The 2017 Ram 2500 heavy-duty truck utilizes several factory tire sizes depending on trim level, wheel diameter, and single versus dual-rear-wheel configurations. The primary evolutionary milestones span 17-inch, 18-inch, and 20-inch rim diameters, accommodating Load Range E ratings required for heavy towing and payload capacities.
Introduction to Heavy-Duty Truck Tire Dynamics
The evolution of tire sizing on heavy-duty platforms like the 2017 Ram 2500 represents a careful balance between load-carrying capability, ride comfort, ground clearance, and electronic stability control calibration. As truck capabilities grew, manufacturers adjusted factory wheel and tire packages to handle higher gross vehicle weight ratings (GVWR) and increased torque outputs from powerplants like the 6.7L Cummins Turbo Diesel and the 6.4L HEMI V8.
For owners, enthusiasts, and fleet operators examining the 2017 Ram 2500 tire size evolution, understanding how factory dimensions dictate real-world performance is essential. Changing tire sizes impacts speedometer accuracy, transmission shift points, towing stability, and clearance within the wheel wells. This analysis breaks down the factory specifications, trim-specific variations, upgrade paths, and operational implications of tire sizing for the 2017 model year.
Factory Tire Options for the 2017 Ram 2500
Ram structured the 2017 2500 lineup across multiple trim levels—ranging from the base Tradesman to the utilitarian SLT, the off-road-oriented Power Wagon, the luxurious Laramie, and the top-tier Limited. Each trim came paired with specific wheel dimensions, which dictated the corresponding factory tire size.
Standard 17-Inch Wheel and Tire Configurations
Base models, such as the Tradesman and select heavy-duty configuration packages, frequently rolled off the assembly line with 17-inch steel or aluminum wheels. The standard metric size for these applications is LT245/70R17E.
- Width: 245 millimeters.
- Aspect Ratio: 70 percent sidewall profile relative to the width.
- Rim Diameter: 17 inches.
- Load Range: E (10-ply equivalent rating), crucial for supporting heavy tongue weights.
This size provides a narrower footprint, which reduces rolling resistance and cuts through loose snow or mud effectively, though it offers a visually conservative stance relative to higher-tier trims.
Mid-Tier 18-Inch Wheel and Tire Configurations
Moving up to mainstream trims like the SLT, Laramie, and Lone Star introduced 18-inch wheels as standard or optional equipment. The dominant factory tire size for these setups is LT275/70R18E.
- Width: 275 millimeters.
- Aspect Ratio: 70 percent.
- Rim Diameter: 18 inches.
- Load Range: E.
The LT275/70R18E provides a balanced compromise between sidewall height (crucial for soaking up road impacts when unladen) and tread width, enhancing cornering grip and braking stability under load compared to the narrower 17-inch variant.
Premium 20-Inch Wheel and Tire Configurations
For appearance packages and higher luxury trims (such as Laramie Longhorn and Limited), Ram offered 20-inch polished aluminum wheels. The factory specification for these larger rims is LT285/60R20E.
- Width: 285 millimeters.
- Aspect Ratio: 60 percent.
- Rim Diameter: 20 inches.
- Load Range: E.
While 20-inch wheels offer a more contemporary aesthetic and sharper steering response due to the shorter sidewall, they reduce the amount of rubber cushion between the road rim and the terrain, slightly firming up the ride quality over rough surfaces.
The Unique Case of the 2017 Ram 2500 Power Wagon
The 2017 Ram 2500 Power Wagon deviates significantly from standard 2500 models due to its factory off-road architecture, which includes a unique factory suspension lift and electronic locking differentials. The Power Wagon comes equipped exclusively with LT285/70R17D or E-rated all-terrain tires (historically Goodyear Wrangler DuraTrac tires in size LT285/70R17) mounted on unique 17-inch forged aluminum wheels. The taller 33-inch outer diameter matches the truck's raised ride height, optimizing ground clearance without requiring aftermarket modifications.
Summary of Factory Specifications
| Trim Level / Variant | Factory Tire Size | Wheel Diameter | Load Range | Primary Purpose |
|---|---|---|---|---|
| Tradesman (Base) | LT245/70R17E | 17 inches | E (10-ply) | Fleet utility, maximum sidewall cushion |
| SLT / Laramie (Standard) | LT275/70R18E | 18 inches | E (10-ply) | Balanced towing, daily driving comfort |
| Limited / Longhorn (Optional) | LT285/60R20E | 20 inches | E (10-ply) | Premium appearance, highway stability |
| Power Wagon | LT285/70R17D / E | 17 inches | D or E | Dedicated off-road traction, increased clearance |
The Mechanics of Load Ranges and Ply Ratings
When examining the evolution of heavy-duty truck tires, load-carrying capacity remains the primary engineering constraint. Unlike half-ton trucks (such as the Ram 1500) that typically utilize P-metric or standard Load Range C/SL tires prioritizing ride plushness, heavy-duty trucks require robust sidewall construction.
