YASA was founded in 2009, a spin out from Oxford University following the PhD of founder and still CTO, Dr Tim Woolmer.
"Over the decades that followed both of these technologies were explored. But despite the potential for weight reduction, smaller size, shorter axle length and increased torque, it was the difficulty in manufacturing the axial flux technology that limited its commercial viability, because the motor could not be made by stacking laminations, as with radial machines."
"The breakthrough innovation came by segmenting the axial flux motor in discrete "pole-pieces", so the motor could be manufactured using Soft Magnetic Composite material.
SMC can be pressed at low cost into a wide variety of 3D shapes. This removed the need for the complex laminations, overcoming the major manufacturing challenge of the axial flux machine."
"In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
The opening of this facility boosts YASA’s manufacturing capacity, setting new benchmarks in e-motor technology and quality, and enabling production to scale beyond 25,000 units per year."
This is awesome. Lighter motors also make electric flight more viable
In an ICE, the same load is less visible because most energy gets wasted as heat. This is also why cold weather seems to affect EV range more.
> No wonder electrics don't sell well in the US. People weigh more, you're basically saying that leaving grandma at home, is a "game changer".
Even in the US, your average grandma weighs less than 2-300kg :D
If we could indeed leave "grandma" home, that would make things better.
And they don't sell well in the US because of oil lobbying and think tanks whose sole goal is to make you buy more oil.
250kg weapons = ~20 small dogs
Instead of technological advancements of EV motors, we can immediately use existing pharmaceutical tech (Ozempic, GLP-1) to immediately deliver weight reduction to cars. However, this will be immediately offset by the increase in weight of weapons carried, thanks to Jevons Paradox.
https://electrek.co/2023/04/27/saab-engineers-develop-secret...
I think large drones will be another place where a downsized version of this motor will make a huge difference, assuming the power scales nicely with size.
There are probably a range of application where in-wheel makes perfect sense.
Do e-bikes really need significantly more power than they have? They already run arguably dangerously fast for their application. Is efficiency not the primary target there?
The lower weight would be definitely welcome, my ebike is comically heavy compared to a normal one and sometimes I have to carry it up flights of stairs (some German railway overpasses, grr).
Also in scooters it could fit in the wheel (since the wheel is tiny and has to spin quite quickly - no reduction gear needed vs a bike with 26-28" rims) allowing a simpler design and cost savings. But maybe in scooters they're already using in-wheel motors, I'm a bit ignorant there.
Oddly, a very large majority of current fully suspended e-bikes with rear cargo racks have those racks unsprung, which suggests that most e-bike manufacturers don’t actually care about the handling of anything other than their pure e-MTBs.
I'm always interested to hear about the latest in lighter and possibly more powerful and torque-y e-bike motors.
Ref: https://www.cyclinganalytics.com/blog/2018/06/how-does-your-...
From https://lammotor.com/yasa-axial-flux-motor/
the shape is due to the change to the motor layout: https://www.thedrive.com/news/why-axial-flux-motors-are-a-bi...
By using motors at each wheel you'd eliminate the need for a differential, saving a good 40-50kg or so. Of course, if you kept the drive shafts and put the motor and reduction box in the middle, you'd be able to use inboard brakes and save a lot of unsprung weight!
Wouldn't that make it worse or just ... different. Before this then the unsprung weight wouldn't have had a motor in there and now it does. Increasing the unsprung weight doesn't seem a like a good thing.
They claim, this compounding effect works out to basically double the effective weight saving from battery and motor.
ie if you start with saving 50kg on motor, and 50kg on battery, you end up saving 200kg over all. Still only about 10% of a typical electric car.
Nitpick: You can have a lighter motor, but you're never going to have a significantly more efficient motor because existing EV motor systems are already 95% efficient or better. The electric motor is an old and refined technology.
For light weight vehicles on the other hand, it might be.
So yeah, weight reduction on EVs is great.
I think people are overlooking that the announcement is for a performance motor meant for the performance market at the moment because that is what the backers of YASA are most interested in because it has the highest margins and prestige. Also not mentioned is the efficiency from the simpler production line.
My impression from what I know is we are looking at an impact equivalent to direct injection engines; not revolutionary, but a major advancement of one component that has significant and consequential effects.
