Sheet TS-C01Rev. Oct 15, 2026United States · Canada

Data sheet TS-C01 · Comparison

275/55R20 vs 275/60R20

275/60R20 measures 33.0 in (838 mm) overall, +3.4% or +1.08 in versus 275/55R20 at 31.9 in (811 mm). It raises axle clearance by 0.54 in (14 mm) and drops revs per mile 632 → 611.

Input

Accepts 265/70R17, LT265/70R17 121S, 265 70 17 or 33x12.50R15.

Fig. 1 — Cross-section, size 2

D33.0″B6.5″C20″A10.8″
275/60R20: A section width, B sidewall, C rim, D overall diameter. Nominal, on the measuring rim.

Table 1 — Data

275/60R20 is 32.99″ tall, +3.39% against 275/55R20. At 60 mph on the dial you drive 62.0 mph.

275/55R20 vs 275/60R20
Item275/55R20275/60R20Change
Overall diameter31.91″32.99″+3.39%
Section width10.83″10.83″0.00″
Sidewall5.95″6.50″+0.54″
Rim20″20″same
Revs per mile632611−21
Dial 60 mph =60.062.0+3.4%
Axle height15.95″16.50″+0.54″

+3.39% — outside the ±3% rule of thumb tire shops use. Expect a speedometer error, and check clearance at full lock and full compression before you buy.

Where to buy 275/60R20 ↓

Fig. 2

Side view and width, to scale

Size 1 dashed, size 2 solid, on one ground line.

31.9″33.0″+0.54″

275/55R20275/60R20

Table 2 — Speedometer

Speedometer reading and true speed
Dial showsTrue speedDifference
30 mph31.0 mph+1.0
45 mph46.5 mph+1.5
60 mph62.0 mph+2.0
70 mph72.4 mph+2.4
80 mph82.7 mph+2.7

Engine RPM at the same road speed: −3.3%. Gear ratio calculator

Table 3

Published dimensions

From each maker’s size table. A tire is listed only with a source.

The math says 32.99″. 22 tires from 5 makers measure 32.90″–33.40″. Tallest here: Mickey Thompson Baja Boss A/T (all-terrain), 33.40″. Check the maker’s number before you buy for a tight fit.

Published dimensions for 275/60R20
TireTypeDiameterWidthRims, inWeightTreadMax load
Mickey Thompson Baja Legend EXPmickeythompsontires.com · Oct 15, 2026LT · E 123Q32.90″10.90″7.5–9.559.0 lb18.5/32″3,415 lb @ 80 psi
Nitto Recon Grappler A/Tnittotire.com · Oct 15, 2026LT · E 123/120S32.99″10.98″8.0–9.555.0 lb15.9/32″3,415 lb @ 80 psi
Firestone Destination X/Tfirestonetire.com · Oct 15, 2026LT · E 123R33.00″—7.5–9.551.9 lb16.0/32″—
Kumho Road Venture AT52kumhotireusa.com · Oct 15, 2026LT · D 119/116S33.00″11.00″8.0–9.553.1 lb16.0/32″3,000 lb @ 65 psi
Toyo Open Country A/T IIItoyotires.com · Oct 15, 2026LT · E 123/120T33.00″11.00″8.0–9.555.0 lb16.4/32″3,415 lb @ 80 psi
Toyo Open Country H/T IItoyotires.com · Oct 15, 2026LT · E 123/120R33.00″11.00″7.5–9.555.0 lb14.4/32″3,415 lb @ 80 psi
Nitto Dura Grapplernittotire.com · Oct 15, 2026LT · E 123/120R33.03″10.90″8.0–9.556.5 lb16.0/32″3,415 lb @ 80 psi
Nitto Ridge Grapplernittotire.com · Oct 15, 2026LT · E 123/120Q33.23″10.98″8.0–9.559.1 lb16.4/32″3,415 lb @ 80 psi
Mickey Thompson Baja Boss A/Tmickeythompsontires.com · Oct 15, 2026LT · E 123Q33.40″10.80″7.5–9.564.0 lb18.5/32″3,415 lb @ 80 psi
Nitto Ridge Grapplernittotire.com · Oct 15, 2026XL 116T32.99″10.98″7.5–9.547.2 lb13.5/32″2,756 lb @ 50 psi

§ 1

Size differences at a glance

By the formula 275/55R20 is 31.9 in (811 mm) overall and 275/60R20 is 33.0 in (838 mm). The change is +1.08 in or +3.4%, which is outside the ±3% shop guideline.

Section width is nominally unchanged at 10.8 in (275 mm). Sidewall height increases from 6.0 in (151 mm) to 6.5 in (165 mm). Revs per mile fall from 632 to 611 and axle clearance increases by 0.54 in (14 mm).

  • Diameter: 31.9 in → 33.0 in (+3.4%).
  • Section width: 10.8 in → 10.8 in (no change).
  • Sidewall: 6.0 in → 6.5 in; revs/mi 632 → 611.

§ 2

Speedometer, odometer, rpm

The speedometer and odometer read low after the change. True speed = indicated × 1.0339, so indicated 60 mph is 62.0 mph true and indicated 100 km/h is 103.4 km/h true; the odometer is off by +3.4%.

