Ford Bronco II
1989–90

Factory gearing, tires, angles and brakes for the Bronco II, 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.

Use this truck in the calculators

94 in wheelbase · 29.6 in front · 38.2 in rear overhang

Stock tireP205/75R1527.1 in tall

Axle ratio3.45–4.1Factory, by trim

Crawl ratio15.5:1First × low × axle

Angles26.2 · 20.4 · 25.1°Approach, breakover, departure

Clearance7.1 inFactory figure

Highway mpg19EPA, 20 with the manual

Tire upgrades, worked out

2.9 V6, 5-speed or A4LD, P205/75R15, 3.45s, from P205/75R15

Tire	Height	Under the diffs	Speedo at 65	RPM at 65	Gears for daily	Open
235/75R15	28.9 in	+0.9 in	61 mph	2,114	3.73	Open →
31x10.50R15	31.0 in	+1.9 in	57 mph	1,970	4.1	Open →
32x11.50R15	32.0 in	+2.4 in	55 mph	1,908	4.1	Open →
33x10.50R15	33.0 in	+2.9 in	53 mph	1,850	4.56	Open →
33x12.50R15	33.0 in	+2.9 in	53 mph	1,850	4.56	Open →

Stock turns 2,252 rpm at 65 in top gear. Flotation sizes are nominal; most measure a little short mounted.

Size

Wheelbase: 94 in
Front overhang: 29.6 in
Rear overhang: 38.2 in
Height: 68 in
Body: Short wheelbase SUV
Stock tires: P205/75R15

Transmissions and low range

5-speed overdrive manual (Mitsubishi FM146): 3.769 · 2.21 · 1.516 · 1 · 0.81
4-speed automatic overdrive (A4LD): 2.47 · 1.47 · 1 · 0.75

Axles

Front: Dana 28 TTB, Dana 35 TTB on late builds (from Nov 1989 per Wikipedia, Nov 1990 per The Ranger Station)
Rear: Ford 7.5 in
3.45 ratio: 2.9 V6, 5-speed or A4LD, P205/75R15
3.73 ratio: 2.9 V6, 5-speed or A4LD, P205/75R15
4.1 ratio: 2.9 V6, 5-speed or A4LD, P205/75R15
Ratios made for it: 3.73 · 4.1 · 4.56

Brakes

Front rotor: 10.87 in, 276 mm
Front caliper piston: 66.0 mm
Rear drum: 9.00 in, 229 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: 19 mpg
EPA highway, manual: 20 mpg
Rated years: 1989–1990, 4WD

Every calculator, set up for the Bronco II

Tire sizeBigger tires: speedo, clearance, angles and brakes.Compare tires RegearHighway RPM on every ratio and mpg.Pick your gears Crawl ratioHow slow it creeps, against other trucks.Work out crawl SpeedometerWhat it really reads on new tires.Fix your speedo LinksAnti-squat and what a lift does to it.Check your links Your rigBuild sheet and measured angles.Start a build sheet LeaderboardsWhere the Bronco II ranks against every stock truck.See where it ranks

Source: therangerstation.com. Dana 28 TTB has very limited ring-and-pinion choices; Dana 35 TTB late trucks have more.

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.

Ford Bronco II1989–90