Fitment Help

Why Fitment Matters

Getting your fitment right isn’t just about looks—it’s about performance, safety, and drivability. Proper wheel and tire fitment ensures clearance for brakes and suspension, reduces premature tire wear, and keeps your handling balanced on and off the track. Whether you’re going for a flush street stance or a motorsport-ready setup, this guide breaks down everything you need to know before you buy.

1. Understanding Wheel Fitment Basics

Wheel Size

  • Diameter (inches) – Must match your tire’s inner bead diameter (e.g., 18”, 19”).
  • Width (inches) – The distance between inner and outer wheel lips; affects tire stretch or bulge.

Offset (ET)

  • The distance (in mm) between the wheel’s mounting surface and its centerline.

    Positive offset (+) = wheel sits further in (common for OEM fitment).

    Negative offset (-) = wheel sits further out (more aggressive stance).

Bolt Pattern (PCD)

  • Defined by the number of lug holes and their spacing.
    Example: 5x114.3 = 5 lugs spaced 114.3mm apart.
  • Always match your vehicle’s hub and lug count.

Center Bore


  • The hole size in the center of the wheel that fits over your hub.

  • Use hub-centric rings if your wheel bore is larger than the hub to avoid vibration.

2. Tire Sizing 101

Tire sizes are displayed as Width / Aspect Ratio / Diameter — e.g., 245/40R18.

  • Width (245) = tire width in millimeters.
  • Aspect Ratio (40) = sidewall height as a percentage of width.
  • Diameter (18) = wheel diameter in inches.

Rule of thumb: Keep overall tire diameter within ±3% of OEM to avoid rubbing, ABS issues, and speedometer error.

3. How to Measure Fitment Properly

Step 1: Gather Your Current Specs

  • Check OEM size (sticker on door jamb or owner’s manual).
  • Measure clearance between tire and suspension components.

Step 2: Use Fitment Tools

  • Online calculators (e.g., willtheyfit.com) show how width and offset changes affect clearance.
  • Compare new vs. stock setup visually and dimensionally.

Step 3: Check Brake Clearance

  • Some performance brakes (e.g., Brembo, StopTech) require wheels with sufficient spoke clearance.
  • Verify with manufacturer fitment templates or diagrams before purchasing.

4. Common Fitment Terms Explained

  • Flush: Wheel face aligns with fender edge.
  • Poke: Wheel extends slightly beyond fender.
  • Tuck: Wheel sits inside fender line.
  • Staggered: Wider wheels/tires on the rear axle.
  • Square Setup: Same size wheels and tires on all corners.
  • Camber: Angle of wheels relative to vertical; negative camber tilts top inward for grip.

5. Avoiding Rubbing & Clearance Issues

Check Suspension Travel

  • Lowered cars have less clearance; measure compression travel before finalizing specs.

Rolling & Pulling Fenders

  • A mild fender roll adds a few mm of clearance.
  • Fender pulling reshapes metal for wider setups—use with caution.

Spacers

  • Can fine-tune offset for flush fitment.
  • Use hub-centric spacers with extended lugs for safety.

Coilover Clearance

  • Measure inside clearance from tire to coilover body.
  • Add at least 3–5mm of safety margin.

6. Fitment by Purpose

Street / Daily

  • Conservative offset for no-rub reliability.
  • Tire size close to OEM diameter.
  • Focus on comfort and durability.

Track / Performance

  • Square setup preferred for rotation and balance.
  • Slight negative camber for grip.
  • Higher-quality lightweight wheels reduce unsprung mass.

Show / Stance

  • Aggressive offset and stretched tires.
  • Requires camber adjustment and potential fender modification.
  • Prioritize aesthetics, but monitor clearance closely.

7. Recommended Brands for Wheels & Suspension

  • Wheels: Vossen, Rays, Enkei, BBS, Gram Lights, Forgestar.
  • Suspension: KW Suspension, Tein, Bilstein, Eibach, HKS.
  • Accessories: Project Kics, H&R, Whiteline (spacers, lugs, alignment kits).

8. Fitment Checklist Before You Order

  • Confirm bolt pattern & center bore.
  • Verify offset and width compatibility.
  • Check brake caliper clearance.
  • Ensure tire diameter within ±3% of stock.
  • Measure suspension and fender clearance.
  • Recalculate ride height and camber if lowered.

9. Frequently Asked Questions

Q: Can I run different wheel widths front and rear?

A: Yes, it’s called a staggered setup. It looks aggressive but limits tire rotation options.

Q: Do spacers affect handling?

A: Slightly—spacers widen track width, which can improve stability but may add stress on wheel bearings if excessive.

Q: What’s the largest tire I can fit?

A: Depends on offset, camber, and ride height. Measure physically or use online fitment comparison tools.

Q: Can aftermarket wheels affect warranty or alignment?

A: Not if installed correctly with hub-centric fitment and proper torque specs.

10. Final Thoughts

Getting your fitment right is the foundation of both performance and aesthetics. Take your time measuring, use reliable sources, and when in doubt—ask for expert guidance. Whether you’re dialing in coilovers or choosing the perfect set of wheels, proper fitment transforms how your car looks, feels, and drives.

Need personalized advice? Contact our team for expert fitment consultation and product recommendations based on your vehicle and goals.