Comparison
255/35 R21 vs 265/35 R20
Minus-sizing from 255/35 R21 to 265/35 R20 pairs a smaller 20-inch wheel with more rubber between the rim and road. This sizing approach shifts overall diameter slightly from OEM. The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff. 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: 265/35 R20 is 18.4 mm shorter than 255/35 R21, shifting the speedometer by -2.58%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-18.4 mm
-2.58%
Speedometer at 100
97.4 km/h
-2.58% error
Ground clearance
-9.2 mm
ride height delta
Sidewall change
+3.5 mm
revs/km: 459.0
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/compare/255-35-r21-vs-265-35-r20Detailed comparison
| Metric | 255/35 R21 | 265/35 R20 | Difference |
|---|---|---|---|
| Overall diameter | 711.9 mm | 693.5 mm | -18.4 mm (-2.58%) |
| Sidewall height | 89.3 mm | 92.8 mm | +3.5 mm |
| Circumference | 2.236 m | 2.179 m | -57.8 mm |
| Revs / km | 447.1 | 459.0 | +11.9 |
| Ground clearance | reference | -9.2 mm | -9.2 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.4 km/h | -2.58 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 97.4 km/h after switching to 265/35 R20 — a -2.58% 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 -9.2 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
255/35 R21
Back to
265/35 R20
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