1 Introduction

This OEM guideline serves as an extension and support to the generally applicable standards and regulations in accordance with the current state of the art.

Using the UTgear H2 under the conditions described in this TCD and the associated agreed documents is a prerequisite for Universal Transmissions GmbH (UT GmbH) to confirm that the product is suitable for its intended or customary use or possesses a specific condition or quality.

If individual components of the UTgear H2 are replaced with components from third-party suppliers, or if UTgear H2 components are modified, warranty and product liability claims will be rejected if the modification or the third-party component caused the alleged defect or damage.

In addition to the TCD, the developer, designer, or manufacturer has access to the OEM CAD package and other OEM documents (see Chapter 10 – Related Documentation)

To request these documents or for questions regarding the TCD, please contact your technical representative.

1.1 General Responsibilities

The bicycle manufacturer is responsible for the design, structural integrity, durability, and overall quality of the complete bicycle, including all drivetrain components and all components relevant to rider safety.

The OEM (Original Equipment Manufacturer) must ensure the structural stability of the frame and verify the compatibility of all bicycle components, including those integrated with the UTgear H2 system.

1.2 Safety Warnings

CAUTION!
Indicates a condition that may cause material damage or environmental harm if not avoided.

WARNING!
Indicates a hazardous situation which, if not avoided, may result in minor or moderate injury.

DANGER!
Indicates a hazardous situation which, if not avoided, could result in serious injury or death.

2 Product Description

The UTgear H2 is a compact, low-maintenance, two-speed planetary gearbox designed for urban and trekking bicycle drivetrain systems. It is engineered as a direct-mount auxiliary gearbox for the HG-standard interface used on the Bosch Hubline.

Gear selection is performed via a purely mechanical actuation system , providing defined shift points and eliminating the need for electronic control interfaces. The internal planetary gear-stage architecture enables high transmission efficiency, precise shift engagement, and consistent operational behavior across varying load conditions. All load-bearing elements are designed for high durability, making the system suitable for sustained daily use.

The gearbox supports shift-under-load operation as well as stationary shifting , enabled by the kinematic properties of the planetary mechanism. This ensures reliable function in stop-and go traffic and under typical urban riding loads.

The gearbox is intended for use on bicycles classified under DIN EN 17406 – Category 2.

3 Compatibility

CAUTION!
Using components not listed in this documentation may impair system functionality or cause damage to the UTgear H2.

The UTgear H2 gearbox is tested and approved only in combination with the following components:

• UTgear H2 - Thumb Shifter (UTG-H2-ST-SR-A1)
• Gates Belt Drive components
• Bosch Hubline (BDU30xx)

4 Technical Data

4.1 Ambient & Storage Conditions

4.2 Gearbox Unit

• Weight: 890 g (without sprocket, shifter, cable and assembly parts)
• Material:
  • Housing material: Aluminium (anodized)
  • Gears material: Hardened steel
• Color: Black matte
• Interface: HG-standard (HG freewheel body Bosch Hubline BDU30xx only)
• Torque at bottom bracket: ≤ 250 Nm
• Primary gear ratio: ≥ 1.7
• Gear ratios:
  • Gear 1: 1:1
  • Gear 2: 1:1.4
• Variants:
  • with pre-assembled Gates H2 26T rear sprocket
  • with pre-assembled Gates H2 28T rear sprocket
• Dimension:

For further details see offer drawing.

4.3 Thumb Shifter

• Weight: 121g (w/ cable)
• Material:
  • Shifter body material: Composite Material
  • Mounting clamp material: Aluminium
• Color: Black matte
• Handlebar clamp diameter: 22.2 mm
• Integrated cable length: 2250 mm
• Shift-cable: Ø 1.20 mm
• Dimension:

For further details see offer drawing.

5 Product Versions

The UTgear H2 will be offered in two distinct variants, differing exclusively in the number of teeth of the pre-assembled sprockets and the labyrinth seal.

• 30000167 – UTgear H2 2-speed adapter gearbox for HG freewheel, incl. sprocket 26T (UTG-H2-GB-TS-A1-26T)
• 30000168 – UTgear H2 2-speed adapter gearbox for HG freewheel, incl. sprocket 28T (UTG-H2-GB-TS-A1-28T)

The shifter and cable are not included in the gearbox unit’s scope of delivery and must be ordered separately.

• 30000154 – UTgear H2 2-speed thumb shifter 22,2mm, incl. cable 2250mm (UTG-H2-ST-SR-A1)

5.1 Parts List

5.2 Label

Gearbox

1 Serial Number

2 Product Code

3 QR Code #1 (Service documentation)

4 QR Code #2 (Production Quality Management)

Thumb Shifter

1 Serial Number

2 Product Code

6 Integration

The design of the UTgear H2 gearbox enables straightforward integration into both new and existing bicycle drivetrain configurations. UTgear H2 is a bolt-on, two-speed planetary gearbox for rear hub motors using an HG-standard interface.

6.1 Integration Requirements

The gearbox is currently approved for series use exclusively in combination with the Bosch Hubline (BDU30xx) and Gates Belt Drive components , based on completed testing and validation.

The use of components from other manufacturers is not automatically approved . Approval can only be granted by Universal Transmissions GmbH . Please contact your technical representative for further evaluation.

CAUTION!
To avoid component damage, compliance with the respective component manufacturers’ guidelines is mandatory during integration.

