245/30R20 vs 305/30R19 tire size comparison
305/30R19 is 0.4 in (1.62%) taller than 245/30R20 and 2.4 in wider. They fit different wheels: 245/30R20 a 20-inch wheel and 305/30R19 a 19-inch wheel.
245/30R20 and 305/30R19 side by side
| Measurement | 245/30R20 | 305/30R19 | Difference | Difference % |
|---|---|---|---|---|
| Section width | 9.6 in (245 mm) | 12.0 in (305 mm) | +2.4 in (+60 mm) | +24.49% |
| Sidewall height | 2.9 in (74 mm) | 3.6 in (92 mm) | +0.7 in (+18 mm) | +24.49% |
| Wheel (rim) diameter | 20.0 in (508 mm) | 19.0 in (483 mm) | -1.0 in (-25 mm) | -5.00% |
| Overall diameter | 25.8 in (655 mm) | 26.2 in (666 mm) | +0.4 in (+11 mm) | +1.62% |
| Circumference | 81.0 in (2058 mm) | 82.3 in (2091 mm) | +1.3 in (+33 mm) | +1.62% |
| Revolutions per mile | 782 | 770 | -12 | -1.59% |
Differences are 305/30R19 minus 245/30R20; percentages are relative to 245/30R20. These are nominal design dimensions. Real tires vary by brand, tread depth, wheel width, load and pressure.
The overall diameter differs by 1.62%, which is within the common 3% rule of thumb.
The rule of thumb keeps a replacement size within about 3% of the original overall diameter. It covers diameter only. It is not a fit, load or safety check, because width, wheel diameter, load capacity and clearance matter too. Confirm any size change with your vehicle's owner's manual or a tire professional.
Speedometer difference
When the speedometer reads 60 mph on a vehicle built for 245/30R20, the actual speed on 305/30R19 is about 61.0 mph. When it reads 60 mph on a vehicle built for 305/30R19, the actual speed on 245/30R20 is about 59.0 mph. These figures assume the speedometer is accurate on the original size and use nominal dimensions, so treat them as estimates.
| Speedometer reads | Actual on 305/30R19 (built for 245/30R20) | Actual on 245/30R20 (built for 305/30R19) |
|---|---|---|
| 20 mph | 20.3 mph | 19.7 mph |
| 30 mph | 30.5 mph | 29.5 mph |
| 40 mph | 40.6 mph | 39.4 mph |
| 50 mph | 50.8 mph | 49.2 mph |
| 60 mph | 61.0 mph | 59.0 mph |
| 70 mph | 71.1 mph | 68.9 mph |
| 80 mph | 81.3 mph | 78.7 mph |
A common rule of thumb is to keep a replacement size within about 3% of the original overall diameter. Check the tire placard on the driver's door jamb and your owner's manual for the sizes your vehicle was built for. Confirm any size change with your vehicle's owner's manual or a tire professional.
Which vehicles use each size?
These vehicles list the size among their verified sizes, by trim. Open one to see all of its sizes.
245/30R20
305/30R19
Check it in the calculator
The calculator takes the same two sizes and shows the full comparison, or lets you swap either one for another size.
Open this comparison in the calculatorShop for 245/30R20 or 305/30R19 tires
Confirm the size on your tire sidewall or door placard first. These links open each store's own search; prices and stock are on their sites.
245/30R20
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Other comparisons with 245/30R20
Side-by-side dimensions and speedometer difference for sizes close to 245/30R20 in overall diameter.
- 245/30R20 vs 245/35R19-0.14% shorter than 245/30R20
- 225/50R17 vs 245/30R20+0.27% taller than 245/30R20
- 245/30R20 vs 245/40R18-0.27% shorter than 245/30R20
- 205/55R17 vs 245/30R20+0.35% taller than 245/30R20
- 205/60R16 vs 245/30R20-0.40% shorter than 245/30R20
Other comparisons with 305/30R19
Side-by-side dimensions and speedometer difference for sizes close to 305/30R19 in overall diameter.
- 195/60R17 vs 305/30R19+0.03% taller than 305/30R19
- 215/60R16 vs 305/30R19-0.18% shorter than 305/30R19
- 205/70R15 vs 305/30R19+0.36% taller than 305/30R19
- 215/55R17 vs 305/30R19+0.41% taller than 305/30R19
- 225/40R19 vs 305/30R19-0.45% shorter than 305/30R19
You might also need
- Digital tire pressure gauge (Amazon search, opens in a new tab)
Check your tire pressure against the number on your door placard.
- Portable tire inflator (Amazon search, opens in a new tab)
Top up a low tire at home without a trip to the gas station.
- Tire tread depth gauge (Amazon search, opens in a new tab)
Measure how much tread is left before you decide to replace.
- Lug wrench or torque wrench (Amazon search, opens in a new tab)
Useful for rotations and tire changes; follow the torque spec in your owner's manual.
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