Best For
- Trucks, SUVs, and builds that need clearance, load capacity, or trail capability
- Towing, payload, gravel, trails, or overland use with stronger LT options
- Daily-driven trucks that still see mixed on/off-road miles
Light Truck
305/55R20 Tire Size
Overall Diameter
33.21in
Affects ride height, gearing, and speedometer accuracy.
Section Width
12.01in
Affects traction footprint and steering effort.
Sidewall Height
6.60in
Influences ride comfort and off-road compliance.
Circumference
104.33in
Determines distance traveled per wheel revolution.
Revs Per Mile
607
Used for speedometer and gearing calculations.
Wheel Diameter
20in
Determines wheel compatibility and fitment.
305/55R20 is a truck/SUV-oriented size that pairs 305 mm width with a 55% sidewall on a 20-inch wheel. At roughly 33.2" overall (~6.6" sidewall), it is typically chosen for clearance, load capacity, and mixed on/off-road use rather than max fuel economy. Products indexed for this size include all-terrain and touring options. Expect heavier steering and a possible speedometer change vs shorter factory sizes — verify clearance and load range before upgrading.
- Strong fit for trucks/SUVs, towing, gravel, trails, or overland use depending on tread choice.
- Indexed products include 4 brands and 17 full-spec rows.
- Tradeoffs may include ride comfort, steering weight, clearance, speedometer change, or fuel economy depending on the jump from stock.
At a Glance
Nominal dimensions calculated from the 305/55R20 size code (305/55R20). Load range and speed rating come from indexed manufacturer products when available.
Rim Diameter Calculated
20"
Section Width Calculated
305 mm
Aspect Ratio Calculated
55%
Load Range Manufacturer
E, F
Speed Rating Manufacturer
Q, R, S
Construction Standard
Radial
Applicable Tire Categories
Based on this size’s editorial category and exact-size product metadata. A size may support several uses without every product in the size belonging to every category.
Consider Another Size If
- Fuel economy, light steering, and factory-like ride comfort matter more than clearance
- You prefer a smaller, more stock look or quieter highway manners
- You need a dedicated extreme off-road size beyond mixed daily use
Real-World Impact
- More ground clearance and a taller off-road footprint
- Stronger load-carrying options for towing and payload
- Heavier steering feel and a bit more rotational mass
- Usually a small hit to fuel economy vs smaller highway sizes
Verified Vehicle Examples
Documented OE or commonly associated platforms for 305/55R20.
-
Ford
F-150
Raptor
2017–2020
-
Ram
1500
Rebel
2019–2024
-
Chevrolet
Silverado 1500
Trail Boss
2019–2024
-
Toyota
Tundra
TRD Pro
2015–2021
-
GMC
Sierra 1500
AT4
2019–2024
Documented fitment mappings for research. Vehicle clearance depends on trim, wheel offset, suspension height, and tire model — confirm fitment before buying.
Real Tires Available in This Size
Indexed manufacturer models confirmed in exact size 305/55R20
Manufacturer-provided product/spec data from Michelin, Goodyear, BFGoodrich, Toyo, and Falken where available.
All-Terrain
All-Terrain T/A KO3
305/55R20 · 125S · Load Range F
All-Terrain
Open Country A/T III
305/55R20 · 116S · Load Range SL
All-Terrain
Rubitrek A/T
305/55R20 · 121/118S · Load Range E
All-Terrain
Wildpeak A/T4W
305/55R20 · 116T · Load Range SL
All-Terrain
Discoverer Rugged Trek LT
305/55R20 · 125Q · Load Range F
All-Terrain
Discoverer Stt Pro
305/55R20 · 125Q · Load Range F
Best Options by Use Case
All-Terrain
Best first stop for mixed daily driving, gravel, trails, and overland use.
Top pick
Goodyear Discoverer® Rugged Trek® LT
Other options
- Goodyear Discoverer® Stt Pro™
- Goodyear Wrangler Duratrac® RT-LT
Product Spec Comparison
Compare tread depth, weight, max load, pressure, and revs per mile for full-spec 305/55R20 products.
FAQ
Is 305/55R20 good for off-road and truck use?
