235/65 R16

What size is 235/65 R16?

235/65 R16 has an overall diameter of about 28.03 in, a section width of 9.25 in and a sidewall height of 6.01 in. It turns roughly 720 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.

Fitment verdict

255/35 R21 stays within the configured tolerance for 235/65 R16: 0.0% diameter and 0.0% speedometer effect.

Metric This size: 235/65 R16 Alternative: 255/35 R21 Difference Verdict
Overall diameter 28.03 in 28.03 in 0.0% Within tolerance
Section width 9.25 in 10.04 in +0.79 in Computed difference
Sidewall height 6.01 in 3.51 in -2.50 in Computed difference
Circumference 88.05 in 88.05 in 0.0% Within tolerance
Speedo 0.0% 0.0% 0.0% Within tolerance

Seasonal check

Planning a long summer drive?

Use the budget and running-cost tools before a trip, especially if the current tyres are worn or the replacement size changes diameter.

Estimate tyre budget

Specification

Overall diameter28.03 in
Section width9.25 in
Sidewall height6.01 in
Circumference88.05 in
Revolutions 447 /km · 720 /mi

In-tolerance sizes

Alternative sizes that stay within the safe diameter tolerance:

Size Diameter Speedo Verdict
255/35 R21 +0.0% +0.0% ✓ OK
255/45 R19 +0.0% +0.0% ✓ OK
215/65 R17 -0.1% -0.1% ✓ OK
235/60 R17 +0.3% +0.3% ✓ OK
235/55 R18 +0.5% +0.5% ✓ OK
235/50 R19 +0.8% +0.8% ✓ OK
225/55 R18 -1.0% -1.0% ✓ OK
245/45 R19 -1.2% -1.2% ✓ OK
275/40 R19 -1.3% -1.3% ✓ OK
225/60 R17 -1.4% -1.4% ✓ OK
225/65 R17 +1.7% +1.7% ✓ OK
225/65 R16 -1.8% -1.8% ✓ OK

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.0% (+0.00 in) · US (~3%)
  • Within tolerance · Diameter +0.0%.
  • Speedo @ 60: 60 mph60.0 mph.
  • Sidewall -2.50 in · Width +0.79 in.
Diameter+0.0%+0.00 in
Speedo @ 60+0.0%60 mph60.0 mph
Sidewall-2.50 inWidth +0.79 in
How this result is calculated

Computed from nominal tire-size geometry: diameter, circumference and speedometer error. It does not check wheel-arch, suspension or brake clearance.

Methodology
Diameter
28.03 in 28.03 in+0.00 in
Sidewall
6.01 in 3.51 in-2.50 in
Width
9.25 in 10.04 in+0.79 in
Circumference
88.05 in 88.05 in+0.0%
Revs / mile
720 720
Speedo @ 60
60 mph 60.0 mph+0.0%
Δ⌀ +0.0 mm
  • Current235/65 R16
  • New255/35 R21
  • Grounded to the road: the axle rises +0.00 in.

Result report

235/65 R16 255/35 R21 · Within tolerance

Use this size when shopping: 255/35 R21

Use this size when shopping

Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 255/65R15+0.1%+0.1%
OE 235/65R16+0.0%+0.0%
+1″ 175/80R17-0.0%-0.0%
+2″ 255/50R18+0.0%+0.0%

More tools

Last reviewed: 2026-06-28

Last reviewed: 2026-06-28
What changed
  • Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.