Slowest wind direct drive hub motor(s) available?

[ebike4healthandfitness]

If you want to get the very best from a hub motor, then use a small wheel

Agreed ----> https://endless-sphere.com/forums/viewtopic.php?f=3&t=108781&start=75#p1593391

-- but it will beat you up.

If the tire is narrow then yes the pressure will have to be high because the diameter is so small.

But if a wider tire can be used then the pressure can be lower.

What were you using?

 

[Balmorhea]

If you want to get the very best from a hub motor, then use a small wheel

Agreed ----> https://endless-sphere.com/forums/viewtopic.php?f=3&t=108781&start=75#p1593391

-- but it will beat you up.

If the tire is narrow then yes the pressure will have to be high because the diameter is so small.

But if a wider tire can be used then the pressure can be lower.

What were you using?

The effect I'm talking about is independent of tire size or pressure. A small diameter wheel falls deeper into dips in the surface, and rises more abruptly onto bumps and steps. If you have a hard time understanding the implications, go rent a dockless e-scooter and see what I mean.

It doesn't help that a smaller wheel has a shorter contact patch than a larger wheel, and must be run at a higher minimum pressure.

I have a bike with a 29" front hub motor wheel, and a front loading cargo bike with a 20" front hub motor wheel. Both have used 2" to 2.1" tires for as long as I've had them. They both work fine for their respective purposes, but the small wheel on the cargo bike punches me, and my groceries, a lot more fiercely and often-- even though it's slower.

Since my bikes exist to serve my needs and wants (and not to serve my hub motors), I think it's a good idea to use a wheel size that's appropriate to the job, and then configure the motor to work with the wheel.

 

[markz]

Some interesting stuff out there in ES forum land.

Tapped winding and two separate windings - https://endless-sphere.com/forums/viewtopic.php?f=2&t=3659&p=54463&hilit=dual+wind+motor#p54463

Also I know there are motors that are double wide stator - https://endless-sphere.com/forums/viewtopic.php?f=10&t=7718&p=170923&hilit=double+wide+motors#p170917

Also to ponder the 2 speed motor. Found easy enough, scroll on down.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=58490#p872847

Then there is 2wd ebike setup. What I'd like to see a nutty extravagance of is a front hub, rear hub with a mid drive ebike.




Food for thought

 

[dogman dan]

Put your 20" rear wheel on a longtail is what I did. Did not beat me up, because the seat just rocks as the wheel itself takes quite a beating. Get your ass off of over the rear wheel if you want a smoother ride.

You can buy a 20" fat bike motor wheel these days, if you want to go that route.

 

[goatman]

a 20x1.5 you feel every pebble and crack in the road, a 20x2.35 you dont, a 24x3.0 gives you 26od add a spring seat and its a nice soft ride on a hard tail if yours ass is over the tire

one of the first things i did was get rid of the tiny tire on my trike
https://endless-sphere.com/forums/viewtopic.php?f=6&t=103834&p=1563109&hilit=scorpion#p1520878

i have a bad back and theres no way i could ride with out a fat tire

https://endless-sphere.com/forums/viewtopic.php?f=6&t=103833&p=1522913&hilit=stiletto#p1517471

theyre both phaserunner bikes, high speed wheels @60v and fat tires

 

[ebike4healthandfitness]

If you want to get the very best from a hub motor, then use a small wheel

Agreed ----> https://endless-sphere.com/forums/viewtopic.php?f=3&t=108781&start=75#p1593391

-- but it will beat you up.

If the tire is narrow then yes the pressure will have to be high because the diameter is so small.

But if a wider tire can be used then the pressure can be lower.

What were you using?

The effect I'm talking about is independent of tire size or pressure. A small diameter wheel falls deeper into dips in the surface, and rises more abruptly onto bumps and steps. If you have a hard time understanding the implications, go rent a dockless e-scooter and see what I mean.

It doesn't help that a smaller wheel has a shorter contact patch than a larger wheel, and must be run at a higher minimum pressure.