Engine speed falls for the same indicated speed. At 65 mph in 1.00 gear with a 3.73 axle ratio the engine drops from 2,554 rpm on 275/55R20 to 2,470 rpm on 275/60R20 (−3.3%). Restoring the original rpm by axle ratio requires 3.86, by the formula only. Use a speedometer calculator or gear-ratio calculator for other values.

§ 3

What makers publish

Makers list 23 tires in 275/55R20 and 22 tires in 275/60R20 across Nitto, Firestone, Kumho, Toyo and Mickey Thompson. Published overall diameters for 275/55R20 run 31.89–32.3 in against 31.91 in by the formula; 275/60R20 runs 32.9–33.4 in against 32.99 in by the formula.

Examples: Nitto lists LT275/55R20 at 31.89 in and LT275/60R20 at 32.99 in. Toyo lists Open Country A/T III at 31.9 in (275/55R20, 651 revs/mi) and 33 in (275/60R20, 630 revs/mi). Makers publish approved rim widths and load ranges with each listing.

  • Counts: 23 (275/55R20) and 22 (275/60R20).
  • Published diameters: 275/55R20 31.89–32.3 in; 275/60R20 32.9–33.4 in.

§ 4

Trade-offs by situation

A taller 275/60R20 increases axle ground clearance (+0.54 in) and lowers revs/mi and rpm. That changes acceleration feel, gearing effects and true speed versus indicated speed.

Widths are nominally the same. Both sizes appear in SL, XL, D and E load ranges; check the tire sidewall for the maker’s load rating and the driver’s door jamb placard for vehicle load information (49 CFR 571.139; 49 CFR 571.110). The ±3% window is a tire-shop rule of thumb, not a law.

  • Taller: more clearance, lower revs/mi and rpm, higher true speed.
  • Both sizes: same nominal width; multiple load ranges available; verify sidewall and placard.

Table 4

Sizes within 3% of 275/60R20

Same rim or ±1″, diameter within 3%. A shop rule of thumb, not a law.

Sizes within 3% of 275/60R20
SizeDiameterWidthvs 275/60R20At 60 mphClearance
33x11.50R2033.00″11.5″0.0%60.00.00″
33x12.50R2033.00″12.5″0.0%60.00.00″
295/55R2032.78″11.6″−0.7%59.6−0.11″
305/55R2033.21″12.0″+0.7%60.4+0.11″
265/60R2032.52″10.4″−1.4%59.1−0.24″
285/60R2033.46″11.2″+1.4%60.9+0.24″
285/55R2032.34″11.2″−2.0%58.8−0.32″
295/60R2033.94″11.6″+2.9%61.7+0.47″
305/50R2032.01″12.0″−3.0%58.2−0.49″

Q&A

Common questions

Will my speedometer read wrong with 275/60R20?

Yes. True speed = indicated × 1.0339; indicated 60 mph is 62.0 mph true and odometer distance is +3.4% off.

How much taller is 275/60R20 than 275/55R20?

By the formula 275/60R20 is 33.0 in (838 mm) versus 31.9 in (811 mm) for 275/55R20, a +1.08 in or +3.4% increase.

Do both sizes offer the same load ranges?

Yes. Maker tables show SL, XL, D and E across both sizes; the tire sidewall carries the maximum load rating and, for LT tires, the load range letter (49 CFR 571.139).

Can I restore original rpm after switching?

By the formula an axle ratio of 3.86 restores the 275/55R20 engine speed when running 275/60R20; this is a calculation only.

Notes

Method and sources

Each number and rule comes from a source with the date it was checked.

  1. Sidewall = width × aspect ratio ÷ 100
  2. Diameter = rim × 25.4 + 2 × sidewall (mm)
  3. Revs per mile = 63,360 ÷ (π × diameter, in)
  4. True speed = dial × new diameter ÷ old diameter
  5. Clearance change = half the diameter change

Numbers are nominal: the tire unloaded, on its measuring rim. Revs per mile published by makers run higher than the formula. “Within 3%” is a rule of thumb tire shops use, not a law. Tire pressure: the placard on your door jamb.

  1. Nitto: size table (nittotire.com)checked Oct 15, 2026
  2. Firestone: size table (firestonetire.com)checked Oct 15, 2026
  3. Kumho: size table (kumhotireusa.com)checked Oct 15, 2026
  4. Toyo: size table (toyotires.com)checked Oct 15, 2026
  5. Mickey Thompson: size table (mickeythompsontires.com)checked Oct 15, 2026
  6. Mickey Thompson: size table (mickeythompsontires.com)checked Oct 15, 2026
  7. 49 CFR 571.139 (FMVSS No. 139), S5.5(d)ecfr.gov · checked Oct 15, 2026
  8. 49 CFR 571.110 (FMVSS No. 110), S4.3ecfr.gov · checked Oct 15, 2026

Related

Calculators and size classes

33″22 metric and 11 flotation sizes measure 32.5–33.5″ by the formula305/70R16 · 285/75R16 · 295/75R16 · 305/65R17 · 285/70R1735″15 metric and 16 flotation sizes measure 34.5–35.5″ by the formula315/75R16 · 325/65R18 · 305/70R18 · 285/75R18 · 285/65R2037″3 metric and 13 flotation sizes measure 36.5–37.5″ by the formula385/70R16 · 315/80R17 · 375/45R24