Leaf / leafmotor / leafbike high efficiency 1500w motor

[neptronix]

Lowering the rear or raising the front will increase the rake angle which should make any bike more stable at speed but turn left/right slower i.e. you will have to input more motion into the handlebars to get the bike to turn.

Not bad, you kind of want a powerful upright bike to be like that anyway.
I would bet changing handlebar width would countercorrect for that.

Not sure where I am headed next but one option is to take my Schwinn Axum 29er frame and put a 24" wheel with a Leaf motor in it in the rear and a 26" wheel on the front. I also have a crank that has very short crank arms that I would install.

You'll have a hard time keeping the front wheel on the ground even with a 26" leaf at above 4kw. Whatever geometry alteration you make, make sure it allows you to lean on the handlebars so you can baby nudge the throttle.

Right now it has a 26" rear wheel with a Leaf motor in it and a 29" front wheel. I plan to leave it like that until I get a chance to try it for a little while. Motor/wheel mounted, still need to mount the controller and battery plus wire everything up...to be continued .

I'd recommend you move the battery as far forward as possible to help counterbalance the wheelie power of this motor.

 

[amberwolf]

I've never heard of anyone doing that with a DD hub in my time here.

If you mean, running ATF in it, Burtie did that a bit over a decade ago here:

Good! Someone finally oil cooled a hubbie!! HS3540

Very many folks have burned coils, very few have demagnetized magnets, according to the reports we see on the sphere. No, they just cook them enough for the epoxy to weaken. Burning up windings while being oblivious to what the motor is telling them is evidence of nothing. It's definitely not...

endless-sphere.com

I recall other posts but the search isn't really helping find them quickly enough, so I don't have links or know what the specific results were.

 

[Bullfrog]

Not bad, you kind of want a powerful upright bike to be like that anyway.
I would bet changing handlebar width would countercorrect for that.



You'll have a hard time keeping the front wheel on the ground even with a 26" leaf at above 4kw. Whatever geometry alteration you make, make sure it allows you to lean on the handlebars so you can baby nudge the throttle.



I'd recommend you move the battery as far forward as possible to help counterbalance the wheelie power of this motor.

Personally, I prefer a head tube angle of ~70 degrees. It gives me enough stability but also makes it where I can turn the bike left and right relatively quickly. Old School Mountain Bikes and most cruiser bikes had roughly a 70 degree head tube angle but the newer stuff is more slack and usually between 60-65 degrees.

More info on head tube angle and how it affects handling here: Bicycle Geometry Explained! - blog.jans.com

One thing I really like about my bike with a MAC motor is with a 14s6p 52v triangle battery mounted in the front frame triangle is the weight distribution...it is almost 50% front and 50% rear since the MAC is pretty light. My Leaf motor (bare motor weighs 16.2 lbs is fairly heavy in the rear and light in the front so even though I haven't ridden it yet, I am concerned about how it is going to handle.

 

[Bullfrog]

If you mean, running ATF in it, Burtie did that a bit over a decade ago here:

Good! Someone finally oil cooled a hubbie!! HS3540

Very many folks have burned coils, very few have demagnetized magnets, according to the reports we see on the sphere. No, they just cook them enough for the epoxy to weaken. Burning up windings while being oblivious to what the motor is telling them is evidence of nothing. It's definitely not...

endless-sphere.com

I recall other posts but the search isn't really helping find them quickly enough, so I don't have links or know what the specific results were.

Thank You .

 

[Bullfrog]

Anybody running a 24" bicycle tire on the rear, what tire are you using?

I have been eyeing the Schwalbe Pick-Up 24x2.6" and the Maxxis Hookworm 24x2.5" but I'd be interested in any other suggestions...my bike doesn't leave the pavement .

Thanks.

 

[ebike4healthandfitness]

Very interesting the discussion of .27mm laminations vs. .35mm laminations.

IMHO you will probably be more likely to see .27mm laminations on direct drives with 27mm (or 28mm) wide stators before you see them on motors with 35mm wide stators.

For one thing motors with 35mm wide stators (when used with frames having 135mm rear spacing) need to be coupled with low end pedal drive trains (e.g. 7 speed or even 6 speed freewheel). That means a low end pre-built ebike.

