F150 Gears & Driveline – Ring & Pinion Gears, Lockers, Axles & Re-Gear Kits

Why Gear Ratio Matters After You Install Bigger Tires

F-150 factory axle ratios are engineered for the factory tire size, and when you go bigger, the math changes. A truck with 3.55 gears and 32-inch tires effectively becomes a truck with approximately 3.25 gears when you bolt on 35-inch tires. That reduction in mechanical advantage means the engine has to work harder to turn each wheel, and the effect is noticeable everywhere: launch feels lazy, passing power drops, the transmission downshifts constantly on grades, towing feels like the truck is straining, and highway RPM climbs at cruising speeds. Installing taller gears restores the factory mechanical advantage and often makes the truck feel better than it did stock because the new ratio is optimized for the larger tires. The general rule of thumb is that 33-inch tires benefit from a bump to 3.73 gears, 35-inch tires pair well with 4.10 gears, and 37-plus-inch tires often need 4.56 or deeper ratios depending on engine choice and intended use.

Choosing the Right Gear Ratio for Your Engine and Tire Combo

The right gear ratio depends on your engine, tire size, transmission, and primary use case. EcoBoost trucks tolerate taller tires with less of a gear change because the turbos produce torque across a broader RPM range, but the 5.0L Coyote is a naturally aspirated engine that feels much better with a proper gear change any time you go past 33-inch tires. The PowerBoost Hybrid also benefits from gear optimization because the hybrid system's torque delivery works best when the engine is in its efficiency sweet spot. For daily drivers, towing rigs, and owners who spend most of their miles on highway, a slightly conservative gear choice keeps RPM reasonable at cruising speed. For off-road builds, rock crawlers, and trucks that spend their time in low-range and trail driving, deeper gears deliver more wheel torque and better crawl ratio. Match the gear choice to your actual use case and your engine's torque curve rather than just picking the deepest ratio available.

Ring and Pinion Sets, Master Install Kits, and Professional Installation

A gear change is not a bolt-on modification. It requires pulling the axle, removing the differential, pressing off the old ring and pinion, installing a new ring and pinion set, setting pinion depth and backlash to precise specifications, installing new bearings and seals, and reassembling the axle with the correct carrier shim setup. Quality ring and pinion sets come from manufacturers like Yukon Gear & Axle, Motive Gear, Nitro Gear, and Richmond Gear, and they're typically sold with matching master install kits that include all the bearings, seals, shims, crush sleeves, and hardware required for a proper installation. Unless you have real experience with axle setup (and the specialized tools to measure pinion depth, backlash, and gear pattern), gear installation is a job for a professional drivetrain shop. A poorly set up gear install will fail, often loudly and expensively, within a few thousand miles.

Differential Lockers: Real Off-Road Traction

Factory F-150s use open differentials in most trims, with some models offering an optional electronic locking rear differential. For serious off-road use, an aftermarket locker is one of the biggest performance upgrades you can make, because it forces both wheels on an axle to rotate together and prevents a lifted wheel from simply spinning uselessly while the other sits still. Selectable lockers like the ARB Air Locker let you engage and disengage on demand, combining full on-road comfort with full off-road traction. Automatic lockers like the Eaton Detroit Locker engage whenever wheel speed differs, delivering aggressive traction at the cost of some on-road drivability. Limited-slip upgrades like the Eaton TrueTrac use helical gears to deliver improved traction without the complexity of a selectable locker, making them an excellent middle-ground choice for daily-driven trucks that also see occasional off-road use.

Differential Covers, CV Axles, and Supporting Components

Heavy-duty aluminum or cast differential covers from brands like ARB, Mag-Hytec, and Yukon add capacity for additional gear oil (which helps with cooling under heavy towing or off-road loads) and provide impact protection for the differential housing against rocks and trail debris. Many also include drain plugs, fill plugs, and magnetic pickups for easier fluid service. CV axles on the front of 4WD F-150s take serious abuse on lifted trucks running larger tires, and upgraded axles from brands like RCV Performance deliver chromoly shafts, rebuilt CV joints, and the kind of strength that survives hard off-road use without breaking. U-joints, slip yokes, and driveshaft upgrades round out the category for trucks that need to handle serious off-road or towing loads.

Pairing Gear and Driveline Upgrades With Your Complete Build

Gear and driveline upgrades work best when they're planned as part of a complete build. If you're installing a lift kit and upgrading to larger tires, planning a gear change at the same time is far more efficient than doing it later. Pair deeper gears with a tune to optimize shift points and throttle response for the new ratio, and consider quality wheels that handle the added stress of off-road use. A complete, balanced build delivers far more performance and drivability than the sum of its parts.

F-150 Gears & Driveline FAQ

Do I really need to re-gear after installing 35-inch tires? For most owners, yes. The factory gearing is optimized for factory tire size, and 35-inch tires shift the effective ratio enough that acceleration, towing, and highway performance all suffer. A gear change restores lost performance and often makes the truck feel better than stock.

Can I install gears myself? Unless you have specialized axle setup experience and tools (dial indicator, case spreader, pinion depth tools, gear marking compound), gear installation should be done by a professional. The consequences of an incorrect setup are expensive.

Will re-gearing affect my truck's computer or tuning? Yes. The truck's computer needs to be reprogrammed to account for the new gear ratio so that speedometer, odometer, and shift points remain accurate. Most tuners and dealers can reprogram the axle ratio value in the ECM and ABS module.

Do gear changes affect fuel economy? After installing larger tires, a proper gear change typically restores fuel economy to something close to the original factory number, because the engine is no longer working outside its efficiency range. Going deeper than the original ratio compared to factory tires will reduce highway economy.

Are aftermarket lockers worth it for daily-driven trucks? Limited-slip differentials like the Eaton TrueTrac are excellent for daily drivers because they deliver off-road traction without affecting on-road manners. Selectable lockers like the ARB Air Locker add the ultimate off-road capability without any daily driving compromise, at the cost of a more complex install.