Hill climbing motor recommendations

[LegendLength]

I've been reading the forums for the past few weeks trying to learn as much as possible before starting my first e-bike build.

I already have a mountain bike with aluminum frame. It's nice and light and would like to electrify it for riding around trails in my local mountainous area.

My next step is to choose a 26 inch hub motor for it. Can anyone recommend a suitable motor? Or any links to previous discussions (my searches came up fruitless searching for 'torque' or 'hill climbing').

I don't care about top speed at all, 15 mph would be more than acceptable. I would prefer a non-geared hub motor for quiet operation but if a geared is necessary I can live with that. Range is also not an issue, 10 miles is fine. Low weight would be nice though for the rocky, steep tracks I wish to ride. I weigh about 170 pounds.

Bike specifications:

- Bike is a Gary Fisher Marlin. Front and rear disc brakes. Front suspension (80 mm travel). 27 Gears, 9 on the back wheel (I believe this will be an issue). Index shift gears.

 

[llile]

I've been reading the forums for the past few weeks trying to learn as much as possible before starting my first e-bike build.

I already have a mountain bike with aluminum frame. It's nice and light and would like to electrify it for riding around trails in my local mountainous area.

My next step is to choose a 26 inch hub motor for it. Can anyone recommend a suitable motor? Or any links to previous discussions (my searches came up fruitless searching for 'torque' or 'hill climbing').

I don't care about top speed at all, 15 mph would be more than acceptable. I would prefer a non-geared hub motor for quiet operation but if a geared is necessary I can live with that. Range is also not an issue, 10 miles is fine. Low weight would be nice though for the rocky, steep tracks I wish to ride. I weigh about 170 pounds.

Bike specifications:

- Bike is a Gary Fisher Marlin. Front and rear disc brakes. Front suspension (80 mm travel). 27 Gears, 9 on the back wheel (I believe this will be an issue). Index shift gears.

Wow, that looks like a nice bike!

Don't try to electrify an aluminum bike. The dropouts may fail. In fact, cheap bikes actually make great E-bikes! Steel is the right material for your fork, and with a motor, weight is not an issue. Heck, you'll be hauling around 40 LBS of batteries and motor, minimum, who cares about shaving off a few grams? What you pay for in expensive bike components is light weight. Why add 40 lbs to an expensive, lightweight super-bike? Keep that wonderful, beautiful aluminum bike for your completely human powered rides! Get yourself a relatively cheap steel bike for your E-Bike, and have a second bike. Considering the cost of the motors and stuff, the bike is a relatively cheap part of the system!

Now, the achilles heel of hub motors is hill performance. If you are in the mountains, then you have some serious hills. Look at a slower hub motor, rather than a fast one.

Consider electryfying the front hub rather than the rear. Why? Keep it simple. The rear already has a lot of gears and chains and stuff. The front has none of that stuff in the way. You already paid for (when you buy your steel bike) all that rear deraiileiur stuff, why throw it out and buy another one? Also, weight distribution. Bikes like weight distributed evenly, not all hanging on one end or the other. Get a rear rack for batteries, or even better a triangular battery int he frame, and a front motor, then when you haul a case of beer on the rear rack you won't be popping wheelies.

Consider front disk brakes. You have a more powerful system, and you'll be coasting down those mountain hills like a rock with extra weight, make sure you ahve really good front brakes. Rear brakes are less important, but they need to be in good order.

The best motor for hill climbing is called a Stokemonkey. DOn't get excited though, it is designed to fit on the Xtracycle, or could be hacked onto other bikes. Unless you plan to weld, or plan to own an Xtracycle, it probably won't work for you.

--Lawrence

 

[LegendLength]

Thanks llile.

I'm considering using the BCM V2-T 600 W motor:



In conjunction with a LiFePO4 36 V 10 Ah battery that setup would add about 20 pounds.

The motor seems expensive (600 usd) but fairly well suited for what I want. I will have to do some more research on adding torque arms to my aluminum dropouts. Is it feasible or is that type of torque out of the question for aluminum? I would love to be able to just bolt on some torque arms rather that doing any kind of metalwork but from some of the threads I've read so far it doesn't look good.

 

[Beavinator]

If you want my advice go with a X5304 Crystalyte. I have one on my Aluminum Specialized Enduro Pro and it works amazingly well! I went with 72V 20Ah of LiFePo4 headway cells and the thing is awesome! I live on a hill that is so steep most people dont even walk up it. My bike goes up it at 45kmh in the steepest part. It goes 65 kmh on the flat which is about as fast as I like to go on a bike.