Secondly, the low end (7 speed or 6 speed) pedal drive train (on the 35mm wide stator motor) means you smallest rear cog will likely be a 14T. This 14T top gear means your pedal top speed at cadence of 90 rpm will be too low for most unless a large diameter rear wheel is chosen....and we all know the larger the diameter of the wheel the less the benefit of thinner laminations.

Lastly, the reduction in cogging from thinner laminations will mostly likely be more desirable on lower power 27mm (or 28mm) wide stator ebikes because these type of ebikes are more likely to be pedaled on human power alone than heavier high power ebikes using a 35mm wide stator.

 

[amberwolf]

When I used to use 24" on CrazyBike2, I used generic clones of the Hookworm and they worked pretty well. Was very sticky for traction (I don't mind sacrificing lifespan for that), and was thick enough to help with flat prevention, along with my other usual layering. They're what I rode on in the SpookyTooth "Death Races" down on the kart track in Tucson back then.

I think I had one of the real HW on there and it was better.

 

[neptronix]

0.27mm lams don't benefit >20" wheels very much unfortunately, and the main efficiency loss in 27mm stators is their high proportion of end turn loss to stator width ratio.

I found using a 52-60T chainring and a 7 speed freewheel with 11t rear gears ( yes, you can still buy these ) was the key to high pedaling speed on the leaf. Could pedal up to a max of 40mph on 26 x 2.2" tires.

 

[ebike4healthandfitness]

Neptronix,

Good point about the large chainring combined with 11T 7 speed freewheel.

With that noted, I have never seen a pre-built ebike (even a low end one) not use a Shimano freewheel when it comes to 7 speed.

And the only way to get 11T for 7 speed freewheel (not 7 speed cassette) is to go aftermarket for the freewheel. (All Shimano 7 speed freewheel I have seen in the last two decades have had 14T as top gear).

P.S. Shimano did at one time make a 11T 7 speed freewheel but these were discontinued in the early 2000's.

 

[neptronix]

DNP freewheels with 11T are tolerable but obviously the best choice is a vintage shimano with 11T if you can find it.

Leaf makes a casette version of the motor, one side has a 14mm axle, the other 12mm. Due to the weaker axle i wouldn't recommend this for high power builds.

 

[ebike4healthandfitness]

Leaf makes a casette version of the motor, one side has a 14mm axle, the other 12mm. Due to the weaker axle i wouldn't recommend this for high power builds.

I didn't know there was a cassette version. Anyway, checking the leaf bike listings I see it requires 137mm drop out spacing as compared to the 135mm drop out spacing for the freewheel version.

I could be wrong but I don't think a lot of OEMs would want to use a 137mm hub in a 135mm frame. This because the hub will not sit completely parallel in the drop outs. This combined with the fact a lot of ebike frames are aluminum rather than steel makes me think it would not be accepted.

I suppose the OEM could always make a aluminium frame with 137mm rear drop outs but then they become essentially married to only one supplier.

 

[neptronix]

Just 1mm of stretch on each side of the dropouts, not a big deal.

MAC is 138mm and people have been running them forever on aluminum frames, myself included, it works!

 

[ebike4healthandfitness]

MAC is 138mm and people have been running them forever on aluminum frames, myself included, it works!

I looked everywhere and the only spec I could find for the Mac motor in both freewheel and cassette was 135mm.




Even the ebikes.ca spoke calculator lists 135mm for the GMAC (Ebikes.ca spoke calculator here --> Online Spoke Calculator for Hubmotors and Ebikes )

Yes, I know DIYers spread aluminum frames (and also complain of the hub not sitting parallel in drop outs) but it is not right to do this.

 

[neptronix]

i'm referring to the original mac from 2008 - maybe 2012.
I see they list a 138mm option and 135mm option these days.

What i'm saying is 1.5mm on each dropout isn't much bend, no real force needed, no reports of issues from ~1mm of bend, consider how long a lever the chainstay is. A hardtail aluminum bike will flex more than that under normal operating conditions.

Don't worry about 137mm at all, if you want <11T chain sprockets so you don't have to run a huge chainring like i did, and won't push more than 3000w, and use 2 torque arms, i think the cassette version could work.