I have a bike with a 29" front hub motor wheel, and a front loading cargo bike with a 20" front hub motor wheel. Both have used 2" to 2.1" tires for as long as I've had them. They both work fine for their respective purposes, but the small wheel on the cargo bike punches me, and my groceries, a lot more fiercely and often-- even though it's slower.

Yes, a small diameter wheel can fall deeper into a "dip" than a large diameter wheel but at the same time the inflation pressure of the small diameter tire can be lower if it is sufficiently wider.

The lower tire pressure would then buffer the extra shock caused by having to overcome a greater amount of step from the dip.

With that mentioned, one advantage of a taller wheel is that it can support a greater load for any given width.

 

[donn]

People manage pretty well on a range of bicycle wheel sizes. If you want to get into the weeds on efficiency, there's also the wind resistance. Rolling and wind resistance are nowhere near as significant as the issue that comes up with a hub motor's RPM range, but even there, it isn't important enough to dictate an unpleasant bicycle configuration.

 

[Balmorhea]

Yes, a small diameter wheel can fall deeper into a "dip" than a large diameter wheel but at the same time the inflation pressure of the small diameter tire can be lower if it is sufficiently wider.

The larger diameter wheel also rides cushier with lower tire pressure, and because of its longer contact patch, you can use lower pressure than a smaller wheel can.

There are rolling resistance and handling penalties that come with very fat, low pressure tires. These drawbacks are greater with smaller wheel diameter, again because of the shape of the contact patch.

Every time you compare like to like, larger wheels work better for bicycles, up to the point where they require a problematic frame layout. You can decide that optimizing for the hub motor at the cost of everything else is what you want to do, but understand that's what you're doing.

There's a sudden proliferation of fat tire folding e-bikes that only exist to be bought up by non-cyclists who don't pedal. The fact that there are no such bikes made without motor power should tell you all you need to know about them.

 

[ebike4healthandfitness]

There are rolling resistance and handling penalties that come with very fat, low pressure tires.

A wider tire doesn't have to be higher rolling resistance with poor handling.

However, there is such a thing called "Fat bike" where the goal isn't to optimize for handling or rolling resistance (on normal terrain) but rather to optimize for float over sand or slow. These bikes use rims almost as wide or as wide as the tire (which results in flattening of what would normally be a rounded tire profile) and low tire pressure in order to prevent sinking into sand or snow.

P.S. Here is an example of where good handling was achieved with a fat bike by using a much narrower rim:

https://fat-bike.com/2018/04/26-27-5-fat-bike-wheel-comparison/

We start with[/b] a Borealis Carbondale double-wall carbon set of hoops that are 50mm wide, laced to a set of Borealis hubs with a set of Maxxis Minion sneakers. This is the set of wheels that I’ll be running this summer for Camrock and Kettle Singletrack. For the first time in the last few years, my fat-bike will be my full-time mountain bike. These wheels are the missing link, where plus and fat meet.

 

[Balmorhea]

There are rolling resistance and handling penalties that come with very fat, low pressure tires.

A wider tire doesn't have to be higher rolling resistance with poor handling.

Hypothetically, you may be right. But in practice, a tire fat and soft enough to offset the ride shortcomings of a small diameter wheel has both these tradeoffs.

When 2.25" tires first appeared, I used those. When 2.5" and 2.6" tires appeared, I used those. When at long last there was a 3" MTB tire, I had a frame custom made to use it. With a little modification, I was able to fit in 3.5" tires when they came along. But there were always associated problems. In the early days around 1990, the rims were too narrow to support big tires unless they were inflated pretty hard (which kind of missed the point). By the time we got significantly over 3", the limiting factor for low tire pressure was "self-steering", or the tires' resistance to being straightened back out of a turn. It's a terrible habit for a bike that makes me not want to ride it ever.

As far as rolling resistance goes, with the same tread thickness and the same tire pressure, bigger tires have less resistance from working the rubber. But they rarely have the same pressure. Also, scrub within the contact patch increases with the size of the contact patch, and becomes a dominant source of rolling friction.

