Sheet TS-C02Rev. Oct 15, 2026United States · Canada

Data sheet TS-C02 · Comparison

275/60R20 vs 275/65R20

275/65R20 is about 1.08 in taller than 275/60R20 (34.1 vs 33.0 in), a +3.3% overall-diameter change by the formula.

Input

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

Fig. 1 — Cross-section, size 2

D34.1″B7.0″C20″A10.8″
275/65R20: A section width, B sidewall, C rim, D overall diameter. Nominal, on the measuring rim.

Table 1 — Data

275/65R20 is 34.07″ tall, +3.28% against 275/60R20. At 60 mph on the dial you drive 62.0 mph.

275/60R20 vs 275/65R20
Item275/60R20275/65R20Change
Overall diameter32.99″34.07″+3.28%
Section width10.83″10.83″0.00″
Sidewall6.50″7.04″+0.54″
Rim20″20″same
Revs per mile611592−19
Dial 60 mph =60.062.0+3.3%
Axle height16.50″17.04″+0.54″

+3.28% — 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 275/65R20 ↓

Fig. 2

Side view and width, to scale

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

33.0″34.1″+0.54″

275/60R20275/65R20

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 mph72.3 mph+2.3
80 mph82.6 mph+2.6

Engine RPM at the same road speed: −3.2%. Gear ratio calculator

Table 3

Published dimensions

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

The math says 34.07″. 22 tires from 5 makers measure 34.05″–34.70″. Tallest here: Mickey Thompson Baja Legend EXP (all-terrain), 34.70″. Check the maker’s number before you buy for a tight fit.

Published dimensions for 275/65R20
TireTypeDiameterWidthRims, inWeightTreadMax load
Nitto Dura Grapplernittotire.com · Oct 15, 2026LT · E 126/123R34.05″10.90″8.0–9.560.8 lb16.0/32″3,750 lb @ 80 psi
Firestone Winterforce LTfirestonetire.com · Oct 15, 2026LT · E 126R34.09″—7.5–9.557.3 lb18.0/32″—
Nitto Ridge Grapplernittotire.com · Oct 15, 2026LT · E 126/123Q34.09″10.98″8.0–9.560.9 lb16.4/32″3,750 lb @ 80 psi
Nitto Recon Grappler A/Tnittotire.com · Oct 15, 2026LT · E 126/123S34.09″10.98″8.0–9.558.6 lb15.9/32″3,750 lb @ 80 psi
Firestone Destination X/Tfirestonetire.com · Oct 15, 2026LT · E 126S34.10″—7.5–9.552.6 lb16.0/32″—
Firestone Transforce HT3firestonetire.com · Oct 15, 2026LT · E 126S34.10″—7.5–9.550.3 lb15.0/32″—
Firestone Transforce AT2firestonetire.com · Oct 15, 2026LT · E 126R34.10″—7.5–9.551.2 lb16.0/32″—
Kumho Road Venture AT52kumhotireusa.com · Oct 15, 2026LT · E 126/123S34.10″11.00″8.0–9.555.4 lb16.0/32″3,750 lb @ 80 psi
Kumho Road Venture RTkumhotireusa.com · Oct 15, 2026LT · E 126/123R34.10″11.00″8.0–9.562.7 lb17.3/32″3,750 lb @ 80 psi
Toyo Open Country A/T IIItoyotires.com · Oct 15, 2026LT · E 126/123S34.10″11.00″8.0–9.555.0 lb16.4/32″3,750 lb @ 80 psi

§ 1

How they differ

By the formula 275/60R20 measures 33.0 in (838 mm) overall and 275/65R20 measures 34.1 in (866 mm). The difference is +1.08 in (+3.3%).

Section width is essentially the same by the formula: 10.8 in (275 mm). Sidewall rises from 6.5 in (165 mm) to 7.0 in (179 mm). Revolutions per mile fall from 611 to 592 and axle clearance increases about 0.54 in (14 mm) by the formula.

§ 2

Speedometer and rpm

The speedometer and odometer read low after the change. True speed = indicated × 1.0328, so an indicated 60 mph is about 62.0 mph true and an indicated 30 mph is about 31.0 mph true; indicated 100 km/h reads about 103.3 km/h true and the odometer is off by +3.3%.