 

[Ypedal]

My view on this.. the aluminum frame is ok with a rear motor, and the BMC is a good choice as long as you don't jump, if you keep the tires mostly planted ( small stuff is ok.. but not major drops.. ) .. the geared hubs run well at moderate to slow speeds and are fairly quiet ( as in.. you hear them.. but just barely ) unlike a cyclone 500w that you can hear from a distance and sounds like a sick cat in heat.

36v is a nice boost, 48v is better...

unless you want an electric motorcycle and throw away the pedals.. an X5 is overkill..

 

[Beavinator]

You may say that the X5 is overkill but I sure dont agree with that. It is so nice to have the torque if you do a lot of hill climbing! I couldn`t imagine having anything less at times even the X5 seems barely adequate!

 

[dogman dan]

The x5 will get up those hills, because at 75v and 40 amps it IS a motorcycle.

If you want a BIKE that can climb a fairly steep hill trail, then the BMC is a good choice, but you do have to be carefull about big drops, or overvolting, or overheating if your climate is hot.

For a direct drive hubmotor that climbs, look for ones with slower windings, like the crystalyte 4011. My fave is not avaliable nowdays in the US, a 9 continent in 2810 winding. I motor right up 15% all the time on mine with that slow winding. It's not more torque, but it's torque I can use for a continous hour at 5-20 mph as I ride up steep hills. I think there is a 2809 motor avaliable in AU, if you live that ways.

I've done the 5304 thing, and didn't like that heavy a wheel when riding really rough trails. I find the 2810 much nicer with 10 pounds less hub weight. Plus, I don't need a huge expensive battery. A slower wind motor can climb great at a mere 48v and 25 amp controller.

likely you will need to go to 7 speed or less on the rear cluster, so you may have to change derailurs too to have it index right.

 

[MadRhino]

...I've done the 5304 thing, and didn't like that heavy a wheel when riding really rough trails...

Yep, I had the same problem. I had to upgrade the rear shock and set a much higher progressive spring load, before it started to feel plush on the rough terrain. My limited experience with it (I weight 180pd), is that you need about 40% damping increase to compensate the weight of a Clyte X5 in your wheel, and that can be achieved only with the best bicycle suspension components. That can cost as much as the motor itself.

Then, for the lower speed efficiency, the 5304 will never make it, for it is too fast winding. I'm building the 2nd with a 5306, on a bike that has the very best suspension system, we'll see. The 3rd is on its way already, awaiting the new N series Clyte that is about the same weight as the 9C. I'd like to try the 2810, but it is nowhere to be found now.

 

[LegendLength]

The Crystalyte 5304 sounds good for both power and price but the weight is too much at 24 pounds. The 4011 is a great price ($180) but I'm worried about it's power of only 200 W.

I like the Nine Continent 2807 at $219. Would that be ok for steepish off-road hills at 36 volts with soft pedaling?

I won't be doing any large jumps or drop-offs. Just trail riding for fun and a bit of fitness. I just want to be able to climb the rough, hilly firetrails we have without having the motor stall all the time. This a sample photo of the type of terrain:

 

[MadRhino]

...I just want to be able to climb the rough, hilly firetrails we have without having the motor stall all the time.

You need a slow winding motor, no matter which one, buy the one that you can afford. Then you need a combination of battery and controller that will feed it the voltage to correspond your desired speed, and the max Amp that the chosen motor is known to take safely.

A slow winding motor would do about 20mph top speed at 36v. If it is not enough for your need, you just feed it with 48v and it will do 30mph, and at 72v it will do 45 and so on. Then, a 9C is known to safely take 40A at lower voltage and 35A at high voltage, so your controller should be chosen accordingly. A Clyte is heavy, but will stand more Amp and is known to be able to safely take 50A and up. Almost every motor has a review on ES, and many were tested at high power, so it is easy to know their limits.

Rough climbing is the most demanding task from a hub motor, because you can't drive fast enough in rough terrain, to attain good efficiency of all fast (even medium) windings. Poor efficiency means that most of the power you feed is transformed into heat instead of climbing force. That is why you need a slow motor, the slower that you can find will be the better. Adding voltage to gain speed is not a problem, overvolting will not melt your motor, exceeding the Amp that it can take will.

 

[dogman dan]

No it won't. (the 2807) You could just overvolt it, and running 72v at 40 amps, you'll get up the hills allright. 2500 watts will do it I assure you. But you will have absolutely no low speed throttle controll, and will be going over the handlebars unless you can REALLY ride. You'd always be going too fast for comfort, or having too much power when you blip the throttle.