Anyway, fat tires are great, but there's no free lunch, and you can definitely have too much of this good thing. And everything good about a fat tire on a small wheel, is even better for a fat tire on a big wheel.

 

[ZeroEm]

The wider the magnets/motor 50mm vs 35mm the slower the motor is!

 

[ebike4healthandfitness]

There are rolling resistance and handling penalties that come with very fat, low pressure tires.

A wider tire doesn't have to be higher rolling resistance with poor handling.

Hypothetically, you may be right. But in practice, a tire fat and soft enough to offset the ride shortcomings of a small diameter wheel has both these tradeoffs.

The low pressure tire will always have a larger contact patch.

....but this does not always mean worse handling or higher rolling resistance. In fact usually a larger contact patch means better handling.

As far as rolling resistance goes it depends on how much the sidewall is deforming on each tire. A shorter but wider contact patch (resulting from a smaller diameter but wider tire) can actually have less sidewall deformation even if it is larger.

 

[Balmorhea]

A shorter but wider contact patch (resulting from a smaller diameter but wider tire) can actually have less sidewall deformation even if it is larger.

It has to reconcile a lot more distortion along the lengthwise axis. So it must be especially wide before tread scrub isn't a serious rolling resistance disadvantage. Sidewall deformation is a thing, but there's also the rounded tire making a compromise with the flat riding surface. The larger and softer the tire, the more scrub tends to predominate rolling resistance.

I've built custom pedal machines with as wide as 21 x 7" smooth buff ATV tires (about 20" actual diameter). They're cushy, they're relatively quiet-- but they're slow. That one was a trike, so it had sucky handling like a trike. I can't say how well it would have handled as a two wheeler, but my guess is: just okay.

 

[ebike4healthandfitness]

Balmorhea,

Earlier in the thread you described two wheel and tire combos:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=108827&start=25#p1593452

One thing I can't help but wonder about is the spokes and rim on both wheels. Can you tell me what those are ? Straight gauge or double butted spokes.....and how many of them?

Direct drive or geared hub motor?

The reason I ask is because spoke thickness and count can have an effect on ride quality (particularly in small diameter wheels which would be stiffer than large diameter wheels at the same spoke count and spoke thickness).

Also the fork design and material matters greatly as well.

 

[markz]

I don't consider tire friction a factor when I ride. Heck I've been riding with a front hub, 19" moped rim and knobby asfuck tire for motorcycle, dont talk to me about drag and friction because that mofo was a beast and loud on pavement which I rode most of the time. However I did receive in the mail a moped tire with smoother tread. Just need a new fork because the accident it widened it. Not sure exactly what form factor the headset is in for Costco fat bike. That new tire of mine might fit on my old Norco cruiser in the rear, but might buy fat fork for it. Too many choices for bicycles to put it on, all in various states of dismantledness. 700c hybrid is ready to ride 100% stock. Choices, the key for the newbies is just get out and ride.

 

[Balmorhea]

Balmorhea,

Earlier in the thread you described two wheel and tire combos:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=108827&start=25#p1593452

One thing i can't help but wonder about is the spokes and rim on both wheels. Can you tell me what those are?

Also direct drive or geared hub motor?

29" hub motor wheel is a Kris Holm 700C rim (38mm wide) laced to a Leaf 6T 1500W direct drive motor with 13-14ga Sapim spokes. Cross-1 lacing.

20" hub motor wheel is an Alex Supra RX rim (34mm wide) laced to a Crystalyte 5305 direct drive motor with 14ga Sapim spokes. Radial lacing.

 

[ebike4healthandfitness]

Balmorhea,

Earlier in the thread you described two wheel and tire combos:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=108827&start=25#p1593452

One thing i can't help but wonder about is the spokes and rim on both wheels. Can you tell me what those are?

Also direct drive or geared hub motor?

