"True 750w" motor upgrade on RadCity 5

Slorider

Member
Region
USA
Since the warranty on my RadCity 5 is going to run out in a few months so I figured it's time for upgrades. The first part came in sooner than I expected because the website said back ordered. I was expecting a two month wait.

It's the "true 750 watt" Befang motor. I've seen a few videos showing how to install it on the RadRover 6 but not for the RadCity 5. I know I have to take it out of the casing but has anyone here upgraded the motor on their RadCity 5? The hub on the City looks a little different because it's not a fat bike so I hope there are no issues with the larger motor fitting.

Will there be any difference in power or noise with everything else stock?


Motor2.jpg
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
I would do some checking before you take anything apart. The RadRover is a fattie, which I'm pretty sure uses a wider motor than what you'll need for the City.
 

Slorider

Member
Region
USA
I would do some checking before you take anything apart. The RadRover is a fattie, which I'm pretty sure uses a wider motor than what you'll need for the City.
Yeah that’s why I am posting here but it doesn’t seem like anyone has done upgrades done upgrades on the RadCity 5 RadRover 6 yet. There are two companies that sell from my understanding the same upgraded controller but it’s not compatible with the newer models and there’s not a newer version out.

The part where the spokes attach is wider but on the city it’s pushed out more on the left side. I don’t have any way to measure and see if it’s pushed out enough to be the same width because I don’t own a RadRover. Even when replacing the motor on a RadRover most people don’t keep the outer shell because it’s easier to replace the inside motor part that way you don’t have to redo the spokes. It is possible that the inside part of the hub won’t fit the larger motor because rad never intended for a larger motor to go inside it. I’m not sure how I would thought out other than asking here if anyone has done it or just trying it.

I’m a bit surprised that after almost a year no one has came out with upgrades for either the new City or Rover. I know many people still have their bikes under warranty but I’ve seen posts from people who just bought their Rad and wanting to upgrade the controller so I don’t think it’s that. Maybe the chip shortage has made it not feasible
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Have you discussed this with the seller, the person you bought the motor from? You need a motor that's about 135mm wide. The fatties run from 170 to 190 or so.

I'm betting the 135's are available, and will install the way you want to. You just need to confirm the motor connector is what you need, and that 135mm width....

All bets are off on the controller mod for the time being. I'm absolutely sure it could be done by the right guys, but I'm just as sure it's not going to be a straight drop in until somebody comes up with a new "kit". We went 3-4 years before the (Bolton) drop in kits were available for the earlier models when they came out...

As far as performance, the Bolton kit for the Rad bikes is rated at 35 amps. I have one of those 35a controllers and it's able to supply 1300 watts, or nearly twice what a 750w motor is rated for, or nearly 3 times what a 500w motor is rated for. So there is a VERY clear difference in performance. The downside is it's very easy to abuse this extra power with too much use. a 500w motor fed 1300w is going to heat up pretty quickly, while providing some pretty "sporty" performance. There are few, if any safeguards in place to prevent burn downs. Point is, you need to ride and use this power with a little (LOT of) common sense.

I have a '17 RAD City I converted to a 1000w MAC 12t geared hub powered by a 35a KT controller that was done just prior to Bolton bringing out his kits. It's provided rock solid performance since, still using the stock RAD battery that came on the bike. Very difficult to tell from a production bike....

That in mind, I have 3 KT-22a waterproof (WP) controllers w/displays installed on 500w bikes (2 Espin Flows, and an Espin Sport). Wide open throttle on these provides about 980 watts - PLENTY for some pretty sporty 500w motor performance. These have been running flawlessly about 2 years now. Provide great battery life, and plenty of zip for crossing a busy street for instance. I would NOT recommend them for an area with a lot of big hills unless you are a smaller rider. -Al
 
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Slorider

Member
Region
USA
Have you discussed this with the seller, the person you bought the motor from? You need a motor that's about 135mm wide. The fatties run from 170 to 190 or so.

I'm betting the 135's are available, and will install the way you want to. You just need to confirm the motor connector is what you need, and that 135mm width....

All bets are off on the controller mod for the time being. I'm absolutely sure it could be done by the right guys, but I'm just as sure it's not going to be a straight drop in until somebody comes up with a new "kit". We went 3-4 years before the (Bolton) drop in kits were available for the earlier models when they came out...

As far as performance, the Bolton kit for the Rad bikes is rated at 35 amps. I have one of those 35a controllers and it's able to supply 1300 watts, or nearly twice what a 750w motor is rated for, or nearly 3 times what a 500w motor is rated for. So there is a VERY clear difference in performance. The downside is it's very easy to abuse this extra power with too much use. a 500w motor fed 1300w is going to heat up pretty quickly, while providing some pretty "sporty" performance. There are few, if any safeguards in place to prevent burn downs. Point is, you need to ride and use this power with a little (LOT of) common sense.

I have a '17 RAD City I converted to a 1000w MAC 12t geared hub powered by a 35a KT controller that was done just prior to Bolton bringing out his kits. It's provided rock solid performance since, still using the stock RAD battery that came on the bike. Very difficult to tell from a production bike....