 

[ebike4healthandfitness]

i'm referring to the original mac from 2008 - maybe 2012.
I see they list a 138mm option and 135mm option these days.

I can't find a 138mm anywhere. It appears to me MAC redesigned the motor to 135mm for both freewheel and cassette.

Really 138mm makes no sense and apparently MAC agrees with this.

 

[neptronix]

Quite possibly the older version i was mentioning:
750W hub motor For Sale | MAC Motor

138mm was needed to support a 7 speed freewheel back then i think,

 

[E-HP]

Quite possibly the older version i was mentioning:
750W hub motor For Sale | MAC Motor

138mm was needed to support a 7 speed freewheel back then i think,

I don’t think I’ve seen any “135mm” hub motors that will fit into a 135mm dropout without spreading the dropouts due to the required washers (not sure about the all axle motors). On both my old MXUS and Leaf, a third washer was needed for 7 speed freewheel clearance, which is why I switched to 6 speed.

 

[Bullfrog]

Is there a minimum/maximum spoke angle that shouldn't be exceeded when lacing a wheel with a one cross pattern? The Grin Tech spoke calculator link below specifies the acute (less than 90 degrees) angle between the spoke and the rim.

I asked the question differently in a different thread but figured the angle may be more informative than the difference in the OD of the motor spoke circle and the ID of the rim i.e ERD.

You can find the angle for any configuration using the Grin Tech Spoke Length Calculator:

Online Spoke Calculator for Hubmotors and Ebikes

Our handy spoke length calculator allows for easy calculation of spoke length for custom builds - and is the only one of its kind to include paired spoke holes in the flange as is common with many large diameter hub motors. It also creates an automatic side view drawing of the laced wheel and...

ebikes.ca

I'd like to use a one cross pattern but it may not be feasible with some motor/rim combinations. My inexperienced wild guess is you don't want to go smaller than 45 degrees, hopefully somebody with more lacing experience than me will chime in .

 

[E-HP]

What is acceptable spoke angle?

It’s dependent on the rim you choose, and specifically the spoke holes.

 

[Bullfrog]

What is acceptable spoke angle?

It’s dependent on the rim you choose, and specifically the spoke holes.

True, thanks for the link.

Via the link, Chalo said "Usually cross-1 lacing works with hub motors on 26 inch wheels. Usually radial lacing is required for 20 inch wheels." and I agree. I guess there are just too many variables to give a specific answer .

Guess I'll stick with my plan to sue a 24" rim with my Leaf motor.

 

[Bullfrog]

Does anyone have a set of side plates/covers for a Leaf 1,500w motor they are willing to give me...I'll pay for the shipping.

I want to do some experiments using NACA ducts in an attempt to increase the airflow through my Leaf motor...to see if I can keep it below ~130C at ~40 mph continuously/stead state.

Thanks

 

[neptronix]

I drilled holes in mine in ~2014 and proved that with some mild air cooling i could sustain 40mph indefinitely.

The motor is >85% efficient still at 40mph ( ~2000W ) so there isn't a serious heat problem at that speed.

Ferrofluid would be adequate over drilling holes in the motor for this purpose.

 

[neptronix]

 

[ebike4healthandfitness]

the main efficiency loss in 27mm stators is their high proportion of end turn loss to stator width ratio.

What you are saying makes me wonder how much stator diameter could be reduced on a motor with 35mm stators before the efficiency loss from the decreasing diameter (of the stator) becomes more than the end turn loss on the 27mm stator?

 

[ebike4healthandfitness]

Regarding what I wrote in post #2756, I actually think there is a good chance for 35mm stator making it to .27mm laminations first and here is why:

148mm x 12mm thru axle.

148 x 12mm thru axle allows for 6mm more room on the hub compared to 135mm and 142 x 12mm. Since the current leaf bike 7 speed cassette hub (31mm length HG freehub) is 2mm over budget (at 137mm o.l.d.) the switch to 148mm x 12mm boost using the 4mm longer 8 speed to 11 speed 35mm length HG freehub just fits.

In the mtn bike world boost has taken over. Furthermore I see a lot of ebikes with 20" x 3+" tires which works with boost.

So IMHO it looks like boost for leaf bike is the way forward.