The Nitto NT420V in size LT305/55R20 is a performance street radial tire with service description 125/122S. The NT420V is Nitto’s street-oriented tire for light trucks and SUVs.
Size and wheel specifications
- Tire size: LT305/55R20
- Manufacturer stock number: 206660
- Wheel diameter: 20 in
- Nominal section width: 305 mm
- Load index / speed rating: 125/122S
- Load designation: Load Range F (12-ply rating)
- Approved rim-width range: 9.0–11.0 in
- Measuring rim width: 9.5 in
- Manufacturer-listed overall diameter: 33.23 in
- Manufacturer-listed overall width: 12.44 in
- Tread depth: 14.2/32 in
- Maximum load / inflation rating (single-tire application): 3,640 lb at 80 psi
Nitto lists this exact stock number at 33.23 inches overall diameter and 12.44 inches overall width on the 9.5-inch measuring rim. The measuring rim is the reference for those published dimensions; the approved rim-width range is 9.0–11.0 inches.
The 125/122 load index lists 125 for single-tire use and 122 for dual-tire use. These ratings apply to different installation arrangements. The maximum-load figure above is the single-tire rating; do not use it as a dual-installation capacity.
Before ordering
Compare the complete size, load index and speed rating with your vehicle’s approved requirements. Confirm wheel width, wheel load capacity and clearance as well as diameter. A tire’s dimensions do not establish an OEM vehicle application. If changing tire size or type, have the combination and operating pressure checked by a qualified tire professional.
Questions about LT305/55R20
What do the numbers in LT305/55R20 mean?
The size uses a nominal 305 mm section width and an aspect ratio of 55; the sidewall height is expressed as a percentage of that nominal width. R denotes radial construction and 20 is the wheel diameter in inches. Nitto lists this exact tire at 33.23 inches overall diameter and 12.44 inches overall width on the 9.5-inch measuring rim. LT identifies the light-truck size designation.
What wheel width is approved for this LT305/55R20 tire?
Nitto lists 9.0–11.0 inches as the approved rim-width range for stock number 206660. Its 9.5-inch measuring rim is the reference for the published dimensions, not the only approved width. The wheel must also have the correct 20-inch diameter and be suitable for the vehicle and required load.
Does Load Range F mean this tire contains 12 physical plies?
No. Load Range F corresponds to a 12-ply rating, a load/strength classification rather than a count of physical cord layers. This tire’s service description is 125/122S. The load index is 125 in a single-tire application and 122 in a dual-tire application; S is the speed symbol.
Is 80 psi the pressure I should run in this tire?
No. The listed 3,640 lb at 80 psi is Nitto’s maximum load/inflation rating for a single-tire application. It is not a recommended pressure for every vehicle. Follow the applicable vehicle and tire guidance, and have the operating pressure confirmed when changing tire size, type or load requirements.
Will this LT305/55R20 tire fit any vehicle with 20-inch wheels?
No. A matching 20-inch wheel diameter is only one requirement. Check the approved 9.0–11.0-inch rim-width range, complete 125/122S service description, wheel load capacity and vehicle clearance. The published 33.23-inch diameter is useful for comparison, but does not prove vehicle fitment or that a lift or modification is unnecessary.