29" hub motor wheel is a Kris Holm 700C rim (38mm wide) laced to a Leaf 6T 1500W direct drive motor with 13-14ga Sapim spokes. Cross-1 lacing.

20" hub motor wheel is an Alex Supra RX rim (34mm wide) laced to a Crystalyte 5305 direct drive motor with 14ga Sapim spokes. Radial lacing.

Spoke count was the same?

Also can you describe the forks?

 

[Balmorhea]

Spoke count was the same?

What forks were being used?

Both 36 spokes. The 29er uses the stock Redline Monocog rigid chromoly fork. It's a generic unicrown fork with slightly beefier than normal dropouts.

https://endless-sphere.com/forums/viewtopic.php?t=26444&start=175#p1505427

The cargo bike uses a Sunlite chromoly 20" recumbent fork. It's super sturdy, but doesn't have a whole lot of tire clearance.

https://www.jbi.bike/site/product_details.php?part_number=28369

 

[ebike4healthandfitness]

Ok, so according to Leaf:

And eikes.ca spoke calculator:

https://ebikes.ca/tools/spoke-calc.html?hub=5300&pair=false&rim=20DM

Both the leaf 1500W and Clyte 5305 make a dishless front wheel.

Both motors also have the ~same flange diameter.

That means the wheel with the smallest diameter rim will definitely be the stiffest since both wheels have 36 spokes with the main body of the spoke on both wheels having the same thickness (14 gauge).

That will affect the ride quality independent of differences in tires.

P.S. The fork on the 20" cargo bike also looks it would ride worse than the one on the 29er:

https://www.jbi.bike/site/product_details.php?part_number=28369

https://www.redlinebicycles.com/monocog.html

 

[ZeroEm]

Grin is using 32 Spoke stock rim options, not sure how many motors are supporting this now.

 

[markz]

32H
Grin all axle
https://ebikes.ca/product-info/grin-products/all-axle-hub-motor.html

32H - My guess is smaller wheel, still achieve 1X lace. For the recumbents, folder market. However, grin states

Uses 32 Spoke Holes for vastly more in stock rim options

 

[ebike4healthandfitness]

Some more info on that Grin All axle motor:

https://ebikes.ca/product-info/grin-products/all-axle-hub-motor.html

updated from N35 to N40 grade magnets. Stronger magnets allow the motor to produce more torque for hill climbing with less heat loss, but they also increase the drag of the motor when riding without power. [/u]In our original design we erred on having lower rolling drag because at the time we felt this was more important than efficiency on hill climbs, but the Virtual Electronic Freewheeling feature in the Phaserunner/Baserunner controllers has shifted the balance and we switched to a higher strength magnet.

As a result the V2 motors spin about 5% slower than the V1 models. They have about 10% more drag torque but they can also climb hills with 10% less heat generation.

I wonder what happens if they further upgraded to N45 or N52 magnets?

 

[markz]

I wonder what happens if they further upgraded to N45 or N52 magnets?

More cost for the consumer.

motor to produce more torque for hill climbing with less heat loss, but they also increase the drag of the motor when riding without power.

motors spin about 5% slower

So say 10% slower

10% more drag torque but they can also climb hills with 10% less heat generation.

So say 15 or 20% more drag torque and 15-20% less heat.

 

[ebike4healthandfitness]

I did plug in some comparisons (using the ebikes.ca simulator) using Grin V1 vs. Grin V2.....both fast and slow winds.....and I also used 26" wheels and 20" wheels.

Keeping the wheel size and controller (either Phaserunner or Baserunner) constant the V2 does indeed have a little bit slower top speed but it climbs faster using less energy per km in process.

I wonder what happens if the stator teeth were made deeper and/or thinner? This to increase copper fill.

What would the effect be on N40 magnets and magnets that were even stronger than N40?

Do stronger magnets benefit more from increased copper mass than weaker magnets?

 

[markz]

What about the gap between the magnets?

You could analyze it forever and get a percentage point here or there.

The bottom line, it doesnt matter! Just get out there and ride. Stop analyzing and make the purchases now.