Comparison
225/45 R18 vs 245/35 R20
Plus-sizing from 225/45 R18 to 245/35 R20 keeps overall diameter close to factory while opening room for a larger 20-inch wheel. This alternative fitment swings rolling diameter far enough to feel on the road.
Indicated speed will drift far enough that recalibration is worth considering. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. The wider section adds contact patch and lateral stability, while eating into fender and suspension clearance. Many drivers pick this direction primarily for appearance — the bigger rim simply looks more aggressive. The 3–5% diameter gap puts this in caution territory: doable on many cars, but verify clearance and consider recalibration.
TakeCommon upgrade for sportier handling and a tighter wheel-gap look on the same vehicle.
Quick math: 245/35 R20 is 19.8 mm taller than 225/45 R18, shifting the speedometer by +3.00%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+19.8 mm
3.00%
Speedometer at 100
103.0 km/h
+3.00% error
Ground clearance
+9.9 mm
ride height delta
Sidewall change
-15.5 mm
revs/km: 468.4
Permalink for this comparison:
/compare/225-45-r18-vs-245-35-r20Detailed comparison
| Metric | 225/45 R18 | 245/35 R20 | Difference |
|---|---|---|---|
| Overall diameter | 659.7 mm | 679.5 mm | +19.8 mm (+3.00%) |
| Sidewall height | 101.3 mm | 85.8 mm | -15.5 mm |
| Circumference | 2.073 m | 2.135 m | +62.2 mm |
| Revs / km | 482.5 | 468.4 | -14.1 |
| Ground clearance | reference | +9.9 mm | +9.9 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.0 km/h | +3.00 km/h |
Verdict: warning
Between 3% and 5% — noticeable speedometer drift; recalibration may be advisable.
Speedometer impact
At a true 100 km/h, your dashboard will read 103.0 km/h after switching to 245/35 R20 — a +3.00% 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 +9.9 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
225/45 R18
Back to
245/35 R20
Drivers also compare
Closely-related fitments and plus-size swaps for 225/45 R18 and 245/35 R20.
245/35 R20 vs 285/30 R20
Wider variation on the same rim — more grip, less clearance.
Δ 0.07%
225/45 R18 vs 255/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.23%
225/45 R18 vs 245/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.99%
245/35 R20 vs 255/35 R20
Wider variation on the same rim — more grip, less clearance.
Δ 1.03%
225/45 R18 vs 235/45 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.36%
215/45 R18 vs 225/45 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.38%
225/45 R18 vs 265/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.44%
225/45 R18 vs 275/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.52%
Related topics