Rad 750wt review
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AHicks
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There's some debate about how the stock Rad 750w gear drive might be rated as it is, but there's little doubt the bigger motor Bolton is talking about is going to have more power.
The thing to keep in mind maybe, is that Rad has sold a ton of 750 watt rated bikes with few complaints regarding the power of it's motors. Not exactly justifying the difference in size between the 2 motors in question, but it is something to keep in mind when making a buying decision.
A lot of people, myself included, believe that at the price point RAD bikes are offered, with what most believe is very good support and warranty backing them, the bikes can be purchased, ridden a bit, and modified doing whatever it takes to make the bike suitable for YOUR purposes - and still be very affordable compared to most competition.
Not sure of your question regarding less power than a smaller motor?
The thing to keep in mind maybe, is that Rad has sold a ton of 750 watt rated bikes with few complaints regarding the power of it's motors. Not exactly justifying the difference in size between the 2 motors in question, but it is something to keep in mind when making a buying decision.
A lot of people, myself included, believe that at the price point RAD bikes are offered, with what most believe is very good support and warranty backing them, the bikes can be purchased, ridden a bit, and modified doing whatever it takes to make the bike suitable for YOUR purposes - and still be very affordable compared to most competition.
Not sure of your question regarding less power than a smaller motor?
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D
Deleted member 4210
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How can anyone know what a real 750 watt motor should feel like, if they are buying on line, and not trying it first versus other 750 watt motor ebikes ? There should not be any complaints in that situation bc there is no experience or expectation. They do however have quite a few complaints on other forums and lots of issues when in hilly areas or someone rides a friend's ebike and finds its more powerful than their Rad. Kyle Bolton made the video about the size difference and power bc he knows for a fact it's a weaker motor than most 500 watt or 750 watt motors powered at 48 volts. He does sell upgrade kits to the Rad. But he is honest in his videos and he does otherwise promote the Rad. It's not a bad ebike for the money, but it's very heavy, and the components are fairly low end such as you would get on an ebike kit via Alibaba or Aliexpress. They do a nice job of spiffing all of it up, and it's attractive marketing they do on line. The real headache will be when issues arise and service is needed. If you are very handy and give yourself at least a B grade trouble shooting electronics and mechanical problems, and can explain those well to a phone rep or won't be able to see your ebike first hand, and if you don't mind receiving various parts that may or may not resolve the issue the first go around and have lots of patience waiting days or weeks for a resolution then maybe the Rad is a doable ebike. And if you don't mind a one size fits many frame, and willing to take the risk yourinseam is too short, etc. Or what the ride comfort might be like, then again it may be worth the lower price.
It's difficult for consumers to judge long term value, so it's common to choose based on lower price when buying sight unseen and on line. Consumers often rationalize the low price as being less risky, but it might actually cost more if the ebike runs out to not be what is desired, then has to be sold, and a new one bought in a short period of time.
What you dont hear about is the ebikes that are shipped back to Rad. Not too many people are willing to admit they made a mistake on a purchase like that. So the tendency is to keep quiet and just move on. Only a very small percentage of ebike buyers ever post on this forum or any forum. Keep that in mind when seeking comfort for your decision or reinforcement that your decision makes sense. The Rad is priced at the low end of a market that mostly runs from $1500 to $7000. Many more models are produced above the $2500 price point that are reviewed here at EBR than below it. So it's a relatively low expectation purchase versus someone who is plunking down $3000 or more. It's also not a 'move up' ebike unless your first purchase was a really bad mistake of a $500 ebike from Amazon.
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smorgasbord
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Rad has two different "750 watt" hub motors: one is direct drive and one is geared. You can see which model has which motor here: https://www.radpowerbikes.com/pages/compare and you can read RadPower's own take on the differences here: https://blog.radpowerbikes.com/guide-to-electric-bike-motors
These two "750 watt" hub motors have different profiles when riding. Rad claims the geared motor (used in RadRover, for instance) puts out 80Nm of torque, while the direct drive motor (used in the RadCity, for instance), reportedly only puts out 40Nm. And if one is also looking at bikes with mid-drive motors, that's a different ballgame as well, as torque gets multiplied through the chain gearing. Different motors with different construction and different controllers and different batteries will perform differently. If one looks at the automotive world, no-one measures a motor based on its power consumption, but on what torque and horsepower it puts out. And, a motor that is consuming less power may nonetheless output more torque to get you up a hill better/faster!
Here's an interesting article on The Myth of ebike wattage. In essence, motors can be driven, within limits of course, at varying power levels, mostly depending on the controller used. Until motors are rated by torque and horsepower produced (at some specified RPMs), comparisons will remain confusing.
