Comparison
275/35 R21 vs 295/40 R20
Minus-sizing from 275/35 R21 to 295/40 R20 pairs a smaller 20-inch wheel with more rubber between the rim and road. 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. Extra sidewall absorbs impacts more readily — a sensible bias for daily commuting and broken pavement. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.
Quick math: 295/40 R20 is 18.1 mm taller than 275/35 R21, shifting the speedometer by +2.49%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+18.1 mm
2.49%
Speedometer at 100
102.5 km/h
+2.49% error
Ground clearance
+9.1 mm
ride height delta
Sidewall change
+21.8 mm
revs/km: 427.8
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/compare/275-35-r21-vs-295-40-r20Detailed comparison
| Metric | 275/35 R21 | 295/40 R20 | Difference |
|---|---|---|---|
| Overall diameter | 725.9 mm | 744.0 mm | +18.1 mm (+2.49%) |
| Sidewall height | 96.3 mm | 118.0 mm | +21.8 mm |
| Circumference | 2.280 m | 2.337 m | +56.9 mm |
| Revs / km | 438.5 | 427.8 | -10.7 |
| Ground clearance | reference | +9.1 mm | +9.1 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 102.5 km/h | +2.49 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 102.5 km/h after switching to 295/40 R20 — a +2.49% 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 +9.1 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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275/35 R21
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295/40 R20
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