CarSpecsHQ

345/30R19 vs 265/35R20

265/35R20 is a safe swap for 345/30R19 by the usual ±3% rule: the diameter differs by +0.57%.

19" → 20"
345/30R19 27.15" · 265/35R20 27.30" · drawn to scale

Side by side

345/30R19265/35R20Difference
Overall diameter27.15"27.30"+0.15" (+0.57%)
Section width345 mm265 mm-80 mm
Sidewall4.07"3.65"-0.42"
Rim19"20"+1"
Circumference85.3"85.8"+0.5"
Revs per mile743739-4
Ride height——+0.08"
Speedometer reads 60 mph60.060.3+0.3 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.3 mph

With 265/35R20 on a car calibrated for 345/30R19, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.6%.

Speedo showsActual speed
30 mph30.2 mph
45 mph45.3 mph
60 mph60.3 mph
70 mph70.4 mph
80 mph80.5 mph

Other sizes close to 345/30R19

Questions

Can I replace 345/30R19 with 265/35R20?

265/35R20 is a safe swap for 345/30R19 by the usual ±3% rule: the diameter differs by +0.57%.

What's the difference between 345/30R19 and 265/35R20?

265/35R20 is 0.15" taller and 80 mm narrower; the sidewall is -0.42". At an indicated 60 mph you'd actually be doing 60.3 mph.

Will 265/35R20 fit on 345/30R19 wheels?

No — 345/30R19 needs a 19" wheel and 265/35R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.