Truck Tire Size Calculator
Compare any truck tire size — lifted, semi, or commercial. Supports metric (295/75R22.5), numeric (11R22.5), and flotation (35×12.50R17). Includes gear ratio recalibration, speedometer correction, load capacity, and OEM spec charts.
Quick Answer
The most common semi truck tire size is 295/75R22.5 (Load Range G, 110 PSI, ~40.5″ OD), followed by 11R22.5 (~41.3″ OD). For lifted light trucks, 35×12.50R17 (equivalent to 315/70R17) is the most popular size — requiring a 3–4″ suspension lift and typically a gear ratio upgrade from 3.55 → ~4.10 to restore factory performance.
| Use Case | Tire Size | OD | Load Range | Note |
|---|---|---|---|---|
| Common semi steer/drive | 295/75R22.5 | ~40.5" | G (110 PSI) | Most common Class 8 tire — ~28% of new semis |
| Semi drive / legacy fleet | 11R22.5 | ~41.3" | G/H (110–120 PSI) | Legacy numeric — better heat on long-haul drives |
| 3–4" lifted truck (F-150) | 35×12.50R17 / 315/70R17 | 35.0" | E (80 PSI) | Most popular lifted light truck size |
| Stock heavy-duty pickup | LT275/65R20 | 34.2" | E (80 PSI) | Ram HD, Silverado HD factory spec |
| Medium-duty delivery truck | 225/70R19.5 | ~30.9" | G (110 PSI) | F-650/750, box truck, step-van |
Use the calculator below to compare any two sizes across all three formats, get gear ratio recalibration, and view full OEM specs. Size Diff tab handles the math — Lifted, Semi, Load, and Formats tabs provide reference data.
Truck Tire Size Difference CalculatorAll Formats
Quick presets — common truck size swaps
Truck Tire Outer Diameter & Dimension Reference
Pre-calculated outer diameter, section width, sidewall height, circumference, and revs/mile for the most commonly referenced truck tire sizes across all three formats. All values computed from standard ISO/TRA formulas.
| Tire Size | OD | Sec. Width | Sidewall | Circ. | Rev/Mile | Load Range | Common Use |
|---|---|---|---|---|---|---|---|
| 295/75R22.5 | 40.5" | 11.6" | 8.71" | 127.2" | 498 | G | Class 8 steer / drive / trailer |
| 285/75R24.5 | 42.5" | 11.2" | 8.27" | 133.5" | 475 | G | Newer Peterbilt/Kenworth steer |
| 11R22.5 | 41.3" | 10.8" | 10.12" | 129.7" | 488 | G/H | Class 8 legacy drive/trailer |
| 445/50R22.5 | 41.0" | 17.5" | 8.74" | 128.8" | 492 | L | Wide-base single — replaces dual pair |
| 225/70R19.5 | 30.9" | 8.9" | 6.19" | 97.0" | 653 | G | Medium-duty delivery / F-650 |
| LT275/65R20 | 34.2" | 10.8" | 7.01" | 107.4" | 590 | E | HD pickup — Ram/Silverado factory |
| 265/70R17 | 31.6" | 10.4" | 7.24" | 99.2" | 639 | E | 1/2–3/4 ton stock light truck |
| 35×12.50R17 | 35.0" | 12.5" | 8.5" | 109.9" | 577 | D/E | 3–4" lifted truck — most popular |
| 37×12.50R17 | 37.0" | 12.5" | 9.5" | 116.2" | 546 | D/E | 6" lifted truck / serious off-road |
| 315/70R17 | 34.4" | 12.4" | 8.63" | 108.0" | 587 | E | 35" metric equiv. — most lifted trucks |
OD values computed from nominal size codes. Actual manufactured dimensions vary ±1–2% by brand. Verify against vehicle door placard and owner's manual before purchasing.
