The short answer for an early Bronco: 33s are the sweet spot. A 33x12.50R15 clears with a 2.5–3" lift and modest trimming, fits the stock Dana 44s without re-gearing being mandatory, and keeps the truck driving like a truck instead of a tractor. 35s look great and crawl better but cost you gearing, steering effort, and fender real estate. 31s bolt under a near-stock truck. Pick the tire to match the lift and the gears you're willing to run, not the other way around.
The early Bronco is small and light, which works in your favor — it doesn't take a tall lift to clear a big tire the way a full-size truck does. But the short wheelbase and the stock 3.50 or 4.11 gearing mean a tall tire changes the driving character fast. Every inch of tire diameter is a step away from the gearing the engine was tuned for.
Know three things before you buy: your lift height, your wheel backspacing, and your axle gear ratio. Tire fitment is the interaction of all three. A 33 that clears on a 3.75" backspacing wheel will rub on a 4.5" wheel because it sits further inboard into the radius arm and frame. See the companion guide on backspacing — it matters as much as lift for fitment.
Match the tire to the build:
**31x10.50R15** fits a stock-height or 1–2" lifted early Bronco with stock backspacing, with little or no trimming. This is the choice for a stock restoration or a mild trail truck that still has to drive nicely on the highway with stock 3.50 gears. Minimal speedometer error, no steering penalty.
**33x12.50R15** is the most popular early Bronco size and the one most builds settle on. It needs a 2.5–3" suspension lift, a wheel in the 3.75–4.0" backspacing range, and usually some fender lip trimming or a cut-and-fold at full stuff. With 3.50 gears a 33 is livable but lazy; with 4.11s it's well-matched; with 4.56s it's strong. This size balances clearance, ride, and street manners better than anything else on these trucks.
**35x12.50R15** needs a 3.5–4" lift (or a 2.5–3" lift plus a body lift and aggressive trimming), and re-gearing is effectively mandatory — plan on 4.56 or 4.88 gears to keep the small-block out of the doldrums. Steering effort climbs noticeably; a power steering conversion or a hydraulic assist is worth budgeting. This is rock-crawler territory.
For each size, measure before you commit: stuff the suspension to full bump with the tire mounted and the wheel at full lock both directions, and look for contact at the rear of the front fender, the radius arm, and the frame. Trimming the fender lip and a tucked inner fender buys the clearance most builds need.
The biggest mistake is buying tall tires and skipping the gear change. A 35 on 3.50 gears makes the truck feel gutless, hot, and slow, and it hammers the automatic transmission's torque converter. Tire and gear decisions are one decision. Read the gear ratio guide alongside this one.
Watch wheel backspacing — a deep-backspaced wheel tucks the tire into the radius arm and frame and causes inner rub that no amount of fender trimming fixes. Width also matters: a 12.50 section on a narrow rim balloons the sidewall outward and worsens fender contact.
Don't forget the speedometer. Going from 31s to 33s or 35s makes the speedometer read slow; a recalibrated gear or an electronic correction keeps you legal and keeps the odometer honest.
A set of five 31s runs roughly $1,000–1,250; 33s run $1,300–1,700; 35s run $1,600–2,000, with mud-terrains at the top of each range. Add gearing ($1,200–1,800 installed for both axles) if you go to 35s. You probably don't need 35s for the vast majority of trail driving — a 33 clears the same obstacles with less penalty everywhere else, and most early Broncos look and wheel their best on 33s.
| Part | Vendor | Est. price |
|---|---|---|
| 31x10.50R15 all-terrain (stock-ish fit) | BFG / Cooper / Falken | ~$220 |
| 33x12.50R15 all-terrain (most popular EB size) | BFG / Cooper / Toyo | ~$270 |
| 35x12.50R15 mud-terrain | BFG / Nitto | ~$330 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.