Engine speed at 65 mph in 1.00 gear with a 3.73 axle ratio falls from 2,470 rpm on 275/60R20 to 2,392 rpm on 275/65R20 (−3.2%). Restoring the original engine speed on 275/65R20 requires an axle ratio of about 3.85 by the formula.

§ 3

What makers publish

Makers' tables list 22 tires in each size across five brands. For 275/60R20 published diameters run about 32.9–33.4 in versus 32.99 in by the formula; for 275/65R20 published diameters run about 34.05–34.7 in versus 34.07 in by the formula.

Examples: Mickey Thompson lists LT275/60R20 at 32.9 in and LT275/65R20 at 34.5 in. Toyo lists the Open Country A/T III at 33 in in 275/60R20 (630 revs/mi) and 34.1 in in 275/65R20 (609 revs/mi). Makers must publish rims that may be used with each tire (49 CFR 571.139). See the detailed maker tables on the size pages: 275/60R20 and 275/65R20.

§ 4

Trade-offs by situation

A taller 275/65R20 raises axle height and reduces revs per mile and engine rpm. Expect the speedometer and odometer to read about 3.3% low and note that many 275/65R20 listings show higher weights and different tread depths or load capacities by model.

The ±3% overall-diameter window shops use is a rule of thumb and 275/65R20 sits outside that window at +3.3%. Check the tire sidewall for the maximum load rating and load range letter (49 CFR 571.139) and the tire and loading placard on the driver's door jamb for vehicle limits (49 CFR 571.110).

  • Axle clearance: +0.54 in (14 mm) by the formula.
  • Revs per mile: 611 → 592 (fewer revs).
  • Speedometer/odometer error: +3.3% (true = indicated × 1.0328).
  • Load ranges in maker tables: 275/60R20 lists SL, XL, D, E; 275/65R20 lists SL, E.

Table 4

Sizes within 3% of 275/65R20

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

Sizes within 3% of 275/65R20
SizeDiameterWidthvs 275/65R20At 60 mphClearance
34x11.50R2034.00″11.5″−0.2%59.9−0.04″
295/60R2033.94″11.6″−0.4%59.8−0.07″
285/65R2034.59″11.2″+1.5%60.9+0.26″
285/60R2033.46″11.2″−1.8%58.9−0.31″
315/60R2034.88″12.4″+2.4%61.4+0.40″
305/55R2033.21″12.0″−2.5%58.5−0.43″
35x11.50R2035.00″11.5″+2.7%61.6+0.46″
35x12.50R2035.00″12.5″+2.7%61.6+0.46″
35x13.50R2035.00″13.5″+2.7%61.6+0.46″
35x15.50R2035.00″15.5″+2.7%61.6+0.46″

Q&A

Common questions

Will a 275/65R20 change my speedometer reading?

Yes. True speed is about indicated × 1.0328, so an indicated 60 mph reads about 62.0 mph true and the odometer is off by +3.3%.

How much taller is 275/65R20 than 275/60R20?

By the formula it is 34.1 in versus 33.0 in, a difference of +1.08 in or +3.3% (866 vs 838 mm).

Do makers publish both sizes?

Yes. Makers' tables list 22 tires in each size across five brands; published diameters and weights vary by model—see the size pages for full tables.

Where is the load range shown on the tire?

The tire sidewall shows the maximum load rating and, for LT tires, the load range letter as required by 49 CFR 571.139.

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. Mickey Thompson: size table (mickeythompsontires.com)checked Oct 15, 2026
  2. Nitto: size table (nittotire.com)checked Oct 15, 2026
  3. Firestone: size table (firestonetire.com)checked Oct 15, 2026
  4. Kumho: size table (kumhotireusa.com)checked Oct 15, 2026
  5. Toyo: size table (toyotires.com)checked Oct 15, 2026
  6. Nitto: size table (nittotire.com)checked Oct 15, 2026
  7. Firestone: size table (firestonetire.com)checked Oct 15, 2026
  8. Mickey Thompson: size table (mickeythompsontires.com)checked Oct 15, 2026
  9. 49 CFR 571.139 (FMVSS No. 139), S5.5(d)ecfr.gov · checked Oct 15, 2026
  10. 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