Comparison
255/45 R20 vs 295/40 R20
Stepping from 255/45 R20 to 295/40 R20 keeps the 20-inch wheel but widens the section by 40 mm. This tire combination keeps overall diameter very close to stock. Dashboard speed shifts only marginally — within the noise of normal OEM tolerance. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeReasonable performance-leaning swap as long as fender and suspension clearance check out.
Quick math: 295/40 R20 is 6.5 mm taller than 255/45 R20, shifting the speedometer by +0.88%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+6.5 mm
0.88%
Speedometer at 100
100.9 km/h
+0.88% error
Ground clearance
+3.3 mm
ride height delta
Sidewall change
+3.3 mm
revs/km: 427.8
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/compare/255-45-r20-vs-295-40-r20Detailed comparison
| Metric | 255/45 R20 | 295/40 R20 | Difference |
|---|---|---|---|
| Overall diameter | 737.5 mm | 744.0 mm | +6.5 mm (+0.88%) |
| Sidewall height | 114.8 mm | 118.0 mm | +3.3 mm |
| Circumference | 2.317 m | 2.337 m | +20.4 mm |
| Revs / km | 431.6 | 427.8 | -3.8 |
| Ground clearance | reference | +3.3 mm | +3.3 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 100.9 km/h | +0.88 km/h |
Verdict: excellent
Within ±3% — speedometer, ABS and traction control should behave normally.
Speedometer impact
At a true 100 km/h, your dashboard will read 100.9 km/h after switching to 295/40 R20 — a +0.88% offset. Use the speedometer error calculator to recheck for other indicated speeds, and the speedometer error guide for the full background.
Ground clearance change
The new tire's half-diameter changes ride height by +3.3 mm. Small differences are absorbed by suspension travel, but anything beyond ±10 mm can affect headlight aim, fender clearance and bump-stop margin. See the plus-sizing guide before committing.
Back to
255/45 R20
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295/40 R20
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