Trek District+ 4 Coaster Belt Lowstep – Bosch Smart System E-Bike with Gates Belt Drive

The Trek District+ 4 Coaster Belt Lowstep is a premium urban e-bike built around the Bosch Smart System — Bosch's current-generation motor and battery platform that integrates the motor, battery, display, and app connectivity into a single unified system. The motor is the Bosch Active Line Plus, a compact, quiet mid-drive unit well-suited to urban riding and moderate gradients. The battery is semi-integrated into the downtube and available in three capacities: 545Wh, 725Wh, and 800Wh — select the capacity that matches your typical daily range requirement. The lowstep frame provides a low standover height for easy mounting and dismounting, making it accessible for a wide range of riders regardless of flexibility or mobility.

The defining features of the Coaster Belt variant are the Gates CDX carbon belt drive and coaster-actuated hydraulic disc brakes. The Gates belt drive replaces the traditional chain with a carbon fibre reinforced belt that requires no lubrication, produces no grease, and lasts significantly longer than a chain in urban conditions — ideal for commuters who want a genuinely low-maintenance drivetrain. The coaster brake integrates the rear brake into the rear hub, activated by back-pedalling, eliminating the rear brake lever and cable from the cockpit for a clean, minimal setup. Hydraulic disc brakes provide reliable stopping power in all weather. Bosch Smart System connectivity allows ride data, navigation, and motor settings to be managed via the eBike Flow app. For the mudguard-equipped version, see the Trek District+ 4 Guard Lowstep. For a higher-spec model with automatic Enviolo shifting, see the Trek District+ 5 Lowstep. Browse our full e-bike collection and hybrid bikes range.

What It's Good For

• Urban commuting and leisure riding — Bosch Active Line Plus mid-drive motor
• Low-maintenance drivetrain — Gates CDX carbon belt drive, no lubrication required
• Easy mounting and dismounting — lowstep frame with low standover height
• Clean cockpit — coaster rear brake eliminates rear brake lever and cable
• Reliable all-weather braking — hydraulic disc brakes
• Bosch Smart System — eBike Flow app connectivity for ride data and motor settings
• Three battery options: 545Wh, 725Wh, and 800Wh

What It's NOT Good For

• Off-road or trail riding — urban geometry and tyres, not suited to rough terrain
• Riders who prefer a traditional chain drivetrain — belt drive requires a compatible frame and cannot be retrofitted
• High-cadence or performance-focused riding — the Active Line Plus motor is optimised for comfort and efficiency, not maximum power output

Frequently Asked Questions

Which battery size should I choose?
The 545Wh battery suits most urban commutes of up to 20–30 miles per charge in Eco or Tour mode. The 725Wh and 800Wh options extend range for longer commutes, hilly terrain, or riders who prefer to use higher assist levels. Bosch's range assistant tool (available via the eBike Flow app or Bosch website) can estimate range based on your route, weight, and assist preference.

What is a coaster brake and how does it work?
A coaster brake is a rear brake integrated into the rear hub, activated by back-pedalling rather than a hand lever. It's a traditional urban cycling feature that simplifies the cockpit by removing the rear brake lever and cable. The front hydraulic disc brake remains lever-operated. Coaster brakes work well for relaxed urban riding but are less suited to steep descents or situations requiring precise brake modulation — for those, the District+ 4 Guard Lowstep with standard hydraulic disc brakes front and rear may be preferable.

Does the Gates belt drive require any maintenance?
The Gates CDX belt drive requires minimal maintenance compared to a chain. It does not need lubrication, does not produce grease or oil, and is resistant to corrosion. Periodic inspection for wear and correct tension is recommended — Gates recommends checking tension every 500 miles or so. The belt will eventually wear and require replacement, but typically lasts significantly longer than a chain in urban conditions.

What is the Bosch Smart System and eBike Flow app?
The Bosch Smart System is Bosch's current e-bike platform, integrating the motor, battery, display, and connectivity into a unified system. The eBike Flow app (iOS and Android) connects to the bike via Bluetooth and allows you to adjust assist modes, view ride statistics, plan routes with range estimation, and update firmware. The system also supports Bosch's Kiox 300 and Purion 200 displays for on-bike information without using a phone.