Comparison
205/70 R15 vs 245/45 R17
245/45 R17 is a plus-2 alternative to 205/70 R15 — the bigger wheel shows through a thinner sidewall. This alternative fitment moves rolling diameter a touch off the original spec. The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 245/45 R17 is 15.7 mm shorter than 205/70 R15, shifting the speedometer by -2.35%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-15.7 mm
-2.35%
Speedometer at 100
97.6 km/h
-2.35% error
Ground clearance
-7.9 mm
ride height delta
Sidewall change
-33.3 mm
revs/km: 488.0
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/compare/205-70-r15-vs-245-45-r17Detailed comparison
| Metric | 205/70 R15 | 245/45 R17 | Difference |
|---|---|---|---|
| Overall diameter | 668.0 mm | 652.3 mm | -15.7 mm (-2.35%) |
| Sidewall height | 143.5 mm | 110.3 mm | -33.3 mm |
| Circumference | 2.099 m | 2.049 m | -49.3 mm |
| Revs / km | 476.5 | 488.0 | +11.5 |
| Ground clearance | reference | -7.9 mm | -7.9 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.6 km/h | -2.35 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 97.6 km/h after switching to 245/45 R17 — a -2.35% 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 -7.9 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.
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205/70 R15
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245/45 R17
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