Comparison
225/50 R17 vs 245/40 R17
Going from 225/50 R17 to 245/40 R17 keeps the rim but tightens the sidewall for a sportier look. This sizing approach swings rolling diameter far enough to feel on the road.
The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. Less sidewall flex usually translates to crisper turn-in and a slightly stiffer ride over rough pavement. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff. The 3–5% diameter gap puts this in caution territory: doable on many cars, but verify clearance and consider recalibration.
TakeSuits drivers who value sharper steering and appearance over outright ride softness.
Quick math: 245/40 R17 is 29.0 mm shorter than 225/50 R17, shifting the speedometer by -4.42%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
-29.0 mm
-4.42%
Speedometer at 100
95.6 km/h
-4.42% error
Ground clearance
-14.5 mm
ride height delta
Sidewall change
-14.5 mm
revs/km: 507.0
Permalink for this comparison:
/compare/225-50-r17-vs-245-40-r17Detailed comparison
| Metric | 225/50 R17 | 245/40 R17 | Difference |
|---|---|---|---|
| Overall diameter | 656.8 mm | 627.8 mm | -29.0 mm (-4.42%) |
| Sidewall height | 112.5 mm | 98.0 mm | -14.5 mm |
| Circumference | 2.063 m | 1.972 m | -91.1 mm |
| Revs / km | 484.6 | 507.0 | +22.4 |
| Ground clearance | reference | -14.5 mm | -14.5 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 95.6 km/h | -4.42 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 95.6 km/h after switching to 245/40 R17 — a -4.42% 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 -14.5 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
225/50 R17
Back to
245/40 R17
Drivers also compare
Closely-related fitments and plus-size swaps for 225/50 R17 and 245/40 R17.
215/45 R17 vs 245/40 R17
Wider variation on the same rim — more grip, less clearance.
Δ 0.40%
225/50 R17 vs 245/45 R17
Wider variation on the same rim — more grip, less clearance.
Δ 0.69%
225/45 R17 vs 245/40 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.02%
245/40 R17 vs 255/40 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.27%
205/50 R17 vs 245/40 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.41%
215/50 R17 vs 225/50 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.55%
215/55 R17 vs 225/50 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.72%
205/45 R17 vs 245/40 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.87%
Related topics