Tesla (I know) claimed a 30kg (?) weight loss on their Cybertruck (I know) just from moving their 12V systems to 48V, allowing for lighter cables at lower currents. Not all such potential is untapped, and my hunch is that there is more to be had with structural battery integration, battery cooling, and high voltage wiring.
The next innovation we need is Aerial refueling[1] for electric planes. High density swappable batteries and high altitude wind/solar plants that can swap batteries mid air. Perhaps some billionaire will develop a large fleet of these to service all flights! If no western billionaires, we just have to wait for China to develop this tech.
On the ground: swapping batteries is faster, and batteries are cheaper than planes or drones. You want the expensive part back in the air as soon as possible so you don't need as many of them. On the whole this probably also simplifies logistics: in civilian aviation airport space is limited, in wartime it's easier to transport one hundred drones and two hundred battery packs to the frontline than to transport two hundred drones
A laser over 10W has safety implications. This is 50,000 lasers all shining on the same plane.
Given your collectors are only going to be say 50% efficient, you're likely going to dumping enough wasted energy into the wings to melt the aircraft - not sure what dumping 3MW of heat energy into a plane would do over an hour, but I suspect it would stat to melt in a few seconds if you're lucky (otherwise your passengers would start getting very toasty)
At 3MW for an hour that's not a great amount of electricity that's needed - at 10c/kWh it's $300 an hour. You don't need fancy things like fusion to generate that. In the UK alone Solar is currently (in November) generating 600 times that - plus domestic installations.
Also planes would not have to wait for a tug to pull back from the gate, which improves turnaround times for the airline.
Not very feasible, but an option that has been thought through.
I guess there’s a system that’s gated to track dependent technologies, to track improvements and what they’ll enable.
Not really. EV's are very heavy from non-motor weight. A Model Y weighs ~4300 lbs. A motor that is 75 lbs lighter is a 1.7% savings. That's not nothing, but I wouldn't say "significant". You can do better by swapping for fancy wheels or eliminating some of the glass roof.
And really this is true up and down the electric vehicle world. Weight-sensitive applications are always going to be completely dominated by battery weight. Making the motor smaller just isn't going to move the needle.
Basically this is good tech without an application, which is why it's having to tell itself with links like this.
But yeah, EVs seem weird except for racing reasons perhaps.
What I can’t figure out is how they dissipate the heat - double digits kw per kg is crazy.
The more of the energy going into moving the vehicle, the less heat the motor has to handle.
And there is no way this is 99% efficient.
So my question still applies. Even 98% is 1kw/kg, or 1kj/sec. or around 3C rise per second assuming the mass is 100% nice clean copper (it isn’t). Everything else will be worse.
Not even counting increasing losses with temperature, it will be a molten puddle pretty quick at that rate without some major active cooling.
The YASA axial flux motors benefit from much shorter windings and direct oil cooling which gives an unparalleled performance proposition.
A 200kW peak-power radial motor, run continuously, might typically give 50% of peak power between 80 and 100kW, as a result of thermal limitations. In contrast, a 200kW YASA motor runs continuously at 150kW thanks to the improved high-thermal-contact cooling that oil offers.
Unfortunately I feel much less safe in a Fiat 500 when a significant portion of cars in the road weigh nearly 3 tonnes and perhaps can't even see me. I suspect most people are in SUVs because they're the pragmatic trade off between safety and convenience, not because they were hoping for excellent performance.
Everyone who can will naturally choose "defect" unless there's some sort of external coordination mechanism.
This is why the first performance mod that most people put on their cars is an adjustable coil over suspension. Dropping the car down by an inch or 2 changes has just as much of an impact as shedding some weight.
Ironically, most people put lift kits on Jeeps but that also usually comes with widening the wheel base and putting on larger wheels/tires.
Increased height makes for increased ground clearance and improved break over angle. Sway bars are another suspension component that's great for reducing body roll on road at speed, but reduces articulation and ground contact off road. Differential lockers also negatively impact turning radius, and cause tire chirp, wear, and oversteer under throttle on road, while increasing traction off road.
What's silly is daily driving an off road vehicle on road, especially if you never take it off road.