That in mind, I have 3 KT-22a waterproof (WP) controllers w/displays installed on 500w bikes (2 Espin Flows, and an Espin Sport). Wide open throttle on these provides about 980 watts - PLENTY for some pretty sporty 500w motor performance. These have been running flawlessly about 2 years now. Provide great battery life, and plenty of zip for crossing a busy street for instance. I would NOT recommend them for an area with a lot of big hills unless you are a smaller rider. -Al
I haven’t talk to the seller because I bought it online from Electro bike world. I probably could call or email them but it was the only motor they had listed on their website for Rad bikes. If it doesn’t fit I’ll probably just keep my City stock because it doesn’t seem like there are any upgrade options for it. Maybe I’ll spend my upgrade energy on building an e-bike
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
I haven’t talk to the seller because I bought it online from Electro bike world. I probably could call or email them but it was the only motor they had listed on their website for Rad bikes. If it doesn’t fit I’ll probably just keep my City stock because it doesn’t seem like there are any upgrade options for it. Maybe I’ll spend my upgrade energy on building an e-bike
Well, if considering getting your feet wet with a build, one of these KT-22a conversions might be worth looking in to for your 'City? They're pretty popular installs for those that have purchased bikes with terrible controllers.

How handy are you?
 

Slorider

Member
Region
USA
Well, if considering getting your feet wet with a build, one of these KT-22a conversions might be worth looking in to for your 'City? They're pretty popular installs for those that have purchased bikes with terrible controllers.

How handy are you?
I can do most things mechanical or electrical. I’m not quite up to soldering circuit boards but I’m sure I could learn.

Are you talking about the KT-22a for my RadCity 5 or building a bike? I wouldn’t say the RadCity has a terrible controller because it’s better than some. I have a Lectric XP Lite that the controller doesn’t change the power level with different pedal assist levels. The only thing pedal assist levels do is change the speed pedal assist cuts off. There is only one power level for that controller. I guess it’s acceptable for a commuter bike but not if you want one that’s fun to ride.

If I get a new e-bike or controller I will definitely not get one like that because it seems to burn through the battery faster since it’s always running full power and you can’t really get much exercise.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
I can do most things mechanical or electrical. I’m not quite up to soldering circuit boards but I’m sure I could learn.

Are you talking about the KT-22a for my RadCity 5 or building a bike? I wouldn’t say the RadCity has a terrible controller because it’s better than some. I have a Lectric XP Lite that the controller doesn’t change the power level with different pedal assist levels. The only thing pedal assist levels do is change the speed pedal assist cuts off. There is only one power level for that controller. I guess it’s acceptable for a commuter bike but not if you want one that’s fun to ride.

If I get a new e-bike or controller I will definitely not get one like that because it seems to burn through the battery faster since it’s always running full power and you can’t really get much exercise.
I was thinking KT-22a for the 'City, but if you're happy with that controller, why mess with it? That Lectric sounds like a much more worthwhile project. When you get that bike done and sorted out, THEN you can see if the RAD is worth changing. I've been riding the KT conversions since 2016, consider myself totally spoiled. Any more I just plan on converting any hub drive to KT.

Just briefly, one of the biggest KT advantages is that you can switch it over to power assist. No more speed based PAS levels. You can set an amount of assist you want in PAS 1 so the bike is easily managed at speeds under 8-10 mph. Even 6 mph. Then, as you need more assist (IF you need more assist), you switch to a higher PAS level.

The difficult part of these KT conversions isn't going to require board level soldering ever. It's more about trying to plug a male plug into another male plug. There's no more than 3 wires involved as a rule, so the easiest way is to just splice the right connector on to one side or the other. Hardest part here is figuring out/confirming which one of the 3 is positive, negative, and signal wires on both sides. That's necessary because all of the colors on both sides can be close, but there is NO universal color guide, so confirming what you have is a good plan.

The motor connectors, with 9 wires internally are the most difficult. Hopefully yours is using a standard Bafang connector and that won't be3 any trouble at all.

I am NOT a fan of Electro bike world. They misguide as many people as they help in my opinion.

You can source KT-22a controllers from Amazon. As mentioned, you want to match that motor connection if at all possible. I prefer the controllers with the waterproof connectors (WP). They make for a MUCH tidier install than the rat's nest you end up with controllers where all the connections are made near the controller. That's something Electro Bike World won't tell you as all they stock are the rat's nest type.

Here's an example of the rat's nest type

Another:

And the preferred WP controller using waterproof connectors:

Last, a link to a site that shows a few of the available options when talking KT. There's nothing "standard" to this!
 
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Slorider

Member
Region
USA
I was thinking KT-22a for the 'City, but if you're happy with that controller, why mess with it? That Lectric sounds like a much more worthwhile project. When you get that bike done and sorted out, THEN you can see if the RAD is worth changing. I've been riding the KT conversions since 2016, consider myself totally spoiled. Any more I just plan on converting any hub drive to KT.