RadPower bikes do put 750 watts into their motors, so they're not lying. But, for 2018 and earlier models, RadPower in their Owner's Manual warned:
Notice: It is recommended that users pay close attention and ride within the following limitations to ensure the hub motor does not overheat or become damaged from excessive loading.
For 2019, the notice was changed to: Follow the best practices listed below to help extend your range and battery life. - and included the same bullet points. Maybe they've found the motors hold up better than they thought, or maybe they though telling people to climb hills in PAS 1 or 2 would be a deal killer if people knew if before buying, or maybe something else. I rode a RadCity for 2 months and never read the manual, so I used as much power assist up the hills as I wanted. Bike seemed just as OK afterwards.
These two "750 watt" hub motors have different profiles when riding. Rad claims the geared motor (used in RadRover, for instance) puts out 80Nm of torque, while the direct drive motor (used in the RadCity, for instance), reportedly only puts out 40Nm. And if one is also looking at bikes with mid-drive motors, that's a different ballgame as well, as torque gets multiplied through the chain gearing. Different motors with different construction and different controllers and different batteries will perform differently. If one looks at the automotive world, no-one measures a motor based on its power consumption, but on what torque and horsepower it puts out. And, a motor that is consuming less power may nonetheless output more torque to get you up a hill better/faster!
Here's an interesting article on The Myth of ebike wattage. In essence, motors can be driven, within limits of course, at varying power levels, mostly depending on the controller used. Until motors are rated by torque and horsepower produced (at some specified RPMs), comparisons will remain confusing.
RadPower bikes do put 750 watts into their motors, so they're not lying. But, for 2018 and earlier models, RadPower in their Owner's Manual warned:
Notice: It is recommended that users pay close attention and ride within the following limitations to ensure the hub motor does not overheat or become damaged from excessive loading.
- Do not climb hills steeper than 15% in grade.
- Pedal to assist the motor when climbing hills and accelerating from a stop.
- Avoid sudden starts and stops.
- When climbing hills reduce the power output when possible. This can be accomplished by pedaling with the bike while in pedal assist modes 1 or 2.
- Accelerate slowly.
For 2019, the notice was changed to: Follow the best practices listed below to help extend your range and battery life. - and included the same bullet points. Maybe they've found the motors hold up better than they thought, or maybe they though telling people to climb hills in PAS 1 or 2 would be a deal killer if people knew if before buying, or maybe something else. I rode a RadCity for 2 months and never read the manual, so I used as much power assist up the hills as I wanted. Bike seemed just as OK afterwards.
maria.owenby
New Member
No hub motor can give 80 Nm torque unless they have 8 mph top speed. Unfortunately both motor manufacturers and e-bike companies love writing huge values to their spec sheet.
Hub motors even geared ones have single gear ratio. On the other hand mid-drive motors have multiple gear ratios. Mid-drive motors when need higher torque they use speed reduction gears so the speed goes down but power goes up. (The same way wind turbines work. Imagine how much power they produce even at such low speed ).
And when you don't need such power they change different gear and provide higher top speed.
On the other hand hub motors always work on single gear ratio (consider they have gears. Direct drive even don't have it). Use common sense if it is possible for a cheap hub motor to offer 20 mph top speed and also 80 Nm torque where Bosch offers only 45 or 63 Nm torque. I tried Rad and they have difficulty in climbing steep hills.
For Rad we already know their direct drive motor value is way too apreciated as the supplier Shengyi don't even have 750w direct drive motor. But I can justify their logic here. They use peak power as motor value. Not the nominal output.
Hub motors even geared ones have single gear ratio. On the other hand mid-drive motors have multiple gear ratios. Mid-drive motors when need higher torque they use speed reduction gears so the speed goes down but power goes up. (The same way wind turbines work. Imagine how much power they produce even at such low speed ).
And when you don't need such power they change different gear and provide higher top speed.
On the other hand hub motors always work on single gear ratio (consider they have gears. Direct drive even don't have it). Use common sense if it is possible for a cheap hub motor to offer 20 mph top speed and also 80 Nm torque where Bosch offers only 45 or 63 Nm torque. I tried Rad and they have difficulty in climbing steep hills.
For Rad we already know their direct drive motor value is way too apreciated as the supplier Shengyi don't even have 750w direct drive motor. But I can justify their logic here. They use peak power as motor value. Not the nominal output.
AHicks
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Though I agree with much of what you have to say, this comment may not be the "last word" on this piece :
"No hub motor can give 80 Nm torque unless they have 8 mph top speed. "
The Grin motor simulater is a very highly regarded tool that allows you to plug in a lot of common variables to see what happens. Here is a simulation of the also well thought of MAC 12t gear driven rear hub motor. As can be seen when fed 48 volts using a 35 amp controller, it not only produces well in excess of 80Nm of torque, it's also very capable of speeds in excess of 20mph...
