Which derailleur limit screw driver do I need — 3mm or 6mm?

Start with the 3mm — it fits most Shimano and SRAM derailleur limit screws. The 6mm flat blade is better suited for cable clamp bolts and wider flat-head fasteners on older components. Having both covers all common bicycle flat-head applications.

Are derailleur limit screws the same as indexing adjustment?

No — they are two different adjustments. Limit screws (H and L) set the physical travel range to prevent over-shift. Indexing is adjusted via the barrel adjuster and sets the precise cable tension for each gear click. Both are important for smooth shifting.

IceToolz

Icetoolz 3mm Flat Blade Screwdriver with Magnetic Tip

Name: Icetoolz 3mm Flat Blade Screwdriver with Magnetic Tip
Brand: IceToolz
SKU: CMB_EAS_4718152282835
Price: 590.00 INR
Availability: InStock
Author: InstaSport Editorial

₹590.00

Description

The IceToolz 3mm Flat Blade Screwdriver with Magnetic Tip is a narrow flat blade screwdriver purpose-built for the small flat-head screws common on bicycle derailleurs, particularly limit screws. Most Shimano and SRAM derailleur limit screws (H and L adjustment) accept a 3-4mm flat blade — this 3mm