What is the bolt pattern on a Ram 1500 TRX?

The TRX uses a 6x139.7mm (also written 6x5.5") bolt pattern with a 77.8mm center bore and M14x1.5 lug studs — the same wheel mounting specs as the rest of the fifth-generation (DT) Ram 1500. Any wheel you buy must match all three: bolt pattern, hub bore, and lug thread.

What size wheels and tires come on the TRX from the factory?

The TRX ships on 18x9-inch wheels (beadlock-capable on some trims) wearing 325/65R18 tires — about a 35-inch-tall, ~12.8-inch-wide all-terrain. That factory 35" tire is already large, which is why the TRX needs far less lift than most trucks to run a bigger meat.

How big a tire can I fit on a TRX?

Stock, the TRX already runs a 35" tire, and many owners fit 37s with the right wheel offset and modest leveling or trimming. Going to 37s or larger changes your effective gearing, loads the driveline harder, and usually needs an alignment and careful offset choice to avoid rubbing. Always confirm a specific size against your exact wheel offset, lift, and trim before buying.

Do I need new TPMS sensors when I change wheels?

If you buy a second set of wheels (for winter or off-road tires), you'll need a second set of compatible TPMS sensors so the truck reads pressures correctly. Factory takeoff wheels usually come with sensors already installed; bare aftermarket wheels do not.

Ram TRX Wheel & Tire Fitment Guide: Bolt Pattern, Offset & Tire Sizes

Wheels and tires are the single most-visible change you can make to a Ram 1500 TRX — and the easiest to get wrong. Buy a wheel with the wrong offset and it rubs the fender or the control arm; buy the wrong bolt pattern and it won’t even bolt on. The good news is the TRX’s fitment specs are well-defined, and because it leaves the factory on a 35-inch tire, you have more room to work with than almost any other truck. This guide covers the exact numbers you need, what offset and backspacing actually mean, and which tire sizes are realistic stock, leveled, and lifted. For the suspension side of a bigger-tire build, pair it with our TRX suspension & lift guide and the year-by-year fitment guide.

The numbers that must match

Every wheel you consider has to match the TRX’s mounting hardware exactly. There is no fudging these:

Bolt pattern: 6x139.7mm (a.k.a. 6x5.5”). Shared across the fifth-gen (DT) Ram 1500, so DT-fit wheels bolt to a TRX.
Center bore (hub bore): 77.8mm. The wheel should be hub-centric to this — or use hub-centric rings — so the wheel rides on the hub, not the lugs.
Lug studs: M14x1.5 thread. Match your lug nuts (and any spacers) to this thread and the correct seat type.
Factory wheel size: 18x9 inches (beadlock-capable on some trims), running 325/65R18 tires — roughly 35” tall × 12.8” wide.

Get those four right and a wheel will physically mount. Whether it clears your suspension and fenders is the next question — and that’s where offset comes in.

Offset and backspacing, explained

These two numbers decide how far the wheel and tire sit in or out relative to the truck:

Offset is the distance (in mm) between the wheel’s mounting face and its centerline. Positive offset tucks the wheel inboard (toward the truck); negative offset pushes it outboard (a wider, more aggressive stance). Factory TRX wheels run a modest positive offset.
Backspacing measures the same thing from the back lip of the wheel to the mounting face (in inches). More backspacing = wheel tucked in; less backspacing = wheel poked out.

Why it matters on a TRX: push the wheel out (lower/negative offset, less backspacing) for a wider, more planted look and to clear a bigger tire from the suspension — but too far and the tire rubs the fender at full lock or full compression, and the wider track adds stress to wheel bearings. Tuck the wheel in (higher offset) and you risk the tire hitting the upper control arm or brake components. Most owners running larger tires drop offset moderately from stock to gain clearance without inviting rub. When in doubt, match a proven TRX-specific offset rather than guessing.

Tire sizes by setup

Because the TRX already wears a 35” tire, your upgrade path is different from a normal half-ton:

Stock (35” / 325/65R18): the factory size. Plenty of owners simply replace worn tires with the same size in a more aggressive all-terrain or mud-terrain and call it done — no lift, no rubbing, no speedometer error.
Leveled (front bump only): a modest front level closes the factory rake and buys a little clearance. It doesn’t add much tire room on its own, but it helps a 35” or borderline-37” fit sit cleaner. See the lift guide.
37” tires: the popular “big” step. Realistic on a TRX with the right offset and usually a modest level and/or light fender trimming. Expect an alignment, a heavier steering feel, and some effective re-gearing (the truck feels slightly lazier off the line and reads speed low unless recalibrated).
Beyond 37”: possible with real lift, wheel choice, and trimming, but you’re now trading daily drivability and driveline stress for looks/clearance. Plan the whole build.

Two things bite everyone who goes bigger: speedometer error (a taller tire makes the truck under-report speed and odometer distance until recalibrated) and effective gearing (a taller tire is like a numerically lower axle ratio — softer acceleration, more strain towing). Neither is a deal-breaker, but budget for a tune/recal and know they’re coming. If you tow, read our towing accessories list before adding big meats.

Load rating — don’t skip this

The TRX is a heavy truck (well over 6,000 lb) making 702 hp. Whatever tire you choose, respect the load index and range for the vehicle — a tire that’s fine on a lighter half-ton can be under-spec here, especially if you tow or haul. Stick with a load rating at or above the factory tire’s, and set pressures to the door-jamb placard (adjusted for a different-size tire). This is one place where “close enough” isn’t.

Wheels: new vs. used vs. factory takeoffs

New aftermarket wheels: browse the wheels & tires category on Amazon for finishes and offsets — just verify the 6x139.7 / 77.8mm / M14x1.5 specs and a TRX-appropriate offset before buying.
Factory takeoff wheels & tires: when owners upgrade, they sell their factory 18x9 wheels and 35” tires — often nearly new, frequently with TPMS sensors installed. That’s one of the best values on the used market, and eBay Motors is where they trade. Use the factory takeoff button above.
Used/OEM and beadlock wheels: eBay Motors is also the right marketplace for the beadlock-capable factory wheels and one-off sets. See the eBay buttons above.

Don’t forget the small parts that make a wheel swap work: correct lug nuts for your seat type, hub-centric rings if the wheel’s bore is larger than 77.8mm, quality wheel spacers (only if needed, and matched to M14x1.5), and a second set of TPMS sensors if you’re running two wheel sets.

How to buy

New wheels, tires, lug hardware, TPMS: Amazon Automotive — see the wheels & tires category.
Factory takeoff sets, used/OEM/beadlock wheels: eBay Motors, via the search buttons above (each tagged for clean attribution).

Confirm every wheel against the four hard specs — 6x139.7 bolt pattern, 77.8mm hub bore, M14x1.5 lugs, and a TRX-proven offset — before you buy, plan for an alignment and speedometer recal if you go taller than 35s, and match your tire’s load rating to the truck. Do that and your TRX will sit right, clear right, and drive right for years. Next, dial in the suspension in the lift & suspension guide, and if bigger tires mean harder stops, read the brake upgrade guide.