That's not ironic. That's just caring more about the looks and you like that look. And looks > handling for that person
This is a blanket statement and completely untrue. Good driving experience is directly correlated to TRACTION, not just weight. And traction isn't just a function of weight - it also is affected by center of gravity, friction between the wheels and the road. Traction is what gives you the perception of being in control of the car.
I used to own two cars of the exact same model - one petrol and one diesel. The petrol is lighter in weight, about 100+ kgs lighter than the diesel variant. And the driving experience on that is slightly scary especially on roads with strong winds. In fact, it is so light that if you drive over tiny puddles or rumbles strips, the car will sway sideways. The diesel always feels more planted because it is front-heavy, thus adding more traction to the front wheels (both are FWDs). I always prefer the diesel for longer drives because of the heft and confidence it provides.
If we take a Tesla model 3, I believe it weighs 1611kg, and the motor shows up at 80kg if you google it (no idea if this is correct). This YASA motor by comparison weighs 14kg. So, this would drop the vehicle weight by 66kg out of 1611, so that's a 4% saving.
But torque and power were never the limiting factor for an EV. You would only benefit on a track, and if you're taking a model Y there...
It’s a little sad to me that fundamental innovations in electromechanical engineering like this get just a few million in investment, yet if this had been yet another derivative software startup with “AI” in the pitch, they’d probably have 10x+ or more investments being thrown at them.
That is ever more special
EV motors are already lightweight. The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger.
Not a significant efficiency improvement for vehicles that weigh over 3000lbs (or double that for many EVs).
Every little bit helps, but this isn’t a game changer.
It can make cars cheaper, or longer range, or faster, or any number of other designs based on what the manufacturer is looking for.
But to OP's point about flight - stacking 6 Tesla motors is not an option. Stacking 6 of these YASA motors? Much less weight.
You’re reading their marketing material.
A Model 3 motor is already well under 150lbs, unless you start including ancillaries like the inverter and power transmission parts.
They’re not dropping “a buck fifty” from typical EV motors.
Even if motors were literally weightless and mass-less, EVs would weigh more than ICE cars.
It's like making a more efficient CPU for your phone when all the power is eaten up by the cell-modem, screen and RAM. People wonder where the practical battery life gains are and theyre miniscule in practice
(That's 28 pounds, 1000 hp peak, 470+ hp sustained.)
The 40% improvement is actually 36% and is versus the previous model of the same company.
Basically all EVs have small and light motors compared to ICEs or compared to the battery. Shaving off ten pounds there is irrelevant.
Wheel hub motors are obviously bad, for harshness reasons, but if you could have a motor like this weighing 1-2 kg, and put one on each wheel, that'd be okay.
Power-wise this would be okay if things are linear. 26 kW per wheel sustained power output is more than enough for a light car. The question is what torque a scaled-down machine can be expected to have.
30kW sustained/60 kW per wheel peak power is easily enough even for large passenger vehicles. Sustained could take 3 ton vehicle up a 10% grade at 120 km/h.
or about the same as a small dog
I wonder if we defined peak as sustained peak over 100 milliseconds, or some more meaningful number, what that would do to the claims. You aren't really generating meaningful torque over 1 microsecond.
Sounds like it could be more important for drones?
Not sure why the negatives in this thread (maybe too many folks hold TSLA stock?), this is properly awesome (r)evolution.
What would make you think we wouldn't sell our tech crown jewels also? (throwing in our grandparents and children to sweeten the deal).
The primary company link is from a UK subsidiary of Mercedes-Benz and is (almost) fully metric (the fundemental units US weights are officially defined with respect to (for more than a century now)).
See: https://yasa.com/news/yasa-smashes-own-unofficial-power-dens...
Earlier in the summer YASA achieved 550kW (738bhp) from a 13.1kg version of its new axial flux prototype motor, equating to an unofficial power density world record of 42kW/kg
Now latest testing of an even lighter 12.7kg version on a more powerful dynamometer has shattered this record, with a staggering 750kW (>1000bhp) short-term peak rating, resulting in a new unofficial power density record of 59kW/kg
You can tell, because a proper Brit would have given it as 2 stone, not 28 pound.
( Of course Scottish Britains used 16 Scottish pounds for a Scottish stone ).
The point being that 'precious' metals used a different weight measure altogether .. (common lead often used a 12 pound stone).
Such a fun system.