A 2807 running on 36v 25 amps, will bog down on the hills above 8%, then overheat as you flog the motor at too low a rotation speed for the winding.

The 4011 though, can take a hell of a lot more amps than 200. I wouldn't hesitate one bit to put a 48v 35 amp controller on one. That would get you peaks of possibly 1800 watts, and for sure you will see 1500. Just monitor the temp of the axle on the 2011 when climbing hard, (or any motor for that matter) and try to keep that axle temp below 180-200F .

If you can tolerate the weight of a 5300 series clyte, I do agree for serious trail riding you want the 5306, or like some have done run the 5304 in a smaller rim to give the same kind of higher torqe, lower speed performance.

Personally, the time I pinch flatted my rear tire on a big rock 4 miles from the car was the last time I wanted to run my 5304 in 24" rim. It was just pounding the crap out of the tires. Big chunks of tread would dissapear every single ride. We have some trails here that compare to a road paved with razor blades.

It's too bad nobody is marketing the 9c 2810 anymore. I really do love mine for dirt riding at 48v. I can grind up steep hills at 5 mph, and only bother to pedal if I stall compeltely. Never had a single flat out on the trail with the 15 pound motor. 20 mph top speed at 48v.

 

[Ypedal]

The clyte 4 series can take 1000w all day long.. my norco Chaos has a 409 in a 20" wheel at 100v 40 amps = 4000w peak and not even drilled for air cooling but i cruise at full throttle on the flats most of the time at 50 km/h or so..

Volts x Amps = Watts

So at any given voltage, times the maximum amps of the controller you plan to use will result in max watts available... at full throttle the motor will only draw what it needs at it's maximum rpm and as you hit a hill the motor will draw more amps and slow down a little bit, if the hill is steep enough the motor will draw as many amps as the controller will allow and slow down some more.. at a certain point if it's steep enough the motor will stall and all the watts being used from the battery turn into heat...

Smaller diameter wheels make a very big difference with hub motors, 20" wheels at high voltage are where the gold is at.. a lame setup at 36v in a 26" wheel can climb like a champ if laced in a 20" and over-volted to make up the rpm difference..

An X5304 in a 20" at 100v and 80 amps is unstoppable...

 

[biohazardman]

The big heavy 53xx motors with a smallish 20-24 inch wheel seem to be the best hub motors for long hill climbing and Justin took his accross Canada so they will do the mountians. I have the BMC V2S 600W and @52V it is quite good on the hills but heats up rather quickly if I don't pedal to help and keep up speed. I toasted my stock controller letting the motor only pull me and a loaded trailer up a steep hill not much more than half mile long. So you need to pay attention and be kind for things to last with the BMC. Others have commented on individual motors that they have experience also. Check my sig out for more details.

 

[dogman dan]

trail riding on rough fire roads, MTB trails, etc. I keep thinking you'll be happier with a 4011. You won't need so much raw power if the motor is wound slow.

So 1000 watts all day will work great. 48v battery, 35 amp controller, 4011 in 26" wheel. Ebikes-ca to get it. Not knocking the small wheel idea, just saying buy a slow wind and you can keep the 26" wheel.

If you like bmx frames, and 20" wheels, that's a different thing. I like big diameter wheels to ride on the rough stuff. they roll up the rock steps better.

Here's some vid of my "slow" 2810 motor riding some local trails. Climbs like a dang squirrel with that 9c 2810 on 48v. Has about 1000 watts peak power on the CA. 25 amp controller. http://www.youtube.com/watch?v=r5IBcK_puKI

 

[MadRhino]

Beautifull trail Dogman!!! I am amazed, at how different terrain that you have, as compared to mine. It is really both extremes, I believe that, if a single motor would ride a year with you, and then a year with me, it would prove to be all conditions proof.

This desert trail must be hard on any motor, I can feel the heat only watching this vid. The only thing missing there, was a petrified cow skull, and a pothole with a sign: 'Last water for one hundred miles'.

 

[LI-ghtcycle]

I must defer to Dogman on this, but I wanted to say, although steel is generally stronger, there are several of us who have used aluminum with much success, only very few use aluminum forks, and with double torque arms (I would have double torque arms if I ran a front hub motor regardless if it was steel or not) and one thing to think about if you're going to climb hills a lot, when you're climbing something really steep, and you have most of the weight on the back (your body weight, batteries cargo, etc.) the front will loose some traction as apposed to the rear.