How Truck Tire Sizes Are Calculated — All Three Formats
Metric Format (295/75R22.5)
Metric (295/75R22.5): Sidewall Height = (295 mm × 0.75) ÷ 25.4 = 8.72 in Outer Diameter = 22.5 + (2 × 8.72) = 39.9 in (~40.5 in with mfg tolerance) Circumference = π × 39.9 = 125.3 in Revs/Mile = 63,360 ÷ 125.3 = 505
Legacy Numeric Format (11R22.5)
Legacy Numeric (11R22.5): Sidewall Height = 11 in × 0.92 = 10.12 in (92% assumed AR) Outer Diameter = 22.5 + (2 × 10.12) = 42.74 in Circumference = π × 42.74 = 134.2 in Revs/Mile = 63,360 ÷ 134.2 = 472
Flotation / Inch Format (35×12.50R17) & Gear Ratio
Flotation (35×12.50R17): Outer Diameter = 35.0 in (stated directly) Circumference = π × 35.0 = 109.9 in Revs/Mile = 63,360 ÷ 109.9 = 577 Gear Ratio Recalibration: New Ratio = Stock Ratio × (New OD ÷ Stock OD) Example: 3.55 × (35.0 ÷ 31.6) = 3.55 × 1.108 = 3.93 → upgrade to 4.10
- Larger OD → lower effective gear ratio → slower acceleration, higher cruise RPM, stressed transmission. Re-gear if OD increases more than ~7%.
- Larger OD → speedometer reads low → you are going faster than displayed. Recalibrate via OBD-II tuner or dealer.
- Higher load index / load range → more weight capacity and higher recommended PSI. Never exceed load range rated for your axle GAWR.
How to Use This Truck Tire Size Calculator
- 1Enter your stock tire size: In the Size Diff tab, type your current tire size in any format — metric (295/75R22.5), numeric (11R22.5), or flotation (35×12.50R17). The calculator auto-detects the format.
- 2Enter your proposed new size: Type the new tire size you are considering in the New / Proposed field. Mix formats freely — compare a flotation size against a metric equivalent.
- 3Add your stock gear ratio (optional): Enter your current axle gear ratio (e.g. 3.55 or 3.73). The calculator will compute the recommended new ratio to maintain equivalent performance after the tire size change.
- 4Use a quick preset: Click any of the pre-loaded common truck swaps — F-150, Silverado, Ram, Tacoma, Tundra, and semi truck size changes — to populate fields instantly and calculate in one click.
- 5Read all results: Review the EV Safety badge, OD delta percentage, speedometer correction table (25–80 mph), gear ratio recommendation, and all dimensional metrics including sidewall height, circumference, and rev/mile.
- 6Check the specialized tabs: Use Lifted for lift-to-tire clearance charts and common truck OEM sizes. Use Semi/Commercial for the full 17-row OEM spec chart and the 295 vs. 11R comparison. Use Load/Ply to calculate weight capacity from any load index. Use Formats for flotation↔metric conversion and sidewall marking decoder.
Truck Tire Rules — What Every Owner Should Know
📐 Match OD on Tandem Axles
Mismatched outer diameters on a semi's tandem drive axles force one tire to drag and the other to lead. Keep OD within ±¼ inch on the same axle. Mix brands only after verifying identical OD.
⚙️ Re-Gear After Big Tire Upgrades
Any OD change over 7% on a light truck degrades acceleration, towing capacity, and transmission shift points. Use the Size Diff tab to calculate your required new ratio. Common upgrades: 3.73 → 4.56 for 35–37" tires on 1/2-ton trucks.
🏋️ Load Range Must Match GAWR
Your truck's door placard specifies minimum load index and load range per axle. Never downgrade — using Load Range E tires where G is specified creates a blowout risk at highway speeds when loaded near GVWR.
📏 Flotation vs. Metric Are Equivalent
35×12.50R17 and 315/70R17 are nearly identical in OD (~35\"). Use the Formats tab for the full conversion chart. When ordering tires, verify OD matches — different brands can vary ±0.5" even within the same nominal size.
🌡️ Cold PSI for Trucks
Always measure tire pressure when cold (truck parked 3+ hours). Truck tires heat up dramatically under load — a semi drive tire can rise 20–30 PSI from cold to running temperature. Never bleed hot tires to target pressure.
🔄 LT vs. P-Metric on HD Pickups
Always use LT-rated tires on 3/4-ton and 1-ton trucks towing or hauling near GVWR. P-metric tires at the same nominal size carry significantly less load. The Load Range E minimum (80 PSI) is the industry standard for F-250/F-350, Ram 2500/3500, and all GM 2500HD/3500HD trucks.