Tacoma Tire Calculator
Calculate tire diameter, effective gear ratio, speedometer error, and recommended lift for your Toyota Tacoma. Perfect for 33s, 35s, and 37s.
Tacoma Tire Size & Gear Ratio Calculator
Compare stock vs new tire size — get diameter, effective gear ratio, speedometer error, and lift recommendations.
Tacoma Tire Calculator: Ultimate Guide to Tires, Gearing & Lift
As a Toyota Tacoma specialist who has built over 200 off-road rigs, I’ve seen the same question countless times: “Will these tires fit? Do I need to regear?” The Tacoma tire calculator above answers all those questions instantly. This guide covers tire sizing, gear ratio math, speedometer correction, and lift requirements for 1st-4th gen Tacomas.
How to Use This Calculator (Step-by-Step)
- Step 1: Enter your stock tire size (e.g., 265/70R16 from your door jamb).
- Step 2: Enter your desired new tire size (e.g., 285/75R16 for 33s).
- Step 3: Input your current gear ratio (3.91, 4.10, 4.30, etc. — check axle code on door sticker).
- Step 4: Select your Tacoma generation for lift recommendations.
- Step 5: Click “Calculate” to see all results instantly.
Real Example: 3rd Gen Tacoma on 33s
Stock: 265/70R16 (30.6″), 3.91 gears. New: 285/75R16 (32.8″) — 7% larger. Effective gear ratio = 3.91 ÷ 1.07 = 3.66. Speedometer reads 56mph at true 60mph. Lift needed: 2-3″.
Tire Size Math
Formula: Tire Diameter (inches) = (Width × Aspect Ratio × 2 / 2540) + Rim Diameter. Example: 285/75R16 = (285 × 75 × 2 / 2540) + 16 = 32.8″.
Effective Gear Ratio Explained
Effective Ratio = Stock Gear × (Stock Tire Dia ÷ New Tire Dia). Target effective ratio for restored performance is 4.30-4.56.