MAC sells their motors with different windings. You can buy them for speed, or you can buy them for torque - at the expense of speed. Which is right for you can be chosen pretty easily through the use of a tool like Grin's.
https://www.ebikes.ca/tools/simulator.html?motor=MMAC12T&batt=B4814_EZ&cont=C35&axis=mph
I do acknowledge the amount of torque available does decrease as speed increases. The bigger point is there are gear driven rear hub motors with a LOT of torque capable of speeds in excess of 20mph.
"No hub motor can give 80 Nm torque unless they have 8 mph top speed. "
The Grin motor simulater is a very highly regarded tool that allows you to plug in a lot of common variables to see what happens. Here is a simulation of the also well thought of MAC 12t gear driven rear hub motor. As can be seen when fed 48 volts using a 35 amp controller, it not only produces well in excess of 80Nm of torque, it's also very capable of speeds in excess of 20mph...
MAC sells their motors with different windings. You can buy them for speed, or you can buy them for torque - at the expense of speed. Which is right for you can be chosen pretty easily through the use of a tool like Grin's.
https://www.ebikes.ca/tools/simulator.html?motor=MMAC12T&batt=B4814_EZ&cont=C35&axis=mph
I do acknowledge the amount of torque available does decrease as speed increases. The bigger point is there are gear driven rear hub motors with a LOT of torque capable of speeds in excess of 20mph.
smorgasbord
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Just as with automobiles, one has to specify the RPM at which torque and hp values are given. All electric motors produce the most torque at zero rpms - just ask any Tesla owner, for instance. The specs given for torque from all manufacturers are not at the maximum rpm of the motor, so the comment about a maximum 8mph doesn't really apply. The chart AHicks referenced shows that.
Here is Bosch's spec: https://www.bosch-ebike.com/us/products/drive-units/ (click on "Technical Details"). The box says: "Maximum possible drive torque (Nm)." BTW, this chart includes the new 2020 motors.
As I said earlier, comparing hub drive to mid-drive is not apples to apples, regardless of cost of the motor. 80Nm of torque applied at the hub is different than 80Nm of torque applied at the chain, which of course goes through the bike's chain/gearing. There are pros and cons to both hub and mid-drive motors, and for hubs to both direct and geared motors. No one style is universally better for all bicycling applications.
Have you found any hub drive that didn't have difficultly climbing steep hills? Considering the hub motor is in a single gear and can do at least 20mph, try putting a mid-drive bike in high gear and see how much trouble it has climbing that same hill. Probably would be even worse, regardless of cost.
Here is Bosch's spec: https://www.bosch-ebike.com/us/products/drive-units/ (click on "Technical Details"). The box says: "Maximum possible drive torque (Nm)." BTW, this chart includes the new 2020 motors.
As I said earlier, comparing hub drive to mid-drive is not apples to apples, regardless of cost of the motor. 80Nm of torque applied at the hub is different than 80Nm of torque applied at the chain, which of course goes through the bike's chain/gearing. There are pros and cons to both hub and mid-drive motors, and for hubs to both direct and geared motors. No one style is universally better for all bicycling applications.
Have you found any hub drive that didn't have difficultly climbing steep hills? Considering the hub motor is in a single gear and can do at least 20mph, try putting a mid-drive bike in high gear and see how much trouble it has climbing that same hill. Probably would be even worse, regardless of cost.
smorgasbord
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Just a note that there are quite a few places in North America from which you can either test ride or rent RadPower bikes for a day (or longer). My wife and I did an impulse rental at the beach while on a weekend vacation, which we loved so much we went back there a couple weeks later and rented the bikes for 2 months, taking them home with us. We had a blast doing all sorts of rides, and at the end, while my wife was pretty content with the RadCity Step-Thru (if I'd just upgrade the brakes to hydraulic), I convinced her that we should buy better bikes. That said, I could see where for many people and uses RadPower bikes are just fine.
The other argument is that eBike technology is still rapidly evolving. Motors are getting smaller, lighter, and more powerful. Batteries are getting more capacity and cheaper. The space needed to hold 400 watt hours now holds 700 watt hours, and for not much more money. I can see where people would not want to plunk down a large sum to get a good bike when in just a couple/few years way better bikes will probably be available, and for less money.
AHicks
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My thought exactly:
"I can see where people would not want to plunk down a large sum to get a good bike when in just a couple/few years way better bikes will probably be available, and for less money."
Paying a lot of money for a high end bike that's going to be outdated in 2 years makes little sense, to me anyway.
"I can see where people would not want to plunk down a large sum to get a good bike when in just a couple/few years way better bikes will probably be available, and for less money."
Paying a lot of money for a high end bike that's going to be outdated in 2 years makes little sense, to me anyway.
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