The Complete Guide to Wheel Offsets and Fitment

Confused about wheel offset, ET numbers, or fitment? Learn how to choose the perfect JDM wheels for your car — from flush fitment to deep concave setups.

Introduction: Why Wheel Fitment Matters

When upgrading your wheels, it’s not just about style — fitment and offset determine how your wheels sit on your car and affect handling, clearance, and performance. Understanding these terms is essential before you buy your next set of JDM wheels from Japan.

What Is Wheel Offset?

Wheel offset (ET) is the distance between the wheel’s mounting surface and its centerline. It’s measured in millimeters and determines how far the wheel sticks out or sits inwards in the wheel arch.

• Positive Offset (+): The mounting surface is toward the front (outer side) of the wheel.
  Common for most factory cars — wheels sit tucked inside the fender.
• Zero Offset (0): The mounting surface is exactly at the wheel’s centerline.
  Gives a balanced look, often seen on off-road or track setups.
• Negative Offset (–): The mounting surface is toward the back (inner side) of the wheel.
  Creates a deep-dish or concave look, popular in drift and stance culture.

How Offset Affects Fitment

Offset Type	Appearance	Typical Use	Effect on Car
Positive (+)	Tucked, factory look	Daily cars	Stable steering, safe clearance
Zero (0)	Neutral stance	Track & tuner builds	Balanced handling
Negative (–)	Aggressive, concave	Drift, widebody cars	Wider track, potential fender rub

Tip: Lower offset = wheel sits further out. Higher offset = wheel sits further in.

Understanding Wheel Fitment

Fitment describes how the wheel and tire align with the fenders. Perfect fitment isn’t only visual — it also ensures no rubbing, good suspension travel, and safe driving.

Types of fitment styles:

• OEM Fitment: Factory specs for daily reliability.
• Flush Fitment: Wheel edge aligns perfectly with the fender.
• Poke Fitment: Wheel lip extends slightly past the fender.
• Stretched Fitment: Narrow tire on wide rim — for stance style only.

How to Measure Correct Fitment

To find ideal fitment:

1. Check your car’s stock wheel specs.
   Example: 17x7J +45 (diameter x width + offset)
2. Decide your target stance.
   • Want a flush look? Slightly lower the offset (e.g., +40 → +35).
   • Widebody? You can go negative (e.g., +35 → +15).
3. Use a fitment calculator to compare before and after.
4. Test clearance around suspension, brakes, and fenders.

Common Mistakes to Avoid

• ❌ Ignoring brake caliper clearance.
• ❌ Using wrong tire sizes that rub the fender.
• ❌ Mixing offsets on AWD cars (can affect drivetrain).
• ❌ Not aligning after wheel changes.

Why Choose JDM Wheels for Perfect Fitment

Japanese brands like RAYS, WedsSport, Work, and Enkei are world-renowned for precision engineering.
They offer wide offset and width options to suit any setup — from daily drives to track monsters.

• RAYS Volk TE37: Lightweight forged, +22 to +45 options.
• Work Emotion CR Kiwami: Aggressive concave design with –5 to +38 offsets.
• WedsSport SA-72R: Balanced, ideal for street/track dual use.

All these can be found through Upgarage Japan, shipped directly from Japan with reliable quality.

Understanding offset and fitment helps you choose wheels that look great and perform safely.
Whether you’re going for a clean flush setup or a bold drift stance, the right wheel specs make all the difference.

Good mobility, Happy life!
Explore authentic JDM wheels and parts at Upgarage Japan today.