KELLYS Theos RSX40
Universal full suspension e-MTB designed for trail and more demanding terrain. A powerful Panasonic GXM 100Nm motor, 725Wh battery and RockShox suspension ensure performance, comfort and confidence. With mullet wheels, it offers great stability, handling and reliability on every ride.
Expected delivery date 2Q / 2026
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PANASONIC GXM
100 Nm
725 Wh
9 speeds
29", 27,5"
140 mm (front)
Shock absorber ROCK SHOX Super Deluxe DebonAir+ R (210x55 mm)
The ultimate rear shock designed for full suspension mountain bikes, combining excellent responsiveness, stability and control. Thanks to the innovative DebonAir+ system, it provides exceptionally smooth operation and optimal support throughout the entire travel range.
- DebonAir+ Chamber
- Hydraulic Bottom Out (R HBO)
- Durable Construction
- Simple Setup
RockShox Recon Silver RL 29″ Boost 140 mm - reliable fork for trail and e-MTB
The versatile and powerful RockShox Recon Silver RL front fork. With a BOOST 15×110 mm axle and 140 mm travel, it's ready to handle demanding trails, enduro and everyday mountain riding. With Solo Air suspension, easy adjustment to rider weight and Motion Control with adjustable compression and external rebound, you have perfect control over the fork's action. 32mm steel sliders with Fast Black finish.
Electric bikes with a mullet setup (a combination of a 29" front and 27.5" rear wheel) are becoming increasingly popular among enduro and trail riders. This concept brings the benefits of both wheel sizes, improving off-road handling.
- Better off-road handling
- Improved stability
- Better handling
- Lower centre of gravity
- A more natural ride feel
KELLYS Theos RSX40 - a reliable full suspension e-MTB for a real off-road experience
The KELLYS Theos RSX40 e-bike is a balanced combination of performance, comfort and versatility. It is designed for riders who want to enter the world of full suspension e-MTBs and expect stability, confidence and strong motor support even on the most demanding trails. That's why the RSX40 is one of the models that will quickly gain the trust of recreational and sport-minded cyclists alike.
Powerful engine and long range as the basis for a confident ride
At the heart of the bike is a powerful Panasonic GXM mid-motor capable of delivering up to 100 Nm of torque. In practice, this means instant response, smooth traction and excellent support even on steep climbs. The motor is also naturally quiet and has a very smooth onset of assistance.
Power is taken care of by a large-capacity 725 Wh battery that provides a range of around 120 to 150 km, depending on riding style and terrain. This is a great parameter for day trips without constantly monitoring percentages.
RockShox suspension for confidence on any trail
The Theos RSX40 uses a full-suspension design with a RockShox Recon front fork and RockShox Deluxe rear shock. The 140mm of travel provides comfort on roots, rocks and twisty forest trails. The damping is responsive and reliable, so the rider has a constant sense of control - whether he's descending technical sections or just riding on broken gravel.
Mullet fitment - stability and playfulness in one
Kellys uses the popular "mullet" wheel combination on this model: 29" at the front and 27.5" at the rear.
- The 29" front wheel provides great ground clearance and confidence at higher speeds.
- The 27.5" rear wheel gives the bike agility and faster response in twisty passages.
The result? Very balanced handling suitable for a variety of conditions.
Components that won't disappoint
Shimano CUES 1×9 gears provide reliable range for most riding situations, and hydraulic disc brakes provide plenty of stopping power even with the higher weight of the e-bike. The frame construction is modern and solid, designed to transfer power efficiently while damping vibration well. The bike feels sturdy, yet nicely balanced.
Who is the Theos RSX40 ideal for?
- For riders who want a quality full suspension e-MTB without an extremely high investment.
- For those planning trail riding, forest tours and hilly trails.
- For riders looking for a powerful motor, long range and confidence in the off-road.
- For athletes and recreational cyclists who want one versatile bike for everything.
The KELLYS Theos RSX40 is an e-MTB that has a lot to offer. It combines a solid technical base, a powerful Panasonic motor, long battery life and comfortable RockShox suspension. This makes it the ideal partner for demanding trips, trail rides and everyday riding pleasure.
KELLYS BICYCLES s.r.o. now offers an extended warranty of 5 years. This extended warranty covers the frame of the e-bike and its claim when a manufacturing or material defect is proven to be the cause.