Just briefly, one of the biggest KT advantages is that you can switch it over to power assist. No more speed based PAS levels. You can set an amount of assist you want in PAS 1 so the bike is easily managed at speeds under 8-10 mph. Even 6 mph. Then, as you need more assist (IF you need more assist), you switch to a higher PAS level.

The difficult part of these KT conversions isn't going to require board level soldering ever. It's more about trying to plug a male plug into another male plug. There's no more than 3 wires involved as a rule, so the easiest way is to just splice the right connector on to one side or the other. Hardest part here is figuring out/confirming which one of the 3 is positive, negative, and signal wires on both sides. That's necessary because all of the colors on both sides can be close, but there is NO universal color guide, so confirming what you have is a good plan.

The motor connectors, with 9 wires internally are the most difficult. Hopefully yours is using a standard Bafang connector and that won't be3 any trouble at all.

I am NOT a fan of Electro bike world. They misguide as many people as they help in my opinion.

You can source KT-22a controllers from Amazon. As mentioned, you want to match that motor connection if at all possible. I prefer the controllers with the waterproof connectors (WP). They make for a MUCH tidier install than the rat's nest you end up with controllers where all the connections are made near the controller. That's something Electro Bike World won't tell you as all they stock are the rat's nest type.

Here's an example of the rat's nest type

Another:

And the preferred WP controller using waterproof connectors:

Last, a link to a site that shows a few of the available options when talking KT. There's nothing "standard" to this!
Well your comment "I was thinking KT-22a for the 'City, but if you're happy with that controller, why mess with it? That Lectric sounds like a much more worthwhile project." made sense to me. I was just messing with the Rad because the warranty was about to expire and I could. The Lectric could actually use improvement. As to the warranty I'll be replacing the controller, display and brake levers. The only electrical components left will be the motor, battery and lighting but I don't expect to have issues with them. I found a controller with waterproof connectors so it should be easier than the rats nest one. From a post where someone did the same with their Lectric XP (not Lite) a while back they said everything except the brake levers just plugged in. For some reason Lectric uses a different connector on the brake lever but it wasn't very expensive to get new ones. The most money was for the controller and display. I think this will be a good project to give me something to do.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Square wave vs. sine wave, conventional thought has the square wave sometimes noisey (ringing or faint whine) at low speeds, and maybe a little more when accelerating hard. Sine wave are thought to be silent. Other than that they both work equally well. I REALLY noticed the square wave noise on the big 1000-1500w direct drives! My experience on the geared hub motors though, square wave vs. sine wave, has been that you aren't going to notice the difference in noise. I can hear it, but barely. Certainly nothing objectionable as compared to the big direct drives. Sine wave preferred but not too big a concern IMHO.

Betting the Lectric project will spoil you completely as it has myself and many others, and will give you the confidence to proceed with other projects.

Replacing the brake levers with levers known to be compatible is an EXCELLENT plan. You might also consider replacing the PAS sensor for the same reason.... -Al

BTW, my '17 RAD City used the battery over again. The rest of the electrical was all replaced when it was 6 weeks old.....
 
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Slorider

Member
Region
USA
Square wave vs. sine wave, conventional thought has the square wave sometimes noisey (ringing or faint whine) at low speeds, and maybe a little more when accelerating hard. Sine wave are thought to be silent. Other than that they both work equally well. I REALLY noticed the square wave noise on the big 1000-1500w direct drives! My experience on the geared hub motors though, square wave vs. sine wave, has been that you aren't going to notice the difference in noise. I can hear it, but barely. Certainly nothing objectionable as compared to the big direct drives. Sine wave preferred but not too big a concern IMHO.

Betting the Lectric project will spoil you completely as it has myself and many others, and will give you the confidence to proceed with other projects.

Replacing the brake levers with levers known to be compatible is an EXCELLENT plan. You might also consider replacing the PAS sensor for the same reason.... -Al

BTW, my '17 RAD City used the battery over again. The rest of the electrical was all replaced when it was 6 weeks old.....
I’m going to be happy about getting even steady power and not being jerked around by the on off pedal assist. The manual says don’t pedal in turns and I can see why because it’s just too much on and off power. I can’t imagine switching the motor on at 15-16 A then switching off back and forth is very efficient when it comes to battery.

The article I read about the guy doing this on his Lectric XP said he had no issues with the stock pedal assist sensor but that doesn’t mean they haven’t changed things on my Lite. Doesn’t that require removing the bottom bracket or something like that?
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
I’m going to be happy about getting even steady power and not being jerked around by the on off pedal assist. The manual says don’t pedal in turns and I can see why because it’s just too much on and off power. I can’t imagine switching the motor on at 15-16 A then switching off back and forth is very efficient when it comes to battery.

The article I read about the guy doing this on his Lectric XP said he had no issues with the stock pedal assist sensor but that doesn’t mean they haven’t changed things on my Lite. Doesn’t that require removing the bottom bracket or something like that?
Not always. The KT PAS sensor just sort of pushes on, is held in place by friction. You'll need a tool to pull the crank arm. Worst case, pulling it down to the point you can install a sensor on the LH side not that big a deal.