I have never used a front hub, nothing against them, but it always seemed to me that having the power to the rear wheel makes the most sense, if it was that great, then the 2WD trials motorcycles would be all the rage, and they have never made it into production because they didn't have any real practical use.

I have had a rear geared hub motor in an aluminum Nishiki frame with no problems, however if I have a choice I stick with a good quality frame in Cro-Mo since you can still buy several premium bikes in steel, (specialized, giant, trek, etc,) I think there is something to be said for steel and E-Bikes that are being made to carry 2-3x the weight they were designed to.

My personal preference is Trek, but depending how hard you push it (or how gentle you are) you can use most any frame. Steel bends when aluminum breaks, so there is definite advantage, but a good example of an aluminum frame taking abuse, I had my latest build loaded with gear for touring (bike weight alone) at 110 lbs, and nothing looks any worse for the wear (Muddy Fox Xernt 700c Hybrid bike).

Just make sure that you don't skimp on the battery, you will kick yourself if you spend $500 on something that "will work" when just spending $600 would have given you a battery that will not be taxed to the limit which means it will last longer and give you better performance.

90% of the performance if these bikes is made possible or severely hindered depending on the battery IMHO.

 

[dogman dan]

I think he already figured on a rear hub. I have rode steep trails with front hubs, both geared and DD. Geared front hub was nice at times, since you could pedal in a low gear and have effective 2wd. But when the grade gets above 10% on dirt, the front hub would just spin when you really needed it.

So I consider a rear motor mandatory for dirt now. One exception, a front hub would be good on a flat terrain beach bike.

One nice thing about NM, is I can drive about 80 miles, meet up with Wineboyrider, and go riding on logging and firebreak roads through the forest. Only found the time for it once last summer, but my slow wind dd motor did fine on the 15% grade roads near Cloudcroft.

Emory pass in the Gila is my favorite though, miles of paved hairpin turns on 10% grade. Some vid of that in my youtube.

 

[SoSauty]

Go for a BaFang 8Fun climber, get the code 14 (14 wind). It'll pull you up 10% hills with 48V and run 20mph. Skip the front wheel hubs, not safe w/ aluminum forks. $160$ Seel cell man in new sales section of ES.

 

[LI-ghtcycle]

Go for a BaFang 8Fun climber, get the code 14 (14 wind). It'll pull you up 10% hills with 48V and run 20mph. Skip the front wheel hubs, not safe w/ aluminum forks. $160$ Seel cell man in new sales section of ES.

Is that 20 MPH up the 10%, or just it will climb 10% and go 20 MPH on the flat?

 

[dogman dan]

I doub't that it's 20 mph up the steeps. But 15 mph up 10% is definitely plausible. For how long is the issue for me though, the slow wind dd motors work best in my climate.

 

[Alan B]

I think saw a mention that member "methods" is getting a batch of 9c slow wind motors in. Those would be a good choice for this project.

A rear 6 or 7 gear set should fit. Not enough room for 9. The derailleur may be okay, but the indexer will probably need changing. They aren't expensive.

It will need a good torque arm, or a pair of them.

I'm doing a similar build for a commuter here with the 9c (regular wind).

 

[dogman dan]

Really? I've been hoping somebody with $$ would get into the slow wind 9c biz. Jason just told me the other day he could order a batch for spring, but only pre paid. So no way I could do it.

To me, the 2810 9 continent motor is the perfect climber. Sure, it may bog down to 5 mph on extreme steeps, but it won't overheat so fast if you do. It's got a slow top speed, but for me 20 mph is fast enough. Hyena has some 2809 motors in AU, that sound interesting. That may be the ultimate street bike winding. Not quite so slow on 48v, yet still able to grind a hill at 10 mph for miles.

 

[FMB42]

This is a very informative thread.

My rear DD FS MTB build is "stalled" at this point due to the concerns I have over motor selection. I'd go with a geared unit if not for the reported gear failure problems (a gear upgrade might be the answer tho). Meanwhile, I have a cheap 500w 36v Golden Motor DD unit that may or may not meet my moderate hill climbing needs (I'll swap the stock GM controller out with a 22amp Infineon unit for sure).

I'm just sorry that I didn't take advantage of the ebikekit 6x10 9C "give away" deal they offered 6 or so months ago...

 

[Ian]

I fairly sure cell_man in China does a slow wind dd basically same as a 9c 6x10 - try him?

 

[FMB42]

Thanks Ian, I'll look into your advice.