It didn't help that pre-Revolutionary France was a political Frankenstein stitched together from dozens of regions with completely different history (Celtic Brittany, Flemish Dunkirk, Germanic Alsace, Provencal South, Catalan Roussillon, Italian Nice) and thus very different local standards of everything, including measurements and law.
Unification of units removed a massive constraint on international trade and engineering. Except the US and Myanmar, of course... it is so frustrating to order anything from Myanmar e-shops, I must say. But Myanmar is at least promising to move on.
Most people usually understand what it means something to be 20 meters, 5kg or 2 liters intuitively. Like, when I hear that something is 60m tall I intuitively think if it as 20 story apartment building and don't benefit from the extra info about how this is like 18 elephants stacked on each other.
Because people in the south don’t even know the imperial system… it’s bad. They say things like “Take the road there yonder and when you see the white church, turn right, go a ways until you get to the dirt road…”
Anything outside of what they have with them, they don’t have a clue or can’t imagine it accurately. Small dog reference, there’s millions of Americans with a small dog so most just looked to their pooch when this came up. Same as if you were to say something like 50 cars. They would look outside to their Toyota Corolla and imagine 50 of them. It’s like talking to grown toddlers sometimes but that have full grown emotional states not under control. Not everyone is like this but a good 50-60% of Americans are. Just look for the Lululemon.
[1] The chart below shows how this works. The blue line at the top shows the “surplus” of corporations: corporate income minus expenses and net investment. We know this as corporate “free cash flow.” The red line shows combined “surplus” of other sectors: government, households, and foreign trading partners – in excess of their consumption and net investment. It’s negative, so in aggregate, they’re running a deficit. That deficit is the mirror image of the corporate surplus. This isn’t an accident. It’s just accounting (I’ve excluded a few tiny items for clarity): https://www.hussmanfunds.com/comment/mc251028/
I'm in my 40s. Never did it, never going to.
And with your bank balance instantly available on the computer in your pocket, and transactions posted in near-real-time, why would you need to worry about balancing it?
At the gym I use the pound plates and not the kilo ones. I intuitively know what the difference between 135 and 225 lbs feels like, and I don't have that same intution for kg.
All that said, I don't find the "small dog" types of analogies for weight very useful. Why not just use the same number of characters (or less) to give the weight in the other popular unit?
Newspapers in my country don't make these silly comparisons.
But yeah, to be fair, when hearing about Starship I had to look up our TV tower height to identify whether Starship is taller or not. It disappointed me that it's not.
Yeah, height is easier to grasp when correlating in terms of x story apartment buildings.
Our problems don’t stem from lack of freedom, they stem from too much of it.
No guns, but they have solar panels, batteries, EVs, etc.
In this case, what is actually considered to be a small dog? To me it would be something that is close to the size of a cat but since it's about 13kg, it can't be that small, so that's more like a medium dog (I'm not certain, but I have a feeling that if you lay out things statistically this is what you would end up with). On the other hand, 13kg is very easy to get, that's just 13 liters of water, and it's quite easy to make a mental image for both volume and weight "feeling" that way.
American units feel so impressive and random, it is the reason they always add those weird comparisons but often they make it even worse.
> Large boulder the size of a small boulder is completely blocking east-bound lane Highway 145 mm78 at Silverpick Rd
I’d say 25-50 lbs would be medium, small below that and large above.
Aaaand for various fittings for plumbers.
After switching to the metric system ('70-80s) some things are still measures in imperial units. If you slice some ham at a counter in a grocery store, it's in grams. You then turn around and get a pound of apples and a gallon of milk. Nuts are in grams, and soda is in liters. Also the body weight tends to be in pounds. Tools are both metric and imperial. Speeds and distances though, thank god, are metric.
All this is just kinda there and everyone's OK with it, but it is an epic mess if you think about it.
But how many footballs a small dog weighs?
Which kind of football: the British or the US-American one? :-)
Mercedes‑Benz Group AG (MBG.DE) – ~ US$62 billion
Revenue - €153.2 billion (2023)
Production output - 2,491,600
--
Tesla:
Production output - 1,773,443 vehicles (2024)
Revenue - US$97.7 billion (2024)
--
Maybe Tesla is just hillariously overvalued and MBG AG can afford them once the hype bubble implodes.