305/55R20 is a capable off-road and truck use size when clearance, load capacity, or mixed trail use matter. At roughly 33.21" overall (~6.60" sidewall on a 20-inch wheel), it sits in the truck/SUV capability band rather than a pure fuel-economy size. Pair it with the right tread and load range for your mileage mix.
What vehicles use 305/55R20 tires?
305/55R20 is commonly seen on or upgraded to by owners of trucks, SUVs, and crossover platforms that can clear this diameter. Exact factory fitment depends on trim, wheel offset, and suspension height — confirm clearance and load requirements before treating it as a direct replacement.
What load ranges are available?
Indexed products for 305/55R20 include load ranges such as E, F, and SL, depending on brand and model. Load capacity still comes from the load index and inflation table on the specific tire — not the size code alone. Match the load range to your GVWR and intended payload or towing use.
Which brands make 305/55R20 tires?
Indexed master-database coverage for 305/55R20 includes BFGoodrich, Toyo, Falken, and Goodyear. Availability still varies by load range, tread type, and season — check the product cards and full-spec table on this page for models currently listed.
How does 305/55R20 compare to 285/65R20?
305/55R20 measures about 33.21" overall versus 34.59" for 285/65R20 (-1.4" / -4.0%). The shorter size usually trims rotational mass and can raise the speedometer reading relative to actual speed, with less ground clearance. Always check fender clearance and load rating before switching.
What is the load capacity of 305/55R20?
Load capacity depends on the exact tire, load index, and inflation pressure — not the size code alone. Check the manufacturer load table and your vehicle placard when setting pressure or carrying heavy loads. If multiple load ranges exist for this size, choose the one that meets or exceeds the placard requirement.
Formula & Methodology
Every dimension on this site is computed in code from the tire size label — we do not scrape or hand-copy manufacturer spec sheets for overall diameter or circumference.
- Parse the size label. Metric sizes (e.g. 275/70R18, LT265/75R16) and flotation sizes (e.g. 33x12.50R15) are parsed into section width, aspect ratio, construction type, and bead-seat wheel diameter.
- Derive nominal dimensions. Sidewall height = section width × aspect ratio ÷ 100. Overall diameter = wheel diameter + 2 × sidewall height. Rolling circumference = π × overall diameter. Revs per mile = 63,360 ÷ circumference (inches per mile). Revs per km uses the same circumference converted to millimetres.
- Compare two sizes. Diameter, width, sidewall, and circumference deltas are signed differences between parsed specs. Speedometer error assumes the cluster is calibrated to the reference tire: true speed = indicated speed × (new diameter ÷ reference diameter). Static ground clearance change uses half the overall-diameter delta at each axle.
Rim diameter shown on this page is always 20" — the bead-seat diameter encoded in 305/55R20.
Safety & Fitment Limitations
- Calculated dimensions are nominal planning baselines from the size code — mounted tires can differ with tread depth, inflation, rim width, and production tolerance.
- Always confirm 305/55R20 against the door placard or owner’s manual, including load index, load range, and speed rating for your vehicle.
- Changing diameter affects speedometer accuracy, gearing feel, ABS/traction calibration, and clearance at fenders, control arms, and the spare well.
- Vehicle examples and product cards are not a guarantee of fitment. Verify wheel diameter (20"), offset, and suspension setup before buying.
Sources & Review
Dimensions are calculated from the tire size label; product rows and fitment mappings come from documented manufacturer and OE sources where available.
- Curated tire-size dataset. Production tire labels, vehicle categories, and optional load/speed ratings maintained in our internal catalog. Only field-valid sizes that round-trip through the parser are published.
- ISO / ETRTO service-description tables. Load index → maximum load (kg) and speed rating symbol → maximum sustained speed (km/h) mappings embedded in our rating resolver, aligned with widely published ETRTO reference values.
- Nominal tire geometry formulas. Overall diameter, sidewall, circumference, and revolutions per mile are calculated from the size code using standard metric and flotation geometric relationships — the same relationships used across the tire industry for nominal sizing.
- Documented OE fitment mappings. Vehicle make, model, trim, and year-range associations linked to specific tire sizes in our fitment data. These are representative applications for research — always confirm against your door placard.
Next step: compare 305/55R20 before changing tire sizes
Compare 305/55R20 against nearby sizes like 285/65R20, 275/70R18, 275/60R20 to check diameter change, speedometer impact, clearance, and fitment tradeoffs.