Rad Mini "locks up" when I stop pedaling

hughj555

New Member
Region
USA
My 2019 Rad mini step thru with 1600 miles "locks up" when i stop pedaling or reduce PAS to zero or turn off controller while pedaling. Everything returns to normal when the bike comes to a complete stop. It feels like the brakes are applied but the brakes are not what is stopping the bike. Its like the motor (or something in drive train) is fine as long as motor is running but grabs when motor torque is removed. When the bike comes to a stop it is like nothing ever happened, until I start going again and stop pedaling. I can ride bike without the power on and it is fine, but when I turn power on it stops like some sort of motor braking is applied. The wheel brakes are not what is stopping the bike. I have searched the internet and forums and can not find anything similar to my problem. Any help would be truly appreciated.
 

legsofbeer

Active Member
When you say "locks up", do you mean the rear wheel refuses to turn and you skid to a stop, or that a lot of drag is coming from the rear wheel? Do you get any error code from the display?

Regardless, just as a sanity check I would check every connection in the wiring harness, especially the one up front where a pair of aluminum bits twist together, had that jiggle loose on me (I'm assume you have the same overall wiring harness as me on a different model radpower bike). The full guide to checking a mini step-thru's wiring harness: https://radpowerbikes.zendesk.com/h...Mini-Step-Thru-Error-30-Troubleshooting-Guide
 
Last edited:

hughj555

New Member
Region
USA
When you say "locks up", do you mean the rear wheel refuses to turn and you skid to a stop, or that a lot of drag is coming from the rear wheel? Do you get any error code from the display?

Regardless, just as a sanity check I would check every connection in the wiring harness, especially the one up front where a pair of aluminum bits twist together, had that jiggle loose on me (I'm assume you have the same overall wiring harness as me on a different model radpower bike). The full guide to checking a mini step-thru's wiring harness: https://radpowerbikes.zendesk.com/h...Mini-Step-Thru-Error-30-Troubleshooting-Guide
Thanks for the help. By lockup I mean the rear wheel has a LOT of drag but does not skid unless in loose sand. It comes to a stop pretty quick. What ever is causing the drag releases when the bike stops moving. It is like nothing is wrong. It will take off and go like normal until i stop pedaling. With the rear wheel off the ground I can spin the wheel but it is a little tight and maybe a little noisy, and comes to a stop sooner than my wifes bike when i do the same. The brake is not dragging. There are no codes at all. I will check the wiring again but haven't found any problems so far.
 

hughj555

New Member
Region
USA
Is the freewheel working?
Thanks, I'm not sure how to do a checkout of the freewheel. The wheel will rotate forward and backward and I can pedal forward and backward. if moving and I stop pedaling the bike stops like the brakes are applied hard. But the brakes are not causing the problem. It feels like the motor is trying to lock the hub? when the bikes stops I can start pedaling again and everything is normal until i stop pedaling. I can go thru all the gears and PAS levels. If I turn the PAS off it does the same thing as when I stop pedaling. It comes to a stop and there is nothing i can do until the bike comes to a complete stop. With power off i can still ride the bike with no problems. If I turn power on while riding bike it comes to a stop?! I think it is something in the motor/hub but I have no experience with the internal workings of it. I guess it's time to learn. I'm looking for any ideas to start my learning process :)
 

legsofbeer

Active Member
Thanks for the help. By lockup I mean the rear wheel has a LOT of drag but does not skid unless in loose sand. It comes to a stop pretty quick. What ever is causing the drag releases when the bike stops moving. It is like nothing is wrong. It will take off and go like normal until i stop pedaling. With the rear wheel off the ground I can spin the wheel but it is a little tight and maybe a little noisy, and comes to a stop sooner than my wifes bike when i do the same. The brake is not dragging. There are no codes at all. I will check the wiring again but haven't found any problems so far.
As mentioned above, sounds like your freewheel is malfunctioning. Maybe take it apart and lube it? This describes how to do that, though obviously your problem is the opposite of a "skipping" freewheel. Turn off or remove your battery before doing this: https://www.wikihow.com/Fix-a-Skipping-Freehub-on-a-Bicycle

ETA: this thread implies that a "special tool" is needed from rad to remove a 2018 radmini freewheel (yours is 2019). Maybe @AHicks can comment on this? https://electricbikereview.com/foru...cassette-change-on-my-radmini-under-50.14834/
 
Last edited:

hughj555

New Member
Region
USA
As mentioned above, sounds like your freewheel is malfunctioning. Maybe take it apart and lube it? This describes how to do that, though obviously your problem is the opposite of a "skipping" freewheel. Turn off or remove your battery before doing this: https://www.wikihow.com/Fix-a-Skipping-Freehub-on-a-Bicycle

ETA: this thread implies that a "special tool" is needed from rad to remove a 2018 radmini freewheel (yours is 2019). Maybe @AHicks can comment on this? https://electricbikereview.com/foru...cassette-change-on-my-radmini-under-50.14834/
Thanks. Im travelling right now but will give it a shot soon.
 

hughj555

New Member
Region
USA
Update. Took bike to shop and they diagnosed with Radpower that it was the motor. Couldn't tell me what the failure mode was but were confident it was the motor. I will do an autopsy and see what failed and what caused it.
 

legsofbeer

Active Member
Update. Took bike to shop and they diagnosed with Radpower that it was the motor. Couldn't tell me what the failure mode was but were confident it was the motor. I will do an autopsy and see what failed and what caused it.
What are they charging you for a new motor (I assume you're out of warranty). Or are you going for an aftermarket replacement?
 

hughj555

New Member
Region
USA
388 total w/free shipping from Radpower. comes with new wheel/tire. I am travelling so they are going to ship it to a relative we will see in a week or so. i will replace it myself. I wish I was home so I could take it apart and replace the defective component. Thanks again for everyone's help.
 

legsofbeer

Active Member
Do you know a good aftermarket parts shop for the Radpower bikes?
No one-stop shopping, as far as I can tell. You have to look around. Bolton sells controller and hydraulic brake upgrades, and used to sell motor upgrades (always sold out whenever I check). Tires and tubes you can get anywhere, though I think radpower's tire&tube prices are pretty fair. Looking at the bolton 750w gear hub motor, if it were available that would be $250 for motor + $50 for freewheel removal tool + $50 for a new freewheel, so $380 for a convenient dropin wheel replacement seems ok.