RISK RL255 Rear Derailleur B-Tension Adjustment Gauge for 12-Speed Road Di2, Road 12-speed electronic rear derailleurs

RISK RL255 Rear Derailleur B-Tension Adjustment Gauge for 12-Speed Road Di2, Road 12-speed electronic rear derailleurs

The RISK RL255 Road 12-Speed Electronic Rear Derailleur Adjustment Gauge is a practical setup tool designed to help adjust the rear derailleur B-tension screw on compatible 12-speed road electronic shifting systems. It helps align the guide pulley position with the largest cassette sprocket, making derailleur setup more accurate and easier during bike assembly, drivetrain maintenance, or cassette replacement.

The RL255 uses a 2-in-1 reference design. One side is marked for compatible R7100 / R7150 / RX820 series rear derailleurs, and the other side is marked for compatible R8150 / R9250 series rear derailleurs. It includes reference markings for common cassette sprocket sizes such as 28T, 30T, 34T, and 36T, helping mechanics quickly find the correct adjustment position.

Made from lightweight polymer material using a 3D printing process, this gauge is compact, easy to carry, and suitable for workshop, store, and home mechanic use.

Note: This product includes the adjustment gauge only. Rear derailleur, cassette, bicycle, and other parts shown in images are for display only and are not included. 3D-printed products may have visible layer lines or seam marks; these are normal process characteristics and do not affect use.

Key Features

• Designed for 12-speed road electronic rear derailleur B-tension adjustment
• Helps set the guide pulley distance from the largest cassette sprocket
• 2-in-1 design for multiple compatible derailleur series
• Reference markings for 28T / 30T / 34T / 36T cassette sprockets
• Suitable for compatible R7100 / R7150 / RX820 / R8150 / R9250 road 12-speed systems
• Lightweight polymer construction
• 3D printed production process
• Compact and easy to carry
• Available in 1-piece and 2-piece packs
• Ideal for bike shops, mechanics, and home maintenance

Product Specifications

Compatibility Reference

Compatibility information is for reference only. Please confirm your rear derailleur and cassette specifications before purchase.

Product Options

1. RL255 Adjustment Gauge — 1 pc Pack

Quantity: 1 pc / bag

Color: Blue

Material: Polymer / Plastic

Net Weight: Approx. 6.4g

Gross Weight: Approx. 7.8g

Package Size: Approx. 8 × 10 × 0.4 cm

Use: Single tool for individual riders, home mechanics, and daily workshop use.

2. RL255 Adjustment Gauge — 2 pcs Pack

Quantity: 2 pcs / bag

Color: Blue

Material: Polymer / Plastic

Net Weight: Approx. 12.8g

Gross Weight: Approx. 14.2g

Package Size: Approx. 17 × 10 × 0.4 cm

Use: Backup set or shop/workshop pack for frequent maintenance.

Accurate B-Tension Setup

Helps adjust the B-tension screw and guide pulley position for smoother drivetrain setup on compatible 12-speed road electronic systems.

2-in-1 Reference Design

One gauge supports multiple compatible derailleur series, including reference zones for R7100 / R7150 / RX820 and R8150 / R9250 series.

Clear Cassette Markings

Printed reference lines for 28T, 30T, 34T, and 36T cassette sprockets make adjustment more intuitive.

Lightweight & Portable

Compact size and light polymer construction make it easy to carry in a toolbox or workshop drawer.

Workshop & Home Mechanic Friendly

Useful for bike shops, mechanics, and riders who maintain or upgrade their own drivetrain.

How to Use

1. Shift the chain to the smallest chainring and the largest cassette sprocket.
2. Place the RL255 gauge near the rear derailleur guide pulley and largest cassette sprocket.
3. Select the correct reference marking according to your rear derailleur model and cassette sprocket size.
4. Adjust the B-tension screw until the largest sprocket aligns with the corresponding curved reference line.
5. Check shifting performance after adjustment.

Always refer to the original drivetrain manufacturer’s service manual for final setup specifications.

3D Printing Process Notice

This product is made using a 3D printing process. Visible layer lines, seam marks, or slight surface texture are normal production characteristics and are not quality defects. These do not affect function or durability under normal use.

Available Options

Each row below is one available option combination. Choose the complete combination that matches your setup.