If your Rad Power Bikes e-bike has stopped working, the method is the same as on any e-bike: find the failed part before you buy one. What is different for Rad owners is sourcing. When we last went through Rad's own spare-parts store, on October 19, 2026, it listed no controllers, displays, throttles, sensors, wiring harnesses or motors. This page sorts common Rad faults by symptom, gives the check Rad's Help Center puts first, and shows where an aftermarket part can, and cannot, stand in for the original.
Where Rad Power Bikes stands, in dated facts
- Rad Power Bikes, Inc. filed for Chapter 11 bankruptcy on December 15, 2025.
- Life Electric Vehicles acquired certain of its assets, and the brand now trades under Rad Life Mobility. Rad's warranty page dates the new ownership to February 27, 2026; Life EV's press release announcing the completed acquisition is dated March 5, 2026. We report both dates as published.
- Rad's warranty page (last updated May 14, 2026) states that the new owner has no obligation to provide warranty or other service for products purchased before December 15, 2025. We do not interpret what that means for your bike; read the page against your own purchase date.
- On October 19, 2026, Rad's spare-parts collection had 66 listings: batteries and chargers, lights, brake parts, tires and tubes, seats, grips, pedals and drivetrain parts, keys and one front wheel. None of them was a controller, display, throttle, pedal-assist sensor, wiring harness or motor.
Stock changes. Check Rad's spare-parts page and ask Rad's support before you buy an electrical part anywhere else; we found no statement either way on whether those parts can be supplied on request.
Find your symptom
The middle column is what Rad's Help Center puts first for that fault, in our words. The right-hand column is the RideRow guide that walks through it.
| What you see | Rad's first step | Read next |
|---|---|---|
| Nothing powers on | Battery first. On external-battery bikes the key has to be in the ON position. A semi-integrated battery can be in ship mode (bright orange sticker); holding its button for at least three seconds wakes it. Then check the connectors one at a time. | Rad won't turn on: connector-by-connector check |
| Throttle dead, pedal assist works | Rad recommends replacing the throttle and its wiring harness, and suggests borrowing a throttle from another bike as a test. | Rad throttle not working |
| Throttle works only in some positions | Rotate the throttle so the hump the wire comes out of points straight down; Rad links this to the throttle magnet and the brake lever magnet interfering. | Rad throttle not working, step 3 |
| Code 17, 22 or 25 at power-up | Let go of the throttle and both brake levers while the bike starts, then reseat the throttle or brake connector. A 22 that stays after reseating points at the throttle body. | Rad Power error codes |
| Code 6 that keeps coming back | Rad separates an occasional undervoltage code (riding load, a low or cold pack) from a persistent one, which sends you to the battery contacts and mount: look for corrosion and burn marks. | Rad Power error codes |
| Any other code | Write the number down and note whether it is constant or comes and goes. Codes 23 and 24 point at the motor cable and its plug at least as often as at the motor. | E-bike error codes by display |
| Display reads km/h | It is a menu setting called Units. Where it sits depends on whether your color display has its buttons on a remote or built in. | Rad display km/h to mph |
| Motor moves on its own | Stop riding, switch off and take the battery out before you look for the cause. | Motor runs by itself |
| You need a controller, display, throttle, sensor, harness or motor | Not listed in Rad's store on October 19, 2026. Ask Rad's support first. | What Rad still sells in 2026 |
Which Rad are you working on?
Rad's Help Center splits its power-on steps by battery layout, and the split is a quick way to place your bike:
- External battery: RadWagon, RadRunner, RadMission, RadCity 4 and earlier, RadRover 5 and earlier, RadExpand and RadMini.
- Semi-integrated battery: Radster, RadRunner 3 Plus, RadRover 6 Plus and RadCity 5 Plus.
- Integrated battery: RadKick, which Rad covers in its own article.
For parts, the controller layout matters more than the year on the frame. Earlier Rad bikes carry the controller in its own housing, wired to the motor, display and battery through plugs that follow patterns the wider industry also uses. Many bikes built from roughly 2021 onward have the controller integrated into the frame, with a battery bay and harness specific to the model. That second group leaves very little room for third-party parts.
Can an aftermarket controller kit replace yours?
Work through these questions in order. A "no" at any step ends the kit route for that bike.