E-bike range calculator
Flat
Medium
Hills
The e-bike range is approximately
*Factors affecting total range include technical condition of the e-bike, battery age, ambient temperature, headwind, and riding technique
Panasonic GXM 100 Mg Motor
The Panasonic GXM 100 Mg mid-drive motor is the flagship of the new generation of GXM e-bike drives (“Great eXperience in eMotion”). It delivers up to 100 Nm of torque, features an ultra-light magnesium casing weighing only about 2.6 kg, an open CAN-bus system allowing third-party battery use, and supports OTA (Over-The-Air) updates via a mobile app. Ideal for high-performance e-MTB bikes and demanding terrain.
Battery Kellys Maxxpro 725 Wh
Kellys, in cooperation with German battery manufacturer BMZ, presents a new series of batteries called Maxxpro, which excel in high energy density. Energy density is the amount of energy stored in a given amount of material, measured in Wh/kg. Carbon batteries are up to 20% lighter and offer higher capacity. The batteries weigh approximately 3.5 kg. To achieve low weight and high energy density, Kellys used an all-carbon battery body.
PANASONIC GXM Center Display 501
A highly modern central display designed for e-bikes with Panasonic drives. This display provides a clear overview of all key information – from speed, range, and assistance level to navigation and connection to a smart app via Bluetooth® 5.0. Enables stable and fast connection to smartphones and Panasonic apps, including firmware updates and ride data transfer. Intuitive navigation. The display provides information on speed, range, battery status, assistance mode, and other bike functions. The display is resistant to water, dust, and vibrations, and is readable even in direct sunlight.
GXM Remote 501
A modern control unit located on the handlebars, designed for intuitive control of e-bikes equipped with Panasonic GX series drives. The controller allows quick and safe switching between assistance levels and control of additional functions. Designed to be easily accessible with your thumb, minimizing the need to take your attention off driving. Ergonomic design. Intuitive button layout. High durability. Fast response and precise control. Seamless integration with Panasonic GX and GXM series motors and displays.
Designing and manufacturing e-bikes is not just about putting mechanical components together. It's more than that. The purpose for which an e-bike is created is important, because it has a unique purpose in each person's life. This mission gives every KELLYS e-bike its reason for being. Thanks to modern technology, skilled designers and the best materials, the Kellys brand has some of the highest quality e-bikes.
We are specialists in KELLYS electric bikes. We offer full suspension and fixed mountain bikes, touring bikes, men's and women's electric bikes with an excellent price / performance ratio.
Contact: KELLYS BICYCLES CZECH REPUBLIC s.r.o., Havlickova 426, 753 01, Hranice, Czech republic, e-mail: infocz@kellysbike.com, phone: +420 581 698 810, web: https://kellysbike.com
Parameters
General
| Model year | 2026 |
| Brand | Kellys |
| Frame size | Frame L, Frame S, Frame M |
| Load capacity | 120 kg |
Motor
| Engine manufacturer | Panasonic |
| Engine type | Panasonic GXM |
| Torque | 100 Nm |
| Centre engine | Yes |
Battery
| Battery capacity | 700 - 799 Wh |
| Precise capacity | 725 Wh |
Transmission
| Number of gears | 1x9 |
| Sort by | Shimano Cues SL-U4000-9R, Rapidfire Plus, 9 speeds |
Components
| Saddlebag | KLS Active - diam 30.9 mm / length 350 mm |
| Saddle | Selle Royal SRX Plus |
| Front hub | Shimano TC500-15B |
| Coats | Schwalbe Johnny Watts 60-622 |
| Extender | adjustable SATORI FASTBACK a-head - diam 28.6 mm / bar bore 31.8 mm / length 50 mm |
| Handlebars | KLS Active RiseBar - diam 31.8 mm / rise 18 mm / width 760 mm |
| Racks | KLS Asesino 30 Disc 622x30 (32 holes) |
Brakes
| Front brakes | Shimano MT200, hydraulic, 203 mm |
| Rear brakes | Shimano MT200, hydraulic, 203 mm |
Suspension
| Shocks | ROCK SHOX Deluxe Select, DebonAir+ / R damper (210x55 mm) |
| Front fork | ROCK SHOX Recon Silver RL (29") Boost, 140 mm, Solo Air / Motion Control / Maxle Stealth 15 mm thru axle |
Questions
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