The Nitto Ridge Grappler in size LT285/55R20 is a hybrid-terrain radial tire with a 122/119Q service description. The Ridge Grappler is Nitto’s hybrid-terrain option, positioned between an all-terrain and a mud-terrain tire.
Size and wheel specifications
- Tire size: LT285/55R20
- Manufacturer stock number: 217340
- Wheel diameter: 20 in
- Nominal section width: 285 mm
- Load index / speed rating: 122/119Q
- Load designation: Load Range E (10-ply rating)
- Approved rim-width range: 8.5–10.0 in
- Measuring rim width: 9.0 in
- Manufacturer-listed overall diameter: 32.60 in
- Manufacturer-listed overall width: 11.69 in
- Tread depth: 16.4/32 in
- Maximum load / inflation rating (single-tire application): 3,305 lb at 80 psi
Nitto lists this exact stock number at 32.60 inches overall diameter and 11.69 inches overall width on the 9.0-inch measuring rim. The measuring rim is the reference for those published dimensions; the approved rim-width range is 8.5–10.0 inches.
The 122/119 load index lists 122 for single-tire use and 119 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 LT285/55R20
What do the numbers in LT285/55R20 mean?
The size uses a nominal 285 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 32.60 inches overall diameter and 11.69 inches overall width on the 9.0-inch measuring rim. LT identifies the light-truck size designation.
What wheel width is approved for this LT285/55R20 tire?
Nitto lists 8.5–10.0 inches as the approved rim-width range for stock number 217340. Its 9.0-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 E mean this tire contains 10 physical plies?
No. Load Range E corresponds to a 10-ply rating, a load/strength classification rather than a count of physical cord layers. This tire’s service description is 122/119Q. The load index is 122 in a single-tire application and 119 in a dual-tire application; Q is the speed symbol.
Is 80 psi the pressure I should run in this tire?
No. The listed 3,305 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 LT285/55R20 tire fit any vehicle with 20-inch wheels?
No. A matching 20-inch wheel diameter is only one requirement. Check the approved 8.5–10.0-inch rim-width range, complete 122/119Q service description, wheel load capacity and vehicle clearance. The published 32.60-inch diameter is useful for comparison, but does not prove vehicle fitment or that a lift or modification is unnecessary.
