Mud-Terrain Tires for Power Wagon (KM3 / Patagonia M/T / Open Country M/T)

For a Power Wagon you actually wheel hard, 35" or 37" mud-terrain tires are the right answer. 35s fit a 3" lift on factory wheels with spacers and leave the factory 4.10 gears usable. 37s need 4-5" of lift, +25mm spacers or aftermarket wheels, fender trimming, and a 4.56 regear — the factory 4.10s feel flat on 37s and run the transmission hot on grades. Pick the path before you buy the tires, because the tire is the cheapest part of the 37" decision.

The 2014 and later Power Wagon ships with LT285/70R17 (~33") tires on 4.10 gears behind a 6.4L Hemi (410 hp / 429 lb-ft), at a curb weight near 6,900 lb and a GVWR of 8,510 lb on 2019+ trucks. That combination is well matched from the factory for daily driving and light trail work.

One correction worth stating plainly, because it circulates in forum threads: the 2014+ Power Wagon is 6.4L Hemi only — the 5.7L belongs to the 2005-2013 trucks — and 4.30 is not an available ratio in these axles. The AAM 9.25" front and AAM 11.5" rear share ratios from a short list; the meaningful regear targets are 4.56 and 4.88.

Most Power Wagon owners overbuy here. Run this filter before spending.

Choose 35s (LT315/70R17, ~34.4") if you mix highway miles with moderate-to-hard trail, tow occasionally, or want to keep factory gears and wheels. This size clears a 3" lift on factory wheels with 1.5" spacers, or on factory wheels alone if you accept a rub at full articulation. Regear is optional — the 6.4 pulls 34.4s without complaint in normal driving. BFG KM3 in LT315 is the reference tire; the Milestar Patagonia M/T is the budget pick at meaningfully less money and meaningfully less tread life.

Choose 37s (LT37x12.50R17) only if rock crawling or deep technical terrain is the actual use case and you are committed to the full supporting build. On factory 4.10 gears, 37s make the truck feel gutless, the 6-speed hunts on grades, and transmission temperature climbs while towing. The regear is not a later upgrade — it is part of the tire.

1. 4-5" of lift — see the 4" mid-lift guide for the geometry work (track bars, caster, brake lines) that a coil-sprung Power Wagon requires, or the AEV DualSport system for a matched package.
2. Wheel offset or spacers — either +25mm spacers on factory wheels (wheel spacer guide) or aftermarket 17x9 wheels at -12mm to 0mm offset. Confirm against the Power Wagon tire fitment guide rather than a forum photo.
3. Fender trimming — inner liner trim is mandatory; the outer pinch weld often needs attention too. There is no configuration that avoids this.
4. Regear to 4.56, both axles — see the regear guide. Budget $1,200-1,800 done, and do both axles at once; mismatched ratios destroy the transfer case.
5. Speedometer recalibration. Going 33" to 37" is roughly a 12% error — an indicated 60 mph is about 67 mph actual, and the odometer under-counts by the same margin, which distorts every service interval. An AEV ProCal or equivalent tire-size programmer (~$200) corrects it. This also matters legally; a 12% speedometer error is not a defense.
6. Winch capacity re-check. The factory Warn 12,000 lb winch was rated against a stock truck. Add 37s, a steel bumper, and gear, and the effective margin shrinks — see the factory recovery points guide for why single-line pull drops as the drum fills.

The Power Wagon's front GAWR is 6,000 lb, which means each front tire must be rated for at least 3,000 lb. Shop by load index and load range, not by size. A 37" tire in a light-duty flotation casing exists, sells cheaply, and is under-rated for this truck.

• Load Range E LT casings are the safe default on a 3/4-ton
• Load Range D is acceptable in some 37" sizes — verify the published single-tire rating meets 3,000 lb before buying
• Avoid unbranded 37s entirely. A stock Power Wagon at ~6,900 lb chews cheap sidewalls, and a sidewall failure on a heavy truck at highway speed is not a flat tire, it is an incident

Set cold pressure conservatively and by load, not by the door placard number (which was written for the 33" stock tire). Torque lugs to 140 lb-ft and re-check after 50 miles — new wheels and spacers both settle.

BFGoodrich KM3 — the dominant Power Wagon choice in both 35 and 37. Proven sidewall construction, unusually good wet-road manners for a mud-terrain, and the tread survives rock. About $420 in LT315/70R17 and $530 in 37x12.50R17. This is the default recommendation.

Toyo Open Country M/T — ~$590 in 37. Aggressive shoulder lugs, excellent in mud and soft terrain, noticeably louder on highway than the KM3 and generally shorter-lived on pavement.

Nitto Trail Grappler M/T — ~$560 in 37. The quietest of the three on highway for a genuine M/T, with slightly less bite in deep mud. The right pick if the truck sees more pavement than the other two owners' trucks do.

Milestar Patagonia M/T — ~$310 in LT315/70R17. Real value, real capability, and real tradeoffs: shorter tread life and less refined road manners. Sensible on a truck that gets new tires often anyway.

Weight matters more than the spec sheet suggests. A stock 285/70R17 DuraTrac is roughly 57 lb. A 315/70R17 KM3 is around 68 lb; a 37x12.50R17 KM3 is around 82-88 lb. Adding ~30 lb of unsprung rotating mass per corner is why the regear and better shocks stop being optional — see the premium reservoir shock guide.

That is why the bottom-line advice holds: 37s are a $7-11k commitment once the supporting mods are counted, and they only earn it on a truck that genuinely crawls. A 35" KM3 setup on a 3" lift (3" mid-lift) delivers most of the off-road capability for roughly a third of the money.

Why it works

• 35s clear a 3" lift with no regear and no trimming beyond a tap of the inner liner
• 37s on a properly regeared Power Wagon make it one of the most capable near-stock trucks on the market
• KM3 sidewall construction is proven against Power Wagon weight
• Step-change in rock traction over an all-terrain

Trade-offs

• 37s make the regear mandatory ($1,200-1,800 done)
• 37s make fender trimming mandatory — no configuration avoids it
• 37s cost roughly 3-4 mpg
• 37s push the factory winch's effective margin toward marginal
• Mud-terrains are loud on highway, without exception
• 12% speedometer and odometer error until recalibrated

Tools required

• torque wrench
• tire-pressure gauge
• fender trim tools if going 37
• tape measure

Parts

Part	Vendor	Est. price
BFGoodrich Mud-Terrain T/A KM3 LT315/70R17 (34.4")	BFGoodrich	~$420
BFGoodrich KM3 LT37x12.50R17	BFGoodrich	~$530
Milestar Patagonia M/T LT315/70R17	Milestar	~$310
Toyo Open Country M/T LT37x12.50R17	Toyo	~$590
Nitto Trail Grappler LT37x12.50R17	Nitto	~$560
AEV ProCal module (speedometer / tire size recalibration)	American Expedition Vehicles	~$200

Sources

• BFGoodrich Mud-Terrain T/A KM3 — LT-metric and flotation specs
• Toyo Open Country M/T — product specs
• Nitto Trail Grappler M/T — product specs
• Ram Trucks — 2500 Power Wagon specifications

Related

• All-Terrain Tires for Power Wagon (BFG KO2 / Falken AT3W / Toyo AT3)
• Wheel Upgrade for the Power Wagon — 17", 18" and 20" Options
• Re-gear from 4.10 to 4.56 for 37s on Power Wagon
• All Ram Power Wagon guides & tools
• Browse the full DIY database

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Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.

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