Ford Bronco
1987–91
Factory gearing, tires, angles and brakes for the Bronco, and what the usual upgrades do to it. Every number is from the maker's own figures unless the calculators say otherwise. A few figures here are still waiting on a factory document; the calculators mark them.
Tire upgrades, worked out
Std P235/75R15XL on 15x6, 3.08s, from P235/75R15| Tire | Height | Under the diffs | Speedo at 65 | RPM at 65 | Gears for daily | Open |
|---|---|---|---|---|---|---|
| 31x10.50R15 | 31.0 in | +1.1 in | 61 mph | 2,171 | 3.73 | Open → |
| 32x11.50R15 | 32.0 in | +1.6 in | 59 mph | 2,103 | 3.73 | Open → |
| 33x10.50R15 | 33.0 in | +2.1 in | 57 mph | 2,039 | 3.73 | Open → |
| 33x12.50R15 | 33.0 in | +2.1 in | 57 mph | 2,039 | 3.73 | Open → |
| 35x12.50R15 | 35.0 in | +3.1 in | 54 mph | 1,923 | 3.73 | Open → |
Stock turns 2,330 rpm at 65 in top gear. Flotation sizes are nominal; most measure a little short mounted.
Trims
2 we have figures for| Trim | Tire | Transmission | Axle | Angles | Clearance | Open |
|---|---|---|---|---|---|---|
| Std P235/75R15XL on 15x6 | P235/75R15 | 4-speed manual, 5-speed overdrive manual, 3-speed automatic, 4-speed automatic overdrive | 3.08 / 3.55 / 4.1 | 30.8 · 18.9 · 16.2 | 9.1 in | Use → |
| Optional 31x10.50R15C on 15x8 | 31x10.50R15 | 4-speed manual, 5-speed overdrive manual, 3-speed automatic, 4-speed automatic overdrive | 3.55 / 4.1 | 30.8* · 18.9* · 16.2* | 9.1 in* | Use → |
* The maker doesn’t publish this figure for that trim, so it shows the closest trim’s (same tire where we have one), or a close relative’s that shares the same body or front end. Hover the star to see which.
Size
- Wheelbase
- 104.7 in
- Front overhang
- 30.5 in
- Rear overhang
- 45.3 in
- Height
- 74 in
- Body
- SUV
- Stock tires
- 31x10.50R15, P235/75R15
Transmissions and low range
- 4-speed manual (Warner T-18/T-19), 1987
- 6.32 · 3.09 · 1.69 · 1
- 5-speed overdrive manual (Mazda M5OD-R2), 1988+
- 3.91 · 2.24 · 1.49 · 1 · 0.8
- 3-speed automatic (C6)
- 2.46 · 1.46 · 1
- 4-speed automatic overdrive (AOD, 302)
- 2.4 · 1.47 · 1 · 0.67
- Low range, bw1356
- 2.69:1
Axles
- Front
- Dana 44 Twin Traction Beam
- Rear
- Ford 8.8 in
- 3.08 ratio
- Std P235/75R15XL on 15x6
- 3.55 ratio
- Std P235/75R15XL on 15x6, Optional 31x10.50R15C on 15x8
- 4.1 ratio
- Std P235/75R15XL on 15x6, Optional 31x10.50R15C on 15x8
- Ratios made for it
- 3.73 · 4.1 · 4.56 · 4.88 · 5.13
Brakes
- Front rotor
- 11.72 in, 298 mm
- Front caliper piston
- 73.0 mm
- Rear drum
- 11.03 in, 280 mm
- Rear
- drum
Suspension
- Front
- Twin Traction Beam, radius arms, coil springs
- Rear
- leaf springs, solid axle
- Rear layout
- Leaf springs
Fuel economy
- EPA highway, automatic
- 14 mpg
- EPA highway, manual
- 15 mpg
- Rated years
- 1987–1991, 4WD
Brake upgrades
What bigger tires need →- Desolate Motorsports 80-96 Bronco / 4WD F-150 big front brake kit+13% brake torque11.7 → 13.0 in rotor · 4-piston · 16 in wheels or bigger · $1,900Base price; $1,899.99 to $2,147.99 with options. Listing says it does not fit the 1987 integrated hub design.
Aftermarket bumpers
5 listedMakers almost never publish angles, bottom heights or how far a bumper tucks, so these fill in as owners measure them. Measured yours? Add it on the rig page and every owner of this Bronco sees how it does on their tires and lift.
Front 2
Every calculator, set up for the Bronco
Source: auto-brochures.com. 8.8 in carriers come in two series split around 3.08/3.27, so a 3.08 truck needs a new carrier for 3.55 and up.
Use at your own risk. These calculators are here to help you plan and to inform your decisions, not to sign off on a build. Many numbers are estimates worked out from factory figures, and some factory figures are not yet confirmed. Check every number against your own truck, its manuals and a qualified shop before you buy parts, cut, weld, lift, regear or drive on it. Long Range Desert Tools is not liable for anything you do based on these calculators or their results. The full terms are in our policies.