ToolInfoBox Chainring Straightening Tool

Synonyms:	DE:Richtwerkzeug für Kettenblätter und Kurbelsterne
Location:	Bike Lounge

VAR #940 Chainring & Disc Brake Rotor Straightening Tool

1. Overview & Purpose

The VAR #940 is a professional-grade shop tool designed for straightening bent chainrings, crankset spiders, and disc brake rotors. It provides mechanics with the necessary leverage to correct lateral runout (wobbles) directly on the bicycle without removing the components.

2. Technical Specifications

Manufacturer: VAR Tools (France)
Model/Part Number: 940
Material: Heavy-duty, hardened tool steel
Handle: High-traction, ergonomic grip (classic orange/black vinyl)
Working Ends: Dual-slotted head with two distinct slot widths

3. Key Features

Dual-Slot Design:
- Narrow Slot: Optimized for individual chainring teeth, thin chainring bodies, and standard disc brake rotors.
- Wide Slot: Designed for thicker aluminum/steel chainrings and crankset spider arms.
High Leverage: The long handle minimizes physical effort required to bend hardened materials back into alignment.
Component Protection: Precision-machined slots distribute pressure evenly to prevent scratching, marring, or flattening of teeth.

4. Standard Operating Procedure (SOP)

For Chainrings:

Identify the Bend: Spin the crankset and visually locate the exact spot where the chainring wobbles or rubs against the front derailleur.
Position the Tool: Slide the appropriate slot of the VAR #940 over the bent section or tooth.
Apply Pressure: Apply gentle, controlled leverage in the opposite direction of the bend. Note: Always practice incremental adjustments—bend a little, check, and repeat if necessary.
Verify: Spin the crank again to ensure proper alignment and smooth chain clearance.

For Disc Brake Rotors:

Locate the Rub: Look through the brake caliper assembly while spinning the wheel to find the high spot rubbing against the brake pads.
Engage: Place the narrow slot over the affected area of the rotor track.
Correct: Apply minimal force to true the rotor. Note: Rotors are highly sensitive; use very light pressure.

5. Safety & Maintenance

       Safety Warning: Wear protective eyewear. Keep fingers clear of the chainring teeth and chain to avoid pinch hazards. Never use this tool on carbon fiber components.

Maintenance: Wipe the tool down after use with a clean rag.
Rust Prevention: Periodically apply a light coat of anti-corrosion oil to the bare steel slots.

Chainring Straightening Tool