F-150 RaptorPutting 37s on a Raptor: The Leveling Combo That Actually Works
Going from 35s to 37s is the most-searched Raptor modification, and it's also the one most people get wrong on the first try. The mistake is treating it like a lift. On a factory long-travel desert truck, 37s aren't a suspension upgrade — they're a fitment-and-geometry problem, and the right fix is small, specific, and very different from the spacer-and-coil kit you'd bolt onto a normal pickup.
To run 37s on a Gen 2 (2017–2020) or Gen 3 (2021–2023) Raptor that didn't come with the factory 37 package, you don't lift the truck — you level it. You add roughly 1.5–2 inches of front ride height with a preload spacer on top of the factory Fox front coilovers, and you replace the upper control arms with aftermarket arms that restore the front-end geometry that extra height throws off. That combination clears the bigger tire, keeps your alignment in range, and stops the tire and CV axle from contacting the arm at full stuff. A traditional spacer-and-coil "lift kit" is the wrong tool: it stiffens the ride, steals up-travel, and works against the long-travel suspension that makes the truck what it is.
If you're shopping Gen 3, the cheapest path to 37s is to buy a truck that already has the factory 37 package — Ford engineered the clearance, gearing-friendly tires, and hardware as a package, and matching it aftermarket costs more than the option did new.
Why 37s, and why it isn't a bolt-on
The appeal is real. A 37-inch tire adds about an inch of ground clearance at the axle, a bigger contact patch for sand and rock, and a stance that fills the Raptor's already-wide fenders. The factory 35s (a 315/70R17, roughly 34.4 inches in practice) are excellent, but 37s are the natural next step for owners who want more float in deep sand and more belly clearance on rock.
The catch is that the Raptor isn't a leaf-and-coil pickup with inches of empty fender to spare. It's a long-travel truck with around 13 inches of front travel and internal-bypass Fox shocks tuned to a specific ride height and tire diameter. A 37 is roughly 1.5–2 inches taller in diameter than the stock 35, which means at full compression the larger tire wants to occupy space the factory geometry assumes is empty. Add the truck's wide track and the front tire's proximity to the upper control arm, and you have two real contact risks: the tire rubbing the fender liner and front of the wheel well, and the tire or CV boot contacting the upper control arm near full stuff. Solving those without wrecking the suspension is the whole job. Our Raptor tire fitment guide lays out the exact measurements and clearances behind this.
The Gen 3 shortcut: the factory 37 package
If you have or are buying a Gen 3 (2021–2023), start here before spending a dollar on parts. Ford offered a factory 37 package that ships the truck with 37x12.50R17 tires on 17-inch beadlock-capable wheels, the correct ride height, and the hardware to support it — all engineered together and covered under warranty. Matching that aftermarket on a non-37 truck costs more than the factory option did, and it won't carry the factory validation.
If you're cross-shopping a 37-package truck against a standard 35-tire Gen 3, our 37 package versus non-37 comparison breaks down exactly what the package includes and whether the premium is worth it for how you'll use the truck. The short version: if you know you want 37s, buying the package is almost always cheaper and cleaner than converting later. The rest of this guide is for Gen 2 owners and Gen 3 owners who bought a non-37 truck and want to make the jump.
The combo that works: preload collar plus upper control arms
Here's the part most articles skip. The Raptor sits slightly nose-down from the factory. Clearing a 37 up front needs about 1.5–2 inches of additional front height, and the correct way to get it is a preload spacer (collar) that sits on top of the factory Fox coilover and increases spring preload, raising the front of the truck without replacing the shock. This keeps the long-travel Fox internals you paid for and avoids the stiff, short-travel ride of a budget coil-spacer lift. Camburg, Foutz, Icon, and SVC all sell preload collars or leveling kits designed for this. Expect roughly $150–400 for a quality collar kit, more if you go with a full leveling kit that bundles other parts.
Adding preload changes your front suspension geometry — it pushes the upper ball joint angle and shifts your camber and caster out of the factory window, and at the same time the raised, larger tire sits closer to the factory upper control arm. The fix for both problems is one part: aftermarket upper control arms. Quality UCAs (Camburg, SVC, Foutz, Icon) are built with relocated, higher-misalignment ball joints and uniball or heavy-duty bushings that restore correct geometry at the new ride height, add clearance for the 37 at full compression, and let the alignment shop dial caster and camber back into spec. Budget roughly $600–1,200 for a quality set. Our upper control arm guide covers uniball versus bushing tradeoffs, maintenance, and what separates a race-grade arm from a budget one, and the leveling and lift guide explains why this preload-plus-UCA approach is the correct one for a long-travel truck and why a conventional lift is not.
Run the collar without the arms and you'll likely run out of camber adjustment and risk tire-to-arm contact at full stuff. Run arms without the height and you haven't cleared the tire. The two parts are a system — that's the combo, and it's why "37s on a Raptor" is really a leveling-and-geometry job, not a tire swap.
Tires and wheels: getting the fitment right
The standard Raptor 37 is a 37x12.50R17, which matches the factory 37-package size and keeps you on a 17-inch wheel that leaves room for the big front brakes. Popular choices are the BFGoodrich All-Terrain T/A KO2 and KO3, the Falken Wildpeak A/T, and the Toyo Open Country in 37x12.50R17. A taller-load-range tire adds unsprung weight, so going to a 37 from a 35 noticeably increases rotating mass — that's part of why steering effort and stopping distance change, and part of the regear conversation below.
