The main problem with wheel hub motors is “unsprung weight”. In order to keep the vehicle under control the weight of the wheel assembly needs to as light as possible. That includes wheels, brakes, outer part of the drive shaft and the assembly to hold all this. If you add a 20 kg motor to that wheel, it will not be able to keep the wheel on the ground at speed. All the time. Any bumps will create a momentum upwards strong enough to overcome the dampers and springs, and the wheel will shortly depart the road and then be forced back down. This will cause bad handling, it will cause excessive tyre wear, and it will cause energy loss, because of slippage, and excessive wear on the drivetrain because of uneven resistance because of the slippage. Modern EV’s have the engines directly coupled to the wheel through a simple gearbox without clutches directly through a drive shaft to the wheel. There is little to gained in transmission loss in avoiding a short drive shaft. More is to be had by designing better transmissions and more effective motors.
Transmissions for EVs can improve efficiency beyond having direct drive motors. As for batteries being able to get distances to 500 miles…we already have reached this milestone.
Hardly a game changer and definitely not a big increase in range, the only real benefit is losing the drive shafts and universal joints, it will reduce maintenance and not much else unless a tank turn is a big deal .
Wheelhub motors also need a reduction gear, a planetary gear can easily be included, but adds up to weight. It remains interessting though how this develops.
Fossil fuel reserves aren’t dwindling. However every other reason for pushing EVs is absolutely fact. To add to this EVs are actually cheaper to run and own.
Electric motors have always had a high power density, this is nothing new. Tesla's motors are already powerful "enough", what they need is smaller cheaper motors in a smaller cheaper car. Aptera tried to use them, but cooling was an issue. Moving cooling pipes hadn't really been done before.
While I agree that we are polluting the planet, I don't agree with some trying to frighten people. The earth is resilient in lots of ways. Ice melting would not not be as some say. Sea ice unless grounded is two thirds plus under water and contains lots of air. If it all melted might even lower the sea level. Trees grow better with more co2 so more uptake. Just to name a few facts. But in saying this I do look forward to a hydrogen society and low fossil fuel usage. Less wars would help immensely
Hub motors on on ebikes are very limited. If you ride your ebike only on the road then hub motors are ok but if you ride off road then hub motors create a too heavy rear end and the mid drive motor is a much better option.
Unsprung mass is a big problem in drive comfort and handling, that’s why it’s not done.
The main problem with wheel hub motors is “unsprung weight”.
In order to keep the vehicle under control the weight of the wheel assembly needs to as light as possible. That includes wheels, brakes, outer part of the drive shaft and the assembly to hold all this.
If you add a 20 kg motor to that wheel, it will not be able to keep the wheel on the ground at speed. All the time. Any bumps will create a momentum upwards strong enough to overcome the dampers and springs, and the wheel will shortly depart the road and then be forced back down. This will cause bad handling, it will cause excessive tyre wear, and it will cause energy loss, because of slippage, and excessive wear on the drivetrain because of uneven resistance because of the slippage.
Modern EV’s have the engines directly coupled to the wheel through a simple gearbox without clutches directly through a drive shaft to the wheel. There is little to gained in transmission loss in avoiding a short drive shaft. More is to be had by designing better transmissions and more effective motors.
All that unsprung weight won't help the ride and handling.
No, But vehicles simmilar to Aptera can use it in rear wheel, without front engine
Agreed. A possible solution might be to have the individual wheel motors mounted inboard, giving similar benefits without the unsprung weight.
So how does it affect the handling when just one or two fail??
Transmissions for EVs can improve efficiency beyond having direct drive motors. As for batteries being able to get distances to 500 miles…we already have reached this milestone.
Hardly a game changer and definitely not a big increase in range, the only real benefit is losing the drive shafts and universal joints, it will reduce maintenance and not much else unless a tank turn is a big deal .
Wheelhub motors also need a reduction gear, a planetary gear can easily be included, but adds up to weight.
It remains interessting though how this develops.
Fossil fuel reserves aren’t dwindling. However every other reason for pushing EVs is absolutely fact. To add to this EVs are actually cheaper to run and own.
Strange Lightyear was not mentioned, their car had this technology because of its efficiency. Sad they didn't make it to production.
Consider that hub drive could also be an easy way to convert ICE cars to Electric.
Electric motors have always had a high power density, this is nothing new. Tesla's motors are already powerful "enough", what they need is smaller cheaper motors in a smaller cheaper car. Aptera tried to use them, but cooling was an issue. Moving cooling pipes hadn't really been done before.
Unfortunately we as a species are running out of time. Experts are now talking of climate tipping points accruing by 2030, that's 5 years away.
Yes, but just to make sure, there seems to be no end in sight to the +$5 trillion annual fossil fuel subsidies. Funny doomed world we live in.
While I agree that we are polluting the planet, I don't agree with some trying to frighten people. The earth is resilient in lots of ways. Ice melting would not not be as some say. Sea ice unless grounded is two thirds plus under water and contains lots of air. If it all melted might even lower the sea level. Trees grow better with more co2 so more uptake. Just to name a few facts. But in saying this I do look forward to a hydrogen society and low fossil fuel usage. Less wars would help immensely
Stop freaking out man. There's nothing going on. Look outside ur window. Instead of at ur TV screen. The world is fine.
Hi I have a bicycle with a wheel hub motor, it has 40 newton metres of torque , with three torque settings which increases it power to a160 watts😮
Hub motors on on ebikes are very limited. If you ride your ebike only on the road then hub motors are ok but if you ride off road then hub motors create a too heavy rear end and the mid drive motor is a much better option.
This automated voice put me off!! No-one real calls the Porsche 911 "nine hundred and 11"!