For every 1" increase in tire diameter beyond stock, you lose ~3% of your effective gear ratio. Regearing is not optional once you go past 33" tires — it's a matter of when.
**Quick tire-to-gear guide (early Bronco, stock transfer case):**
| Tire Size | Minimum Ratio | Recommended |
|-----------|--------------|-------------|
| 31" | 3.73 | 3.73 or 4.09 |
| 33" | 4.09 | 4.09 or 4.56 |
| 35" | 4.56 | 4.56 or 4.88 |
| 37" | 4.88 | 4.88 or 5.13 |
The early Bronco's Dana 20 transfer case has a 2.03:1 low range — modest by modern standards. Steeper axle gearing compensates for the weak low range and larger tires.
**Matching front and rear:** Both axles must have identical ratios. The Dana 44 front and rear use different-diameter ring gears (both 8.5 in for the early Bronco) but the same ratio options are available. Yukon, G2, and Nitro all make Dana 44 sets.
**Professional setup vs. DIY:** Ring and pinion setup requires a bearing press, dial indicator, and pattern marking compound. Backlash must be set to spec (0.006"–0.010" for Dana 44). The cost of a bad setup (spun bearings, broken ring gear) exceeds the cost of professional labor. Labor typically runs $300–450 per axle at a driveline shop.
| Part | Vendor | Est. price |
|---|---|---|
| Yukon 4.56 ring and pinion set (Dana 44) | Yukon Gear | ~$290 |
| Yukon 4.88 ring and pinion set (Dana 44) | Yukon Gear | ~$290 |
| Dana 44 master install kit | Yukon Gear | ~$95 |
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.