PER DAUN/LEAF SPRING
to PER KEONG/MULTI LINK
of VEHICLE (TRUCK etc.) SUSPENSION MECHANISM CONVERSION

on

"a very complete every step-by-step of work done stages VIDEO"

Adding 4 Link Suspension to the Chevy Muscle Truck! | Roadkill Garage


VISUAL DIAGRAM

4 LINK  /  MULTI LINK

SUSPENSION CONVERSION of A 4WD SUZUKI

Installing 4 Link suspension on my Samurai #fabrication #cncplasma #offroad



CHAT GPT

🔧 IMPORTANT EMPHASIZEMENT REMINDER!

THE USE of TORSION BAR TUBE

"— this is getting fabrication & chassis engineering territory."

When people talk about using a torsion bar tube in a custom 4-link / multi-link conversion, they usually mean using the tube as a

structural crossmember

not as a torsion spring (ex. old VW Beetle suspension).

Let’s break it down properly.

1. What is a Torsion Bar Tube?

Originally, a thick steel tube welded into the chassis that houses torsion bars (spring function) and acts as a major structural crossmember (e.g., classic VW Beetle rear housing).

"In custom builds, fabricators reuse the concept: A large diameter tube welded across the chassis to act as a rigid mounting structure."

2. Why Use a Torsion Bar Tube in 4-Link/MULTI-LINK Conversions?

When converting leaf spring → 4-link (common on Jimny, Taft, CJ, etc.), you need a rock-solid foundation for:

  • Upper and lower link mounts
  • Coilover mounts
  • Panhard / triangulated link geometry support
  • Anti-squat geometry control

The tube functions as:

  • Structural Crossmember: Connects frame rails and prevents frame twist (crucial for ladder frames).
  • Upper Link Mount Platform: Provides a strong, centralized anchor point for centered links.
  • Coilover Tower Base: Essential for high-leverage, long-travel setups.
⚠️ Technical Note

There is a conceptual difference:

4-link → very specific suspension geometry term
Multi-link → broader term (can include IRS independent systems)
In solid axle off-road context, 4-link is already a type of multi-link.

3. Structural Advantages

Compared to flat plate crossmembers, round tubes distribute stress better and offer:

  • Higher torsional rigidity
  • Less stress concentration
  • Superior fatigue resistance in off-road use

4. Important Engineering Considerations ⚠️

A. Link Geometry Comes First: Tube placement must respect Instant Center, Anti-squat %, Roll center, and Driveshaft angles. If the tube is placed wrong, the vehicle will handle poorly or dangerously.

B. Welding to Ladder Frame

For vehicles like the Suzuki Jimny or Jeep Wrangler, you must:

  • Box the frame first if the steel is thin.
  • Use fish plates / reinforcement gussets.
  • Avoid heat warping the rails during the welding process.

5. Professional Recommendations

If building for plantation terrain or heavy diesel torque (Indonesian off-road style):

  • Material: Use DOM tubing (not mild "water pipe").
  • Thickness: 3–5 mm wall thickness minimum.
  • Integration: Tie into the roll cage if it's an extreme build.

🔧 SUMMARY

✅ 

Structurally sound if engineered properly


✅ 

Excellent for torsional rigidity


❌ 

Dangerous if done without geometry & load analysis


Comments

Post a Comment