Mid Drive or hub motor

[maxwell92036]

I have been doing a lot of lurking and searching and now I am looking for some opinions from you smart folks!

I want to add an electric motor to a mountain bike (Voodoo 29er Canzo, KHS full suspension 26 inch wheel or Surley Pugsley with either 26 inch wheels with 4 inch tires or with 29er wheels and tires. are the possible candidates)
I like the idea of a mid motor for efficiency and hill climbing but I like the simplicity of rear hub motors too.
Cyclone? Crystalyte torque motor or BMC torque motor (MAC?)
I need to climb 15 percent grades on a regular basis. I don't really need to go much faster that 25MPH.
Any feedback?

Thanks in advance!

 

[neptronix]

Welcome to the forums!

15% grades? 25mph on a flat? A 10T rear MAC motor should be able do that well on 48v-52v.

Read about experiences with the cyclone kits on here. It's a novel concept, but they're very problematic and a lot of people give up on em.

Mid drive is cool if you can fabricate the metal bits needed. But hub is 4 times easier..

 

[Tench]

I must agree, after building a cyclone which is perfect for its intended use and owning a rear hub bike aswell my current build is a mid mounted rear hub using an HS3540 running through the gears, this effectively gives me a range of gearing equivalent to a 9.5" wheel right upto 25", the best of both worlds, my build is well advanced and nearing completion. Based on the Specialized Big Hit. The advantages over a rear hub are far better weight distribution and much lower unsprung mass.
Going for a mid mount has many other benefits but is also a lot more work engineering wise than using a rear wheel mounted hub motor, i think it is also important to keep the conversion within your capabilities so it makes it to completion, with more knowledge and experience gained your builds can become more ambitious.
I think the DD rear hubs are probably not that well suited to using the 29er wheels, the efficiency at low speed would suffer due to the very low rpm's, a geared hub would be better for wheels of that size if you put it in the wheel.
The best tip i can give you is design it through to the end before you start, that way you should'nt have any major problems that cant be overcome.

Cheers Simon.

 

[maxwell92036]

Thanks for the feedback guys!
I have played around with electric motors and a gas motor for years, but I have been out of it for quite a while now. When I left the electric scene it was front brushed hub motors and SLA. OK on the flat but my hills were too much for it.
I have looked quite a bit on the forum about mid drive and I like it for the Pugsley for many reasons:

1. Ability to switch between my fat 4 inch tires or my 29er tires including high pressure tires.
2. Of course the gearing and weight and weight distribution.
3. Not having the weight of the motor in the hub.

If I go hub motor I too am leaning towards the geared hub motor for the reasons given.

I am pretty aware of the cyclone kits issues particularly in regards to mounting. I do believe the Surly Pugsley frame being steel with a big triangle and long chainstays is a good candidate for mid drive. My neighbor is quite adept at metal fabricating and welding so I have a good source to make a sturdy mount. Other than mounting the mid drive motor are their any other issues I need to be concerned with? Is the motor capable and is the controller in the kit any good?

Also I saw this mid drive kit with higher wattage's and more options than cyclone has. Is this basically the same kit? http://www.ebkit.com/index.htm

Thanks again for all the help!

 

[John in CR]

Use a hub motor as a mid-drive.

If it's long 15% grades, if you go hubmotor in-wheel, then it better be a small wheel and if your load isn't light then it better be a powerful hubbie, and you really should plan on a pair of them. I'll believe a geared hubbie can survive dependably on long 15% grades in a normal size wheel when I see a video of someone's 100th trip up. Other than a few very short (tens of yards) segments, even the road up to Pike's Peak isn't that steep and Tour de France grades don't even come close. You get above 10-12% and that's steep.

 

[AussieJester]

Other than mounting the mid drive motor are their any other issues I need to be concerned with? Is the motor capable and is the controller in the kit any good?

