rear wheel has a greater tendency to go flat because there is so much weight on the back compared to the front. It's a big pain to change a flat on a hub motor bike so it's almost worth going with a front hub motor for just this reason.

I have over 1300 miles on my go-hub kit. I use my electric bike to commute to work so the reliability is important to me. The only thing you really need to watch on a front hub is to make sure the main bolts are tight. If not, the motor torque will slowly spread out the dropouts (if you have a steel front fork).

Dom, a derailleur will allow you to change gears whilst under load without a problem.
Johndoh, I suspect you have a dodgy freewheel (some of the cheap ones slip from new) I have never had a freewheel fail with human or human and motor, I am hard on bikes and have very steep terrain.
What power is the Cyclone, what is your wattage output.

A freewheel on the cranks takes around 3 times the torque of one on the rear hub. Cheap ones really aren't up to it. If you can afford it, get a White Industries ENO freewheel.

Hi Gary -
One of the reasons i went with the Nexus is you can down/upshift while stopped -plus i'd got used to it on a previous bike.
Being able to shift under power would be good -if you can downshift in time before stopping (i kept forgetting )

I've been using a cheapo Dicta freewheel for near 2 years on both of my bikes -one powered with a 50cc motor,with zero problems.

You have to take them apart -remove a few shims tighten them back up,then back the locknut up a quarter turn or until you can just turn it freely. Then TIG the locknut to the centre bit.

A good cleanout when they sound a bit crunchy -bit of a spray of lube and they are good to go again.

I did buy an ENO just in case ($145 AU ) but it's still in the box.
Beautiful bit of kit though and would be the better altenative if you can't get someone to TIG the cheapy.

Cheers
Dom

But I have also noticed that the rear wheel has a greater tendency to go flat because there is so much weight on the back compared to the front. It's a big pain to change a flat on a hub motor bike so it's almost worth going with a front hub motor for just this reason.

Click to expand...

Sturdy tires (Maxxis Hookworms, Specialized Armadillos, etc) super-thick tubes (DH racing type), and soft kevlar liners like those below are the way to enjoy RWD without flats. I've gone over 2000 miles now without a flat on my heavy, RWD X5, plucking copious road debris bits from the rear tire along the way.
http://www.universalcycles.com/shopping/product_details.php?id=11244&category=

Hi Guys,

This is excellent help.

Short of sounding like an idiot. What exactly is a freewheel?

Thanks

You must be kidding WR -everyone has heard of a freewheel

http://www.staff-bmx.com/store/freewheels/dicta_n.html

You can get them left or right hand with different amount of teeth -they go one direction and lock in the opposite direction.

They are used in alot of bike applications -similar to a normal gear cluster on your back wheel.

You can use them on motors and cranks to make it easier to pedal.

Cheers
Dom

Thanks Dom.

Okay, I think I have decided on a Hub motor as my first motor. Easier to transition and install for my first eBike.

Found these and wondering if anyone has any experience with these.

<a href="http://www.goldenmotor.com/">http://www.goldenmotor.com/</a>

Considering 36V 500W, 36V/15AH LiPO kit. Want throttle twist rather than thumb control.

Just a thought WR, but my first ebike experiment used a twist throttle from a scooter on a mtb. I had to be careful not to roll the throttle when braking. Current setup has a thumb throttle, and I am very happy with it. However, there are two part (or half) twist throttles and also brakes that cut off the controller, both of which would have either helped or eliminated my problem.

Good thought Rassy.

Also after looking at the specs of the 500W motor, the 400W might be more efficient for my needs. Also don't want to be too tempted to ride too fast (it is not a motorbike and I would not have the correct protective gear). Also trying to avoid any suspicious constabulary checking out my >200W motor.

I have also read with hub motors the better ones have a 'freewheel???' or something similar that allows the wheel to free spin especially when going down hills, etc. Or am I simply confused.

Thanks for everyone's help it's fantastic.

Hi WindriderAU,

I have just sent my third email to goldenmotor.com over 4 weeks, and am still to receive a response. They certainly are cheap but I'm starting to think that could be a big mistake to make - if they aren't interested or capable of customer service, I would think twice about sending them my $$.

Compare the service from EV Tech (USA) or SolarBBQ (here in Oz) where I received helpful replies within a day. Sure it may cost a bit more upfront.....imagine how bad would aftersales service be with goldenmotor?

Will start a thread myself when I have placed an order so I can keep everyone here updated.

Don't know much about the golden motor -just some feedback from buyers i think mentioning the wiring was too short or something.

Were you thinking of front or rear hub?

I think SolarBBQ may only have the rear motors spoked into rims -have been meaning to get myself one of his P2B geared motors for awhile now.

The wheels spin freely -only slight drag if not powered up.

Cheers
Dom

I ordered my Cycleanalyst from ebikes.ca. Was the last thing ordered and got here to Korea thru the APO mail before all the other stuff.

They seem to have more motors now. If they would have had the stock in at the time I'd have ordered from them.

Awww - go with the 5304 or 5303 and use the Cycleanalyst to limit the current (or speed) :wink: . Their Cycleanalyst matches their controllers..

B

I ordered my Cycleanalyst from ebikes.ca. Was the last thing ordered and got here to Korea thru the APO mail before all the other stuff.

They seem to have more motors now. If they would have had the stock in at the time I'd have ordered from them.

Awww - go with the 5304 or 5303 and use the Cycleanalyst to limit the current (or speed) :wink: . Their Cycleanalyst matches their controllers..

B

I will go for a front hub motor.

I have also emailed Goldenmotor.com (twice) with no reply yet. Makes you a little nervous about parting with the hard earned cash.

Small world..

I'm bayside Melbourne too. When I get my bike back together, probably next week, you are welcome to have a ride.

36v "250w" front hub motor and a 10Ah 37v Lithium Battery.

Soon to be mounted in a Triple Clamp fork on a XC Dually.

The last step (hopefully) is to put an 11.1v lithium/nimh in series for more top speed.

I got my motor from Ebay (ruggedmachinery) who is also local. And Brett (Solarbbq) has been a great help and I wouldn't hesitate to recommend him.

Brett told me 48v was the way to go and he was right. With 36v the motor tops out at ~34kmh with pedalling.

Mark

welcome to the melbourne club!

The first thing i would do is go down to EV Vechicles at St Kilda Junction and test ride one of their hybrid electric bikes (this is a 250 w geared front hub motor). http://www.powerped.com.au/ This will give you an idea for if you do wish to go through with the conversion.

For me the ride was good, but slow, and since i could outride the electric bike on my road bike without assistance i decided to go the higher power route.

i'm in the process of building a bike with a 408 rear hub motor (purchased from Brett aka solarbbq2003 - http://www.users.bigpond.net.au/solarbbq/.)

He's helped far and above more than anyone else, I have a massive log of emails from him helping me with every question under the sun. His service is excellent and he even properly tests his stuff before he sends it - to the spec you are going to run it at. IE he tested my 72v controller at 72v to ensure it would work and found that it blew - saving me time testing it then returning it (and incurring postage costs). - VERY highly reccomend him.

I think I have just about settled on a motor.

Now need to work out batteries.

NiMH or Li-ion or LiFePo?

Thanks

Which motor?