Wheel choice matters as much as tire size. You want a wheel with backspacing close to the factory spec (the factory Raptor wheel is roughly 17x8.5 with about 4.5 inches of backspacing / +6 mm to +18 mm offset depending on year) so the tire doesn't move outboard into the fender or inboard into the arm. Pushing the wheel out with the wrong offset or spacers increases scrub radius, adds steering load, and worsens rubbing — it's a common mistake. If you run in deep sand or rock and want to air down safely, a true beadlock wheel is worth considering; our beadlock conversion guide covers DOT-legal versus competition beadlocks and the maintenance they require. For day-to-day pressure management on the bigger tire, the air-down and TPMS guide walks through safe pressures and getting the sensors to read.
The parts everyone forgets: alignment, tie rods, clearance, and the spare
Alignment is non-negotiable. After the collar and UCAs go on, the truck must be aligned, with caster set as high and even as the arms allow — caster is what gives the Raptor its on-center stability at speed, and the larger tire makes a sloppy alignment feel worse. Budget $100–200 for an alignment at a shop that understands long-travel trucks. Skipping it means uneven tire wear on an expensive tire and a truck that wanders. The steering and alignment guide covers the target specs and why caster matters most here.
Tie rods take the load. The bigger, heavier tire puts more stress on the steering linkage, and the factory tie rods are a known weak point on hard-driven Raptors even on 35s. Owners running 37s and pushing the truck in the desert frequently upgrade to heavy-duty tie rods as cheap insurance against a trail-side bend — see the tie rod upgrade guide for which kits hold up and which are theater.
Clearance and rubbing. Even done right, a 37 can rub the front of the fender liner at full lock and compression. The usual fixes are trimming or relocating the plastic liner and, in some cases, the lower part of the fender — minor work, but plan for it rather than discovering it on the trail. Our fender and rock-chip guide covers liner trimming and protecting the freshly exposed edges.
The spare won't fit. This one strands people. A 37 does not fit in the factory under-bed spare location or on the factory carrier without modification, and the factory jack isn't rated to lift the truck on 37s safely. You need a spare-tire relocation or carrier solution and a proper jack before your first trip, not after a flat. The spare tire and jack on 37s guide covers the options and why this is a before-you-leave item.
Recalibrate the speedometer. The taller tire makes the speedometer read slow and throws off the odometer and shift points. A handheld programmer (SCT, HP Tuners) or a dealer/aftermarket tire-size recalibration corrects it. On Gen 2/3 this is also where many owners discover their TPMS needs a relearn after a wheel change — covered in the scan tools and TPMS relearn guide.
Do you need to regear? Usually not — and that surprises people
Going from 35s to 37s is only about a 5–6% increase in tire diameter, and the EcoBoost's torque plus the wide-ratio 10-speed automatic absorb that change far better than a naturally aspirated truck on a 6-speed would. Most owners running 37s on a stock-ish Gen 2 or Gen 3 do not need to regear, and the cost of regearing both differentials on these trucks ($1,600–3,000 done right) is hard to justify for a 5% change. The Gen 1 6.2L V8 trucks feel the change a bit more, but even there 37s are usually livable.
Where regearing earns its place is when you've added 37s and heavy armor, run a lot of towing, or plan to go past 37s. In that case the math changes. Our regear guide lays out the decision tree and the gear ratios that make sense for each case, and you can model your own setup with the gear ratio calculator. For most 37-inch builds, spend the regear money on the suspension and steering parts above instead.
What to watch for
The biggest mistake is over-lifting. People see "more height equals more clearance" and add 3+ inches with a tall spacer or a budget coil-over kit. On a long-travel Raptor that's counterproductive: every inch of preload you add is an inch of up-travel you lose, the ride gets harsher, and you stress the CV axles at a steeper angle. The factory engineers gave this truck its travel on purpose — the goal of the 37 build is to clear the tire with the least height change that does the job, not to make it tall.
Watch CV axle angles after the lift — a clicking or vibration that appears after the build often traces to CV plunge or angle, and the CV and axle service guide covers diagnosing it. Keep an eye on the new upper-control-arm ball joints or uniballs as a maintenance item, especially uniballs, which need periodic service. And don't forget the rear: 37s up front with a sagging factory leaf pack out back leaves the truck nose-high and ill-handling, so if the rear is tired, address it at the same time — the Deaver leaf pack upgrade is the common answer on Gen 1/2.
Costs and sources
A realistic budget for a done-right 37 conversion on a non-37 Gen 2 or Gen 3, excluding the tires and wheels themselves:
Preload collar / leveling spacer: $150–400 (Camburg, Foutz, Icon, SVC).
Aftermarket upper control arms: $600–1,200 a pair (uniball or HD bushing).
Heavy-duty tie rods (recommended): $300–700.
Alignment: $100–200 at a long-travel-literate shop.
Speedometer recalibration: $0 (handheld you may already own) to ~$400 for a programmer.
Spare relocation / carrier: $200–1,000+ depending on the solution.
Tires (37x12.50R17, set of 5): roughly $1,800–2,800 depending on brand.
All in, a non-37 truck reaches a clean, reliable 37-inch setup for roughly $3,000–6,000 depending on how far you take the wheels, tires, and spare solution. That's the number that makes the factory 37 package such a good deal on a Gen 3 if you can find one — Ford did this engineering for less than you can replicate it. Whichever path you take, build it as a system: height to clear the tire, arms to fix the geometry, steering to take the load, and an alignment to tie it together. If you're still weighing whether to start from a 37-package truck, our used Raptor buyer's guide covers verifying the package, and the Raptor overview frames where 37s fit in the bigger build picture.