235/70 R17

What size is 235/70 R17?

235/70 R17 has an overall diameter of about 29.95 in, a section width of 9.25 in and a sidewall height of 6.48 in. It turns roughly 673 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.

Fitment verdict

235/65 R18 stays within the configured tolerance for 235/70 R17: +0.2% diameter and +0.2% speedometer effect.

Metric This size: 235/70 R17 Alternative: 235/65 R18 Difference Verdict
Overall diameter 29.95 in 30.03 in +0.2% Within tolerance
Section width 9.25 in 9.25 in 0.00 in Computed difference
Sidewall height 6.48 in 6.01 in -0.46 in Computed difference
Circumference 94.10 in 94.33 in +0.2% Within tolerance
Speedo 0.0% +0.2% +0.2% 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 diameter29.95 in
Section width9.25 in
Sidewall height6.48 in
Circumference94.10 in
Revolutions 418 /km · 673 /mi

In-tolerance sizes

Alternative sizes that stay within the safe diameter tolerance:

Size Diameter Speedo Verdict
235/65 R18 +0.2% +0.2% ✓ OK
255/50 R20 +0.3% +0.3% ✓ OK
255/65 R17 +0.3% +0.3% ✓ OK
285/35 R22 -0.3% -0.3% ✓ OK
275/45 R20 -0.7% -0.7% ✓ OK
305/40 R20 -1.2% -1.2% ✓ OK
245/60 R18 -1.3% -1.3% ✓ OK
265/40 R22 +1.3% +1.3% ✓ OK
245/65 R17 -1.4% -1.4% ✓ OK
265/45 R21 +1.5% +1.5% ✓ OK
245/70 R16 -1.5% -1.5% ✓ OK
265/50 R20 +1.6% +1.6% ✓ OK

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.2% (+0.07 in) · US (~3%)
  • Within tolerance · Diameter +0.2%.
  • Speedo @ 60: 60 mph60.1 mph.
  • Sidewall -0.46 in · Width +0.00 in.
Diameter+0.2%+0.07 in
Speedo @ 60+0.2%60 mph60.1 mph
Sidewall-0.46 inWidth +0.00 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
29.95 in 30.03 in+0.07 in
Sidewall
6.48 in 6.01 in-0.46 in
Width
9.25 in 9.25 in+0.00 in
Circumference
94.10 in 94.33 in+0.2%
Revs / mile
673 672
Speedo @ 60
60 mph 60.1 mph+0.2%
Δ⌀ +1.9 mm
  • Current235/70 R17
  • New235/65 R18
  • Grounded to the road: the axle rises +0.04 in.

Result report

235/70 R17 235/65 R18 · Within tolerance

Use this size when shopping: 235/65 R18

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 295/60R16-0.1%-0.1%
OE 235/70R17+0.0%+0.0%
+1″ 275/55R18-0.1%-0.1%
+2″ 185/75R19-0.1%-0.1%

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.