Road Bike Shift Cable Outer Casing and Inner Wire Buying Guide: Optislick vs Coated Cables

Road Bike Gear Cable & Housing Buying Guide

Gear cables are one of the most overlooked consumables on a bicycle. A good set of cables can make shifting feel as smooth as electronic shifting, while a worn-out set can make even a top-tier derailleur feel sluggish. This article takes an in-depth look at the technical differences between various cables.

Gear Cable Basic Structure

A complete gear cable set consists of two parts:

Inner Cable

• Material: Stainless steel multi-strand twisted wire
• Diameter: 1.1mm or 1.2mm
• Structure: Made of multiple thin steel wires twisted together, typically 19 strands
• End: Features a barrel-shaped terminal for anchoring

Outer Cable Housing

• Structure: Coiled steel wire + inner liner + outer casing
• Outer diameter: 4mm (for shifting) or 5mm (for braking, not covered in this article)
• Inner liner: The key component determining smoothness

Inner Cable Coating Technology Comparison

1. Basic Stainless (Uncoated)

• Features: The most basic stainless steel cable
• Coefficient of friction: Approx. 0.3-0.4
• Price: NT$50-100 per cable
• Lifespan: Approx. 3,000-5,000 km

2. Shimano Optislick

• Features: Silicone resin coating, greyish-green appearance
• Coefficient of friction: Approx. 0.15-0.2
• Price: NT$150-200 per cable
• Lifespan: Approx. 5,000-8,000 km
• Feel: Noticeably smoother than uncoated cables; Shimano’s mainstream cable

3. Shimano Polymer Coated Cable

• Features: PTFE (Teflon) coating, dark green appearance
• Coefficient of friction: Approx. 0.08-0.12
• Price: NT$300-400 per cable
• Lifespan: Approx. 5,000-8,000 km
• Feel: Extremely smooth, close to electronic shifting
• Note: The coating is relatively fragile and can be easily scratched when tightening the fixing bolt

4. Jagwire Pro Polished

• Features: Mechanically polished + Teflon coating
• Coefficient of friction: Approx. 0.1-0.15
• Price: NT$200-300 per cable
• Lifespan: Approx. 5,000-8,000 km

5. Campagnolo Ultra-Shift Specific Cable

• Features: Zinc-plated + PTFE coating
• Coefficient of friction: Approx. 0.1-0.15
• Price: NT$400-500 per cable
• Note: Specifically designed for Campagnolo systems; the inner cable terminal has a different shape

Coefficient of Friction Comparison Overview

Cable Type	Coefficient of Friction	Relative Smoothness	Price Range
Uncoated Stainless	0.3-0.4	★★☆☆☆	NT$50-100
Optislick	0.15-0.2	★★★☆☆	NT$150-200
Jagwire Pro	0.1-0.15	★★★★☆	NT$200-300
Shimano Polymer	0.08-0.12	★★★★★	NT$300-400
Campagnolo PTFE	0.1-0.15	★★★★☆	NT$400-500

In-Depth Housing Structure Analysis

Standard Coiled Housing

• Structure: Flat steel wire wound in a spiral
• Features: Can be bent but cannot be compressed (suitable for shifting)
• Inner liner: Plastic tube that determines friction with the inner cable

Shimano SP41 Housing

• Inner liner: SIL-TEC low-friction liner
• Features: Shimano factory standard; good smoothness
• Price: NT$250/m
• Compatibility: Best paired with Optislick or Polymer inner cables

Jagwire LEX-SL Housing

• Inner liner: Teflon liner
• Features: Thicker, more robust liner with better water resistance
• Price: NT$200/m

Yokozuna Reaction Housing

• Inner liner: Ultra-low-friction liner
• Features: Japanese brand with an excellent reputation
• Price: NT$350/m

Impact of Housing Length and Cable Routing

Poor shifting feel is often not a cable quality issue but rather incorrect housing length and cable routing:

Housing Too Long

• Increases the number of bends, raising friction resistance
• Looks untidy
• May cause unnecessary rubbing against the frame

Housing Too Short

• Pulls the inner cable during steering, causing “ghost shifting”
• Places excessive tension on the cable, accelerating wear
• Affects steering responsiveness

How to Determine Correct Length

1. Turn the handlebar to its maximum angle (once on each side)
2. The housing should maintain a natural curve without being pulled taut
3. There should also be no excessive slack loops
4. Housing at the fork should move smoothly without catching during steering

When to Replace

Inner Cable Replacement Indicators

• Sluggish shifting: Noticeable delay in derailleur response after pulling the shift lever
• Poor return: Derailleur fails to return properly after releasing the lever
• Cable wear: Burrs or broken strands on the inner cable (inspect visually at the fixing bolt)
• Corrosion: Rust spots appearing on the inner cable surface
• Mileage: Generally recommended to replace every 5,000-8,000 km

Housing Replacement Indicators

• Casing cracking: Cracks appearing in the plastic outer casing
• Liner wear: Cut open the housing end to check whether the liner has worn flat
• Crushing or deformation: Visible flattening or kink marks on the housing
• Time: Even with low mileage, replacement is recommended after more than 2 years (plastic aging)

Installation Tips

Housing Cutting

1. Use a dedicated cable cutter (not regular pliers) to ensure a clean, square cut
2. After cutting, dress the end face with a file or sandpaper
3. Confirm the liner has not been crushed or blocked
4. Install housing end caps (ferrules) to protect the cut end

Inner Cable Installation

1. Apply a thin layer of low-viscosity grease to the inner cable before threading
2. When threading, confirm there is no catching as the cable passes through all housing sections
3. Fixing bolt torque: 6-8 Nm (overtightening will crush the coating on coated cables)
4. Install a cable end cap on the tail to prevent fraying

Special Notes for Polymer Coated Cables

For Shimano Polymer coated cables, the coating must be stripped at the fixing bolt; otherwise:

• The coating will slip under bolt pressure, causing the cable to loosen
• Shifting adjustments will drift as the coating compresses

Correct procedure: Use a utility knife to lightly scrape off about 1cm of coating near the fixing point, exposing the bare stainless steel cable before tightening.

Buying Recommendations

Entry to Mid-Range Bikes

Recommended: Shimano Optislick + SP41 Housing

• Best value-for-money combination
• Full set (front and rear derailleurs) approx. NT$600-800
• Smoothness is sufficient for 105 to Ultegra level derailleurs

High-End Bikes

Recommended: Shimano Polymer + SP41 Housing

• Top-tier smoothness, best paired with Dura-Ace derailleurs
• Full set approx. NT$1,000-1,200
• Pay attention to coating treatment during installation

Campagnolo Systems

Recommendation: Campagnolo OEM Cable Kits

• The cable end terminals differ in shape from Shimano/SRAM and are not interchangeable
• OEM cable kits ensure optimal compatibility

Conclusion

Shift cables may seem insignificant, but they directly affect the feel of every gear change. Regularly replacing cables (recommended every 5,000-8,000 km or once a year) is fundamental to maintaining your shifting system in top condition. Investing in a good set of cables costs only a few hundred NT dollars, yet delivers an immediate improvement in feel—this may be one of the highest value-for-money upgrades in bicycle maintenance.

Related Reading

• When and How to Replace Bicycle Cables: Managing the Lifespan of Brake and Shift Cables
• The Complete Guide to Internal Cable Routing: From Route Planning to Threading Techniques
• The Ultimate Guide to Road Bike Internal Cable Routing Systems: Threading Tools and Techniques
• The Complete Road Bike Wheelset Guide: A Comprehensive Comparison of Aluminum, Carbon, Tubular, and Tubeless