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Ford Bronco / F-Series (classic) Regear Chart (1966-1996)
Factory transmissions, transfer cases and axle ratios for the Ford Bronco / F-Series (classic) — with the two tables every regear decision runs on: cruise RPM at 70 mph and crawl ratio, for every ratio you can actually buy. All data verified against manufacturer specs (sources at the bottom of the page).
Factory presets
| Trim / preset | Transmission | Transfer case | Axle | Factory tire | Crawl | RPM @ 70 |
|---|---|---|---|---|---|---|
| NP435 + NP205 + 3.50 (early Bronco / F-150) | NP435 4-speed manual (Ford wide-ratio) | NP205 part-time (gear drive) | 3.50 | 235/75R15 (28.9 in) | 45.8:1 | 2,850 |
| C6 + BW1356 + 3.50 (OBS F-150/Bronco) | C6 3-speed automatic | BW1356 part-time (chain) | 3.50 | 235/75R15 (29.0 in) | 23.2:1 | 2,840 |
| C6 + NP205 + 4.11 (F-250 / heavy Bronco combo) | C6 3-speed automatic | NP205 part-time (gear drive) | 4.11 | LT265/75R16 (31.7 in) | 19.8:1 | 3,051 |
Crawl and RPM computed from the factory ratios listed — load any preset into My Garage and the calculators use it everywhere.
Cruise RPM at 70 mph — NP435 4-speed manual (Ford wide-ratio), top gear 1.00
| Tire | 3.00 | 3.50 | 4.11 | 4.56 | 4.88 | 5.13 | 5.38 |
|---|---|---|---|---|---|---|---|
| 29 in | 2,434 | 2,840 | 3,335 | 3,700 | 3,959 | 4,162 | 4,365 |
| 32 in | 2,206 | 2,574 | 3,022 | 3,353 | 3,588 | 3,772 | 3,956 |
| 33 in | 2,139 | 2,496 | 2,930 | 3,251 | 3,480 | 3,658 | 3,836 |
| 35 in | 2,017 | 2,353 | 2,763 | 3,066 | 3,281 | 3,449 | 3,617 |
| 37 in | 1,908 | 2,226 | 2,614 | 2,900 | 3,103 | 3,262 | 3,421 |
Crawl ratio — first gear 6.68, by transfer case and axle
| Transfer case | 3.00 | 3.50 | 4.11 | 4.56 | 4.88 | 5.13 | 5.38 |
|---|---|---|---|---|---|---|---|
| NP205 part-time (gear drive) (1.96:1) | 39.3 | 45.8 | 53.8 | 59.7 | 63.9 | 67.2 | 70.4 |
| BW1345 part-time (chain) (2.72:1) | 54.5 | 63.6 | 74.7 | 82.9 | 88.7 | 93.2 | 97.8 |
| BW1356 part-time (chain) (2.69:1) | 53.9 | 62.9 | 73.9 | 81.9 | 87.7 | 92.2 | 96.7 |
| NP208 part-time (chain, 1980s Fords) (2.61:1) | 52.3 | 61.0 | 71.7 | 79.5 | 85.1 | 89.4 | 93.8 |
Axles under this platform
- Dana 44 (71-77 Bronco) / Dana 44 TTB (80+ F-150) Carrier break: 3.92 (3.73 & down use one carrier; 3.92 & up the other — confirmed by Yukon carrier listings). Non-Rubicon TJ rear is 30-spline; Rubicon TJ is 32-spline rear with air/electric locker variants by year. Practical ratios 4.56-5.13 for 35-37s.
- Ford 9-inch
- Dana 44 TTB Carrier break: 3.92 (3.73 & down use one carrier; 3.92 & up the other — confirmed by Yukon carrier listings). Non-Rubicon TJ rear is 30-spline; Rubicon TJ is 32-spline rear with air/electric locker variants by year. Practical ratios 4.56-5.13 for 35-37s.
- Ford 8.8-inch Carrier break: None (all ratios fit the same carrier; 31-spline Explorer/truck version is the strong one). 28-spline car vs 31-spline truck variants — confirm spline count. C-clip shafts are the weak point; eliminator kits exist.
- Dana 44 / Dana 50 TTB Carrier break: 3.92 (3.73 & down use one carrier; 3.92 & up the other — confirmed by Yukon carrier listings). Non-Rubicon TJ rear is 30-spline; Rubicon TJ is 32-spline rear with air/electric locker variants by year. Practical ratios 4.56-5.13 for 35-37s.
- Ford 10.25-inch / 9-inch by year
Ford 9-inch dominates the early era (no carrier break, drop-out third member — easiest regear in this dataset). Later trucks mix 8.8-inch rear. Dana 20 (2.46 low, early Bronco) and Dana 44 TTB complicate 'classic Ford' — presets above are the two most-searched combos.
Deciding? Run your exact combo in the regear comparison, then let the $39 Decision System turn it into a parts list, a budget and a shop-ready build sheet.
Sources
- MotorTrend/Novak NP435 Ford ratio listing (6.68/3.34/1.66 or 1.74/1.00, reverse 8.26)
- DieselHub/F150Hub BW1345 (2.72) and BW1356 (2.69) specifications
- Classic Bronco T18 ratio summaries (6.32/3.09/1.69/1.00)