WPL C74 KM Conversion – Complete Parts & Upgrade Guide

C74 Jimny - RTR - WPL RC Official Store

Converting a WPL C74 into a KM configuration is one of the most popular builds because it transforms the truck from a basic RTR into a more realistic, capable and durable platform.

This guide lists the essential parts you actually need, explains why each part matters, and helps you avoid buying unnecessary or incompatible components.

What Is a WPL C74 KM Build?

A “KM” build typically refers to:

  • A more scale-accurate high performance configuration

  • Improved durability over the stock plastic setup

  • Better compatibility with metal upgrades and drivetrain mods

Many first-time builders make the mistake of:

  • Buying parts in the wrong order

  • Missing critical supporting components

  • Mixing incompatible plastic and metal parts

This guide fixes that.

Stage 1: Required Parts (Do Not Skip)

These are mandatory if you want a reliable KM build.

🔧 Metal Upgrade Components

The stock plastic drivetrain is fine for light use, but a KM build adds:

  • Weight

  • Torque

  • Stress on axles and gears

Metal upgrades improve:

  • Durability

  • Steering precision

  • Long-term reliability

If you plan to drive outdoors or add further upgrades later, this is non-negotiable.

🔧 Steering Servo (Metal Gear Recommended)

KM builds are heavier than stock C74 setups.

A metal gear servo:

  • Handles added weight better

  • Provides more consistent steering

  • Lasts significantly longer than plastic gear servos

This is one of the most common failure points if left stock.

Stage 2: Drivetrain & Control Upgrades (Strongly Recommended)

These upgrades aren’t strictly required, but most KM builders install them early.

⚙️ Gearbox Considerations

Depending on your driving style:

  • Stock gearbox → simple, reliable

  • Dual-speed gearbox → low speed high speed gear best of both world

Dual-speed gearboxes are popular for KM builds because they allow:

  • Low-speed crawling

  • Higher trail speed without motor changes

🔊 Electronics & ESC Options

At this stage, many builders choose between:

  • Basic electronics (simple, quiet)

  • RES-V3 Sound system (realism-focused)

RES-V3 Sound systems significantly improve immersion, especially for military or scale builds, but are optional depending on preference.

Stage 3: Optional Scale & Realism Enhancements

Once the core build is complete, you can personalize the KM setup.

Common additions include:

  • Scale accessories

  • Lighting systems

  • Additional weight tuning

  • Cosmetic military details

These do not affect drivability, but greatly enhance realism.

Recommended Build Order (Simple Answer)

If you want the smoothest experience, follow this order:

1️⃣ Core metal upgrades
2️⃣ Metal gear steering servo
3️⃣ Gearbox upgrade (if desired)
4️⃣ Electronics / sound system
5️⃣ Cosmetic & scale details

Skipping ahead often causes compatibility or reliability issues later.

Parts List

Common Mistakes to Avoid

❌ Mixing metal and plastic drivetrain parts randomly
❌ Upgrading electronics before reinforcing the drivetrain
❌ Underestimating steering load on heavier builds
❌ Buying cosmetic parts before functional upgrades

A KM build rewards patience and planning.

Who Is This Build For?

A WPL C74 KM conversion is ideal if you:

  • Enjoy scale realism

  • Prefer durability over speed

  • Plan long-term upgrades

  • Want a platform that grows with you

If you only want casual indoor driving, a full KM conversion may be unnecessary.

Final Thoughts

The WPL C74 is popular because it’s modular and forgiving, but a proper KM build requires the right foundation.

This guide focuses on:

  • What’s actually required

  • What’s worth upgrading

  • What can wait

Build it once. Build it properly.