Fat tire & moto
Ariel Rider Kepler
$1,699
Price
118 Nm
Torque
1040 Wh
Battery
98.6 lb
Weight
Ariel Rider Kepler vs Rad Power Bikes Radster Trail
Two fat tire & moto e-bikes at $1,699–$1,999, every published spec lined up. Nothing here is estimated: a figure the manufacturer does not publish is shown as “—”.
vs
Fat tire & moto
Rad Power Bikes Radster Trail
$1,999
Price
100 Nm
Torque
720 Wh
Battery
77.5 lb
Weight
Where they differ
- The Kepler carries 320 Wh more battery.
- The Radster Trail is 21.1 lb lighter.
- The Kepler carries 80 lb more total load.
- The Kepler makes 18 Nm more torque.
- The Kepler costs $300 less.
- The Kepler claims 10 more miles of range.
- The Kepler uses a torque + cadence sensor; the Radster Trail uses a torque sensor.
Every spec, side by side
| Kepler | Radster Trail | |
|---|---|---|
| Headline | ||
| Price | $1,699 | $1,999 |
| Category | Fat tire & moto | Fat tire & moto |
| Price per Wh | $1.63 per Wh | $2.78 per Wh |
| Model year | 2026 | 2026 |
| Motor | ||
| Torque | 118 Nm | 100 Nm |
| Motor power | 750 W | 750 W |
| Peak power | 1940 W | — |
| Drive | Rear hub | Rear hub |
| Motor make | Ariel Rider | Rad |
| Sensor | Torque + cadence | Torque |
| Battery & range | ||
| Battery | 1040 Wh | 720 Wh |
| Voltage | 52V | 48V |
| Capacity | 20 Ah | 15 Ah |
| Cells | Samsung 21700 | Samsung 50GB or LG M50LT |
| Removable battery | Yes | Yes |
| Range (claim) | 75 mi | 65 mi |
| Range as stated | Up to 75 miles | 25-65 miles |
| Est. real range | 42 mi | 29 mi |
| Estimate assumes | 25 Wh per mile | 25 Wh per mile |
| Weight & capacity | ||
| Weight | 98.6 lb | 77.5 lb |
| Max load | 400 lb | 320 lb |
| Class & speed | ||
| Ships as | Class 2: throttle, assist to 20 mph | Class 2: throttle, assist to 20 mph |
| Unlocks to | Class 3 | Class 3 |
| Class | Class 2–3 | Class 2–3 |
| Throttle | Yes | Yes |
| Top assisted speed | 28 mph | 28 mph |
| Build | ||
| Gears | 8-speed | 8-speed |
| Drivetrain | Shimano Altus (13-32T) | Shimano |
| Brakes | Hydraulic disc | Hydraulic disc |
| Front rotor | 203 mm | 180 mm |
| Rear rotor | 203 mm | 180 mm |
| Suspension | Hardtail (front only) | Hardtail (front only) |
| Fork travel | — | 80 mm |
| Rear travel | None | None |
| Front suspension | Yes | Yes |
| Suspension seatpost | — | No |
| Tires | 24 x 4.0 | — |
| Display | Large full-colour, Bluetooth, USB-C | Rad colour display |
| Frame | — | Aluminium |
| Sizes | One size | Regular, Large |
| Step-through option | No | No |
| Included | ||
| Lights | Yes | Yes |
| Fenders | — | Yes |
| Rack | — | Yes |
| Kickstand | — | Yes |
| Safety | — | UL 2849* |
| Safety certification | — | UL 2849: most models, confirm this one |
| As the maker states it | "UL Safety Certified" stated without naming the standard | "UL Certified to UL 2849 and UL 2271" on individual product pages, with the lineup-wide claim hedged as "All Rad ebikes are either UL Certified or tested by ACT to comply with UL 2849" |
| Warranty | — | 2 yr |
| Warranty terms | — | Two year limited warranty; battery 300 recharge cycles or 2 years, whichever comes first (brand policy) |
Specs transcribed from arielrider.com on 2026-09-20 and www.radpowerbikes.com on 2026-09-20. Manufacturers revise specs without notice: confirm before buying.