It would enable Tesla to diversify operations move into applying its technology on a mass-market basis to hybrids without "damaging" the "purity" of the Tesla brand.
It would enable more marques to target specific economic bands, international markets, etc.
But no we basically have a car company that makes two cars.
"something that is not just random" ==> Probably a long way away from something in production. I wouldn't hold off on any urgent transportation needs waiting on this tech.
Of course, when consumer car efficiency increases, they won't necessarily get higher ranges because the manufacturers will instead try to downsize the battery.
So, no rare-earth magnets? And it will be cheaper than existing motors?
I have no idea, but:
I searched axial flow motor in wikipedia, and the last link is:
https://newatlas.com/technology/conifer-iron-magnet-electric...
So maybe?
I see lots of press from Yasa & Donut motors, but afaik no public pricing & relationships with select partners only.
If it isn't very good, then it might be excellent for drag races, but maybe not so many others.
Also, any power that doesn't turn into torque, is likely to be expressed as heat.
Just noticed that they are owned by mercedes benz- they will kill it accidentally. Corporate wont be able to roll it out. They will try and capture all the value and kill its potential
Motors need to be made of laminated steel sheets to reduce parasitic eddy currents. The laminations need to be thin in the direction of the direction of the flux. For radial flux motors you just punch out a shape and stack a bunch of sheets up. For axial flux you have to wind a strip: https://15658757.s21i.faiusr.com/2/ABUIABACGAAgmviFqAYozvPw-...
Each layer of that strip has a different cut in it, so its much more complicated to make. The shape and manufacturing method typically impacts efficiency; YASA avoids that by spending more money. Efficiency is an unavoidable requirement of high power density- heat is the limiting factor, and going from 98% to 96% efficient means double the heat.
The mechanical demands on the motor are also much higher- radial flux is balanced since the magnetic force pulls the rotor from opposite sides. Axial flux motors are usually one-sided, so the magnets are trying to pull the rotor and stator together with incredible force. That also makes vibrations worse. Extremely strong, expensive bearings are required to handle it. With permanent magnet rotors you need a jig to lower the rotor into place; they can't be assembled by hand. That also makes maintenance more difficult and expensive.
You can roll a spool of that material and then machine the shape out of it. I've seen this done for axial flux motors. There are other approaches as well, and the cost differences get even smaller if you throw automation at the production process. I used to believe axial flux motors were one of those oddities that won't win in the end, but now that I work with them I'm not so sure. They are at least competitive with radial flux machines.
e.g. high RPM, or high torque options over existing generators?
I think electric motors should focus on other vectors.
That being said, could this be adapted so that a 2.8lb motor produces 100 hp? That would allow putting a small motor in each wheel, thus completely eliminating axels, driveshafts, and allow recapturing the space they used to occupy. It also wouldn't significantly impact unsprung weight.
It costs 10,000 Wh to power this car.. for 12 seconds.
- Toyota-style hybrid drives could be a lot lighter, and they don’t need large batteries.
- e-bikes with tiny batteries?
- Hybrid aircraft? What if there was a battery large enough for takeoff and landing, a small motor (or pair for redundancy) for cruising and to recharge the battery, and motors and fans or propellers wherever is best from an aerodynamic perspective.
- Power tools.
chris_overseas•6h ago
defrost•6h ago
The YASA link is primary, links to test data and back story, and has more detail substance and authority.
larodi•5h ago
rtaylorgarlock•2h ago
thenthenthen•1h ago
rtaylorgarlock•13m ago
fainpul•2h ago
At this point why don't we get rid of the k prefix and write 59W/g?
Edit:
I was half joking, but various answers mention kW being standard for motors, kg being the SI unit for mass etc. All true, but as used here in a combined unit, which means "power density" it still would make sense IMO. It's not like the "59" tells you that it's a strong motor and hence you want kW to compare it to other motors. You can't, it's just a ratio (power to weigth). W/g just reads much nicer in my head. Or we could come up with a name, like for other units. Let's call it "fainpul" (short fp) for example :)
59 fp is a new record for electric motors!
samdjstephens•2h ago
kibwen•2h ago
youngtaff•2h ago
floo•1h ago
Same reason you wouldn't use m²/s³ even though that's also technically correct.