- Is the controller a separate, housed unit? If it is built into the frame, treat the bike as unsuited to a universal kit.
- Does the bike have the newer 500-lumen headlight system? Area 13 Ebikes, which builds KT-based upgrade kits for Rad bikes, warns that this light can destroy an aftermarket controller. Treat those bikes as incompatible rather than looking for a workaround.
- Where does your model sit in the published testing? Area 13's results for its kit (a KT 35A controller with an LCD8H display) sort the range into three groups. Fits without modification: the 2016 to 2018 RadRover and the 2019 to 2021 RadRover up to Rover 5. Fits with work on mounting or wiring: RadCity, the older RadWagon, Runner, RadExpand 5 in the cadence-sensor version only, Mission, and Runner Two and Runner Plus. Not compatible: Rover 6 and RadWagon 5.
- Is there room? Area 13 lists its kit controller at 7.5 by 3.25 by 1.75 inches, larger than the original on several models, so some installs need a fabricated bracket. Measure the space before ordering.
- Do the controller and display match? They talk over a protocol, and a display from another family will not work with a KT controller even if the plug fits. Buy them as a matched set.
- Do the numbers line up? Battery, controller and motor must share the same voltage, and the controller's current has to stay within what the battery can deliver continuously.
The detail behind each step is in which Rad Power models can use an aftermarket controller kit, and the general process is on our controller replacement page.
Before you order any part
Matching by connector and specification is what makes a part fit; the bike's name is not enough. Have these ready:
- A clear photo of the display face showing its model marking, and a close-up of its connector (pin count and plug gender).
- The controller label, if your bike has a separate controller, with its voltage and current ratings legible.
- The motor cable where it leaves the wheel.
- For a wheel or motor job: your measured dropout width and the wheel and tire size from the sidewall. Fat-tire e-bikes in the 750 to 1000 W class have settled on 170 mm or 190 mm rear dropouts, and the two are not interchangeable.
Our guide to the four photos we need to confirm a part fits shows what each photo should capture, and Find My Part is where to send them. When you compare parts, browse e-bike spare parts by connector and rating, not by bike name.
Rad jobs to leave alone
- Damaged battery connectors. For semi-integrated batteries, Rad says that if the inside of the connector is damaged or dirty you should not try to repair it or clean the contacts. Do not open a battery pack.
- The security menu on color displays. Rad notes that security left at its default passcode uses four zeros, and that a forgotten passcode or lost key cards means a service center visit. Stay out of it while you are chasing another setting.
- Wiring the 500-lumen light to an aftermarket controller. See step 2 above.
- Riding with a brake sensor unplugged. Unplugging one at a time is a test, not a fix; the motor cut-off has to work before the bike goes back on the road.
All Rad Power Bikes guides on RideRow
- Rad Power Bike Won't Turn On: A Connector-by-Connector Check Beyond the Battery
- Rad Power Bikes Throttle Not Working: Test the Throttle and Pedal Assist Separately
- Rad Power Error Codes: The Complete Reference, Updated for 2026
- Rad Power Bikes Display Showing km/h Instead of mph
- Which Rad Power Models Can Use an Aftermarket Controller Kit?
- What Rad Power Still Sells in 2026, and the Electrical Parts You Have to Source Elsewhere
- Rad Power Bikes After the Bankruptcy: Where to Get Replacement Parts Now
Brand-neutral guides that apply to most Rad faults: the power-chain checklist, the brake sensor guide, the 21 to 30 code family and e-bike turns on but won't move.
Sources
Rad Power Bikes Help Center articles on bikes that won't turn on (external and semi-integrated battery), throttle troubleshooting, error codes by bike model and the Advanced and Integrated Color Displays, as cited in each guide above; Rad's Limited Warranty Terms and spare-parts collection, read October 19, 2026; Life EV's press release of March 5, 2026; Area 13 Ebikes' published Rad kit compatibility and dimensions. Rad's pages change, so check the current version via Rad's support page.
RideRow is an independent parts retailer and is not affiliated with, endorsed by, or sponsored by Rad Power Bikes. Rad Power Bikes and model names are trademarks of their respective owners and are used here only to identify the bikes this guide covers. This page is general information for owners who do their own work; RideRow sells parts and publishes how-to guides and does not repair bikes. If you are not confident working on electrical parts, use a qualified e-bike technician.
Last updated: November 2026