Evo 7/8/9: 18x8.5 +37 vs 18x9.5 +40 Wheel Fitment Comparison
For an Evo 7, Evo 8 or Evo 9, what changes when you move from 18x8.5 +37 to 18x9.5 +40? The second wheel is one inch wider, but also has a three-millimetre higher positive offset. Both numbers must be considered together: the wider rim reaches farther toward both the suspension and the outer guard.
This is a wheel-geometry companion to the main Mitsubishi Evo 7/8/9 fitment guide. It does not replace checking Brembo spoke clearance or verifying the exact tyre and suspension on your car.
Quick answer: 18x8.5 +37 versus 18x9.5 +40
The nominal bead-seat width grows by 25.4 mm (one inch). Half of that extra width—12.7 mm—would be added to each side at the same offset. Increasing positive offset from +37 to +40 then shifts the whole rim approximately 3 mm inward.
- Outer rim edge: the 18x9.5 +40 sits approximately 9.7 mm farther out than 18x8.5 +37.
- Inner rim edge: the 18x9.5 +40 sits approximately 15.7 mm farther in than 18x8.5 +37, leaving less nominal suspension-side space.
- Diameter: both are 18-inch rims, but the wheel barrel and spoke design can still differ substantially.
These calculations use nominal tyre bead-seat width and wheel offset. They do not measure outer flanges, mounted tyre shoulders, camber, brake hardware or real clearance.
Evo 7–9 wheel specification comparison table
| 5x114.3 example | Nominal width | Offset | Main consideration |
|---|---|---|---|
| 18x8.5 +37 | 8.5 inches | +37 mm | Narrower geometry; brake face must still be checked |
| 18x9.5 +40 | 9.5 inches | +40 mm | +9.7 mm outer and +15.7 mm inner extension versus 18x8.5 +37 |
| 18x9.5 +25 | 9.5 inches | +25 mm | At the same width, sits 15 mm farther outward than 18x9.5 +40 |
Notice that a higher positive offset does not necessarily mean a wider wheel has more inner clearance. Offset moves the centreline; additional width also matters.
How does this affect an Evo wheel purchase?
Outer guard and tyre clearance
Compared with 18x8.5 +37, an 18x9.5 +40 wheel's nominal bead seat reaches 9.7 mm farther toward the guard. Tyre shoulder width, tyre model, alignment, ride height, guard lip and suspension compression can change the real clearance. A tyre can extend beyond the bead-seat position used for these calculations.
Inner strut and suspension clearance
The same change takes up about 15.7 mm of additional space on the inner side of the rim. That makes checking spring perch, coilover, strut, arm and tyre clearance important, especially on a lowered Evo. Fitment that works at static ride height may not work through full steering or suspension travel.
Why Brembo brakes require a separate check
The spoke and inner-barrel shape—not width and offset alone—determines brake clearance. An 18x8.5 +37 wheel may have a different spoke profile from an 18x9.5 +40 wheel even within the same brand. The exact disc face and brake package must be checked. Read our Evo Brembo wheel-clearance guide for radial and axial checks, and the general brake-clearance checklist before buying.
Real genuine wheel specifications to compare
These current HausofWheels product examples show the dimensions discussed. They are not confirmed bolt-on Evo fitments; verify the exact car, brakes, wheel face, suspension and tyres before ordering. Availability can change.
- RAYS Gram Lights 57DR Dark Bronze, 18x8.5 +37, 5x114.3 — narrower-width reference.
- SSR GTX04 Dark Gunmetal, 18x9.5 +40, 5x114.3 — one-inch-wider, higher-offset reference.
- SSR Professor SP5 Flat Gunmetal, 18x9.5 +25, 5x114.3 — same nominal 9.5-inch width but a more outboard offset; the three-piece disc configuration also needs attention.
Browse the Evo 7 / 8 / 9 wheel collection or currently listed Sydney Stock. For a specification discussion, send HausofWheels your Evo year, exact front and rear brakes, suspension, tyre size and preferred wheel. We supply wheels only; no test-fitting or installation service is offered.
Frequently asked Evo 7–9 fitment questions
Does 18x9.5 +40 sit farther outward than 18x8.5 +37?
Yes. Despite its higher positive offset, the extra inch of width means its nominal outer bead-seat edge extends about 9.7 mm farther out.
Does 18x9.5 +40 provide more strut room?
No—not compared with 18x8.5 +37 at the same hub face. Its inner rim edge extends about 15.7 mm farther inward; the mounted tyre also needs separate measurement.
Does 18-inch 5x114.3 guarantee clearance of Evo 8 or Evo 9 Brembo calipers?
No. The correct PCD and diameter are necessary filters, but do not establish spoke-to-caliper or barrel clearance.
Can the Evo X guide be used for Evo 7–9?
Do not assume so. Brake equipment and fitment details can differ. See the separate Evo X guide.
The figures above are geometric comparisons, not installation approval or a guarantee of fitment. Confirm centre bore, correct nut seat and fasteners, wheel load rating, brake clearance and tyre/body clearance for the individual vehicle.