Reference

Rad Power Bikes RadRunner (2025) and RadRunner Max: parts and specs

Replacement parts and specs for the 2025 RadRunner and RadRunner Max: 20 inch tires and 20 x 4 tubes, Gemma hydraulic brakes with 180 mm rotors, single speed or 8-speed drivetrain, battery and charger, with Rad's links and prices.

Last edited Nov 9, 2026 by Pedalwise team Edit History Add a subpage

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This page lists the common replacement parts for the 2025 Rad Power Bikes RadRunner and RadRunner Max utility bikes. The Max has wider tires, gears and different brakes, so each line names the bike it applies to. Specs are for the stock bikes as sold; check your own bike before you buy. Full details are on the RadRunner product page and the RadRunner Max product page. For the RadRunner 1, 2, Plus and 3 Plus, see their own parts pages under Common repairs.

Photo needed: The 2025 RadRunner and RadRunner Max side by side, showing the tire width and the Max's derailleur.. Add one

Electrical parts on this list must match this exact model, and they are fitted at the external plugs or by a pro. Never open the battery, controller, motor or display. For battery and charger trouble, start with battery won't charge and e-bike battery care.

Parts list

Tire: RadRunner uses a custom Rad 20" x 3.3" tire. Rad's RadWagon 5 Tire 20" x 3.3" fits the 2025 RadRunner and RadRunner Plus, $65, out of stock, read Nov 9, 2026. RadRunner Max uses a custom Rad 20" x 3.5" tire. Rad's spare parts store had no Max tire on Nov 9, 2026, so ask Rad support.
Inner tube: Rad's 20" x 4" inner tube fits the 2025 RadRunner, RadRunner Plus and RadRunner Max. Schrader valve, 5 to 30 PSI, $22, shown as shipping within 2 business days, read Nov 9, 2026.
Disc brake pads: Gemma G3 semi-metallic pads as stock on both. Rad's Gemma G2 semi-metallic pads fit the 2025 RadRunner, Plus and Max, $30, out of stock, read Nov 9, 2026. Pads differ between builds (Gemma G2 or G3), so match the pads on your bike or confirm with Rad support before you order.
Brake rotor: 180 mm x 1.8 mm, 6-bolt, on both. Rad's Gemma GR-180 rotor (180 mm x 2.3 mm) fits the 2025 RadRunner Max, $30, out of stock, read Nov 9, 2026. Match the thickness to what is on your bike.
Disc brake caliper: RadRunner has Gemma GA-950E hydraulic brakes. RadRunner Max has Gemma GA-1000B hydraulic brakes.
Freewheel: RadRunner is single speed with a 16 tooth cog. RadRunner Max has 8 speeds, 11 to 34 tooth, with a Shimano trigger shifter and 8-speed rear derailleur.
Hub motor: rear hub, 750W rated on both. The Max is rated 90 Nm.
E-bike display: Rad color display on both. The Max display has a USB-C port.
Throttle: half twist grip on both.
E-bike charger: 48V, 2 A on both. Rad's Rad Battery Charger (MY2025) fits all Rad bikes except the 2016 to 2017 RadMini 1 and the RadKick, $65, out of stock, read Nov 9, 2026.
E-bike battery: RadRunner has a 13 Ah, 624 Wh Safe Shield Advanced external battery. RadRunner Max has a 14 Ah, 672 Wh Safe Shield semi-integrated battery. Ask Rad support for the exact replacement for your bike.
E-bike lights: auto headlight on both. The Max adds a rear light with radar and turn signals. For the 2025 RadRunner, Rad's RadRunner headlight, $45, and RadRunner taillight, $27.50, both fit, shown as shipping within 2 business days, read Nov 9, 2026.
Grips: lock-on ergonomic comfort grips on both.
Pedals: forged aluminum platform, 9/16" x 20 TPI threading on both.

Tools for common jobs

Hex keys: brake caliper and lever bolts, rack and seat checks.
Tire levers: changing a 20 inch tire or tube.
Floor pump with gauge: pumping to the pressure on your tire sidewall after a tube change.
Axle nut wrench: removing the rear hub motor wheel to fix a flat.
Torque wrench: tightening axle nuts and brake bolts to your manual's values.
Brake pad spreader: resetting the hydraulic pistons before fitting new pads.
Brake bleed kit: bleeding the Gemma hydraulic brakes. Confirm the right fluid with Rad support first.
Pedal wrench: swapping the 9/16 inch pedals.
Chain checker: checking chain wear on either bike.
Chain lube: regular chain care.

Where to buy

Rad's spare parts store: tires, tubes and brakes. Much was out of stock on Nov 9, 2026. For a controller, motor or display, ask Rad support.
Independent sellers: our parts suppliers page. A local shop can order and fit parts: find a shop.

Common repairs

Rad Power Bikes troubleshooting and RadRunner error codes
Older RadRunners: RadRunner 1 and 2 parts, RadRunner Plus parts and RadRunner 3 Plus parts
Fix a flat on a rear hub motor wheel and set tire pressure
Replace disc brake pads and bleed hydraulic disc brakes

Sources

Stuck after these checks? Find a shop near you.

Need a pro?

If these steps didn't fix it, find a shop near you in our partner network. For battery or wiring trouble, look for shops marked Battery and electrical.

Talk

Questions, things that worked for you, or something that looks wrong on this page.

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