Noise and wear on sprockets and chains... they do make a racket if you go with anything but the 1500watt Cyclone (which has no built on reduction) If you can make mounting hardware (the kit stuff is pure garbage) to run through the bikes existing gears, you won't get a frock motor that will come close to it in climbing abilities and efficiency while doing it. If you have access to fabricator, depending on his abilities and how much your willing to spend, the other option is using an 'rc motor' tiz alot more work alot of reading and no more reliable than previous mentioned options and/or more efficient, but a hell of alot of fun, they are light with alot of power and sound better than the cyclones gear clatter...IMO

Best of luck which ever way you go, welcome to ES

KiM

 

[amberwolf]

I like the idea of a mid motor for efficiency and hill climbing but I like the simplicity of rear hub motors too.
Cyclone? Crystalyte torque motor or BMC torque motor (MAC?)
I need to climb 15 percent grades on a regular basis. I don't really need to go much faster that 25MPH.

I'd go with a combination of both, like this one:
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=34406

You might need a bigger motor than that, but maybe not, depending on how long you need higher power.

 

[maxwell92036]

Thanks for all the responses.

You sure make things tough on a guy! I am pretty sure my friend can make a very acceptable mount for the mid drive motor. I looked at the cyclone site and didn't see a 1500 watt motor. Any links?
I know what a 15 degree slope is and I know it is steep. I have even ridden a bunch of the tour de france climbs and some of my stuff is steeper than that but it isn't too long, perhaps a block or so at the most.

On another front, I have an eGo scooter that I want to revive but the controller (a blue sevcon model) is toast. Any source for one that might work with it?

Thanks again!

 

[John in CR]

you won't get a frock motor that will come close to it in climbing abilities and efficiency while doing it.

AJ,

I would have agreed with that statement before this morning. I did a 25% grade today with 350lbs of me and bike, and according to the motor test report it was somewhere above 85% efficiency, which I believe based on the barely warm motor temp after both runs up it. The 2nd included stopping halfway up and going at it from a stop. I don't think any non-frock can come close, not and do 50mph too. Of course no other frock will do it either, since few can even reach 85% peak efficiency much less 93% peak and mid to high 80's in the power band.

You'll be proud of me though, since I'm planning to ultimately use this motor as a mid-drive so I can go with a bigger but much lighter wheel.

John

 

[Beachcruzer]

John, what motor and controller are you running in that 20" wheel setup? I'm trying to spec a frocket-drive (DD hub as mid-drive) to run with 18s or 24s lipo. Looking for something that will push ~45 mph steady on the flats, and climb a 1.5-mile 10 percent grade at ~25 mph or better. Bike plus rider will be in the 250-270 lbs range. I'll be using 26" wheels but chain-drive should allow gearing equivalent to 20" or smaller.

Wondering how that wish-list compares with your real-world experience?

 

[maxwell92036]

What the frick is a frock??
Source for a 1500 watt cyclone motor?

Gracias!

 

[John in CR]

What the frick is a frock??
Source for a 1500 watt cyclone motor?

Gracias!

AJ named hubmotors Frocks, because using a hubmotor is so easy it makes you girlish and you must wear frocks (some type of dress). It started as an inside joke that spread.

 

[maxwell92036]

So when I see a bunch of people on hub motor bikes I can yell out Here come the frockers??

 

[AussieJester]

So when I see a bunch of people on hub motor bikes I can yell out Here come the frockers??

Yes you can HAHA as to when and why WiKi: Frock

A frock motor is a hub motor frequently fitted to electric bicycles.
Unlike belt or chain driven motors which can pose a hazardous entanglement risk
to those wearing long or loose garments, the hub motor is laced into the center
of the bicycle's wheel. With no fast moving parts near the rider's legs it poses
little threat to those wearing frock-like garments. Frock motors are either internally
geared or direct drive and come in various sizes depending on their power output.
They are the most common type of electric bicycle motor and are fitted to millions
of bicycles throughout China and around the world.

I seen that monster hub of yours John its a beauty, as a mid drive you
should be up near Lukes bike speed, at least in acceration ? looking
forward to seeing it mounted up and running

KiM