Bosch Hubline

All Bosch specifications and installation guidelines applicable to the Bosch Hubline motor system must be strictly followed .

Gates Belt Drive

For all configurations using Gates Belt Drive systems, the corresponding Gates installation and system requirements must be strictly followed. Especially frame stiffness, belt alignment and belt tension requirements must be strictly followed.

6.2 Frame Design / Torque Support

DANGER!
Insufficient frame stiffness increases the risk of an accident due to the belt jumping or derailing caused by severe frame torsion.

CAUTION!
Insufficient frame stiffness leads to belt misalignment, which cause noise and increased wear.

The gearbox is not intended to absorb additional structural loads from the bicycle frame.

During frame development, adequate frame clearance (2 mm) must be ensured to prevent any potential collision between the gearbox assembly and surrounding frame structures. Consider dynamic movement under load, tolerance stack-ups, and manufacturing variation.

During frame design, shift-cable routing must also be considered to ensure smooth operation, adequate clearance, and compatibility with the gearbox actuation system. (See Chapter 6.5 - Cable Routing Requirements)

A dedicated torque support is required for proper operation of the UTgear H2. This torque support must follow the UT-approved concepts to ensure that all reaction forces are safely controlled and that no unintended loads are introduced into the gearbox housing.

Two torque support concepts are currently approved:

1. Standard derailleur hanger interface:

The torque support bolt can be mounted directly to a standard derailleur hanger with M10x1 thread. This offers a straightforward, widely compatible solution that fulfils all functional requirements when installed in accordance with UTgear H2 specifications. The defined distance between the axle and the torque‑support mount is 30 mm. See picture for reference.

2.UT‑approved non-turnable UDH variant:

Only the UT‑approved UDH (UTG-H2-DH-TS-A1) design may be used. It is engineered to not rotate or fold away under load, unlike a standard UDH, which is designed to deflect during impacts. This non‑turnable behavior provides a stable and secure torque reaction path for the gearbox. The stop tab or hook (see red marking) ensures that the unit cannot rotate. Either one of these two features is sufficient.

Any deviation from the UT-approved torque support concept lies solely within the OEM’s responsibility. Alternative torque support solutions must be fully evaluated, validated, and released by the OEM to guarantee proper load management and safe operation of the drivetrain system.

6.3 Beltlines

DANGER!
Belt misalignment increases the risk of an accident due to the belt jumping or derailing caused by severe frame torsion.

CAUTION!
Noise generation and increased wear caused by belt misalignment.

The following table shows the resulting beltlines for all hubs and hub motors, approved by UT GmbH.

If multiple beltline values are listed, the final beltline depends on the position of the UTgear HG ‑ Spacer (UTG ‑ H2 ‑ AA ‑ TS ‑ UT0025). Refer to the image below for correct spacer placement.

A) Transmission Installation – 53.1 mm Beltline

1. Slide the gearbox unit onto the HG freehub body.

2. Install the 1.5 mm spacer onto the HG freehub body.

B) Transmission Installation – 54.6 mm Beltline

1. Slide the 1.5 mm spacer onto the HG freehub body.

2. Install the gearbox unit onto the HG freehub body.

6.4 Thumb Shifter

The thumb shifter is specifically designed for shifting with the UTgear H2. The objective of its development was to provide clear, unambiguous shift feedback. With a defined lever travel, every shift operation is initiated precisely. Being maintenance‑free and IP55‑rated, the thumb shifter offers a durable and reliable actuation interface.

1 Lever - Gear 1 (1:1)

2 Lever - Gear 2 (1:1.4)

3 Mounting Clamp

4 Fine Adjustment Screw for cable tension

Mounting Notes:

• The thumb shifter is designed for installation on the right ‑ hand side of the handlebar.

DANGER!
Operation of other components, especially the brake lever, must not interfere with the thumb shifter.

WARNING!
Position the shifter such that the rider’s right hand remains on the grip and can operate both shift levers using only the thumb.

CAUTION!
Operation of the shift levers must not cause collision with adjacent components.

• The installation of the thumb shifter is permitted on either side of the brake clamp.

6.5 Cable Routing Requirements

WARNING!
Not following the cable routing requirements can lead to malfunction of the UTgear H2 or other bicycle components.

The following requirements must be met during integration:

• The cable housing must use a recommended cable diameter of 1.2mm. For optimal shifting performance, cable housing with good sliding properties is recommended.
• Route the shift-cable along the underside of the handlebar, ensuring unrestricted positional adjustment of the shifter without bending, kinking, or tensile loading.
• Observe minimum cable bending radii of 50mm.

DANGER!
Full steering range must remain unrestricted.

• Steering movement must not subject the cable system to tensile load, compression, kinking, or abrasion.

WARNING!
Suspension movement must remain uninhibited.

• Cable routing must prevent any interference or damage resulting from suspension compression.
• Cables must not be pinched or trapped at any point along the routing path.
• Route cables to avoid contact or abrasion against the gearbox, frame, or adjacent components.
• Cable must be routed in a way that allows it to enter the gearbox as smoothly and unobstructed as possible (see image below).

7 Compliance & Certification

• DIN EN ISO 4210-8:2023-05 (08.05.2026)

8 Revision History

9 Contact & Support

Universal Transmissions GmbH

Walkmühlenstraße 195

99974 Mühlhausen

E-mail: service@utgear.de

Website: www.utgear.de

10 Related Documentation

• Offer drawings / interface drawings
• CAD data package
• Installation instructions