The letter designation at the end of a tire size (such as the "E" in LT275/70R18E) defines its load range.
- Load Range D (8-ply rating): Found on select specialized models like earlier Power Wagons to allow slightly more flex airing down off-road.
- Load Range E (10-ply rating): The industry standard for the vast majority of 2017 Ram 2500 configurations, capable of handling higher maximum air pressures (often up to 80 PSI) to support heavy pin weights from fifth-wheel trailers or heavy goosenecks.
Installing non-LT (Light Truck) tires or passenger-car metric tires on a Ram 2500 introduces severe safety hazards, including sidewall squirm, accelerated tread wear, excessive heat buildup under heavy loads, and potential tire failure.
Evolution of Sizing and Aftermarket Upsizing Considerations
Many owners look beyond factory tire sizes to improve aesthetics, enhance off-road capability, or achieve better traction in deep mud and snow. However, modifying tire dimensions on a 2017 Ram 2500 requires careful adherence to suspension geometry and axle specifications.
Stock Clearance Limits
Without a suspension leveling kit or lift kit, the 2017 Ram 2500 coil-spring front suspension limits front tire diameter.
- Maximum Recommended Diameter (Stock Suspension): Approximately 33 inches (such as the factory Power Wagon size of 285/70R17 or 275/70R18).
- Rubbing Points: Going beyond a 33-inch diameter or a significantly wider tread pattern (e.g., 12.50 inches wide) without altered wheel offsets will typically cause the inside tire shoulder to rub against the factory control arms at full steering lock.
Leveling Kits and Larger Tires
Installing a 2-inch to 2.5-inch front leveling kit alters the rake of the truck and provides additional clearance in the wheel wells. With a leveled front end, many owners successfully install 35x12.50R18 or 35x12.50R20 tires.
However, upsizing to a true 35-inch or 37-inch tire introduces secondary mechanical considerations:
- Gear Ratios: The 2017 Ram 2500 was available with axle ratios such as 3.42, 3.73, and 4.10. Taller tires effectively lower the numerical final drive ratio, reducing low-end towing acceleration and increasing transmission shift hunting unless recalibrated or re-geared.
- Speedometer and Transmission Calibration: Factory computers calculate vehicle speed and transmission shift points based on revolutions per mile. Changing tire size throws off the speedometer and odometer readings, which can also affect the Electronic Stability Control (ESC) and anti-lock braking system (ABS) thresholds. Using a digital programmer to update tire revs per mile is necessary.
- Front-End Wear: Heavier, larger tires increase unsprung weight, accelerating wear on ball joints, tie rod ends, and steering dampeners—components already subject to high stress in solid-front-axle architectures.
Maintenance, Inflation Pressures, and TPMS
Maintaining correct tire pressures on a 2017 Ram 2500 differs significantly from passenger vehicles. The Tire Pressure Monitoring System (TPMS) is calibrated to factory specifications, which often mandate high cold inflation pressures (e.g., 60 to 70+ PSI) when the truck is loaded.
The Unladen Ride Quality Dilemma
When operating an empty heavy-duty truck, running factory-recommended maximum pressures front and rear can result in a harsh, bouncing ride because the tires are inflated to support a maximum payload that isn't currently present.
- Door Jamb Placard: Always reference the certification label on the driver-side door jamb for minimum safe cold inflation pressures.
- Custom Tuning: Owners who install aftermarket tires with different load indices often utilize aftermarket programmer tools to adjust the TPMS threshold warning limits, preventing persistent dashboard alerts when running lower pressures unladen.
Frequently Asked Questions
What is the largest factory tire size that fits a stock 2017 Ram 2500?
The largest factory-approved size for standard 2500 models is the LT285/60R20 (approximately 33.5 inches tall), while the Power Wagon trim comes standard with LT285/70R17 tires, which also measure right around 33 inches in overall diameter.
Can I install passenger car tires on my 2017 Ram 2500 for a smoother ride?
No. Passenger car tires (P-metric) lack the internal ply construction and load capacity required for a heavy-duty three-quarter-ton truck. Doing so compromises towing safety, increases the risk of catastrophic blowout under load, and fails to meet the vehicle's GVWR requirements.
How do I correct my speedometer after installing larger tires?
Because changing tire dimensions alters your rolling circumference, you must use a digital OBD-II programmer or diagnostic tool capable of rewriting the Body Control Module (BCM) with the exact new tire revolutions-per-mile specification.
Why do my 2017 Ram 2500 tires wear unevenly on the edges?
Solid front axle trucks like the Ram 2500 place heavy demands on front-end alignment, particularly caster, camber, and toe settings. Worn track bar bushings, ball joints, or incorrect alignment angles frequently cause premature shoulder wear on heavy-duty truck tires.
What tire load range do I need for heavy fifth-wheel towing?
You should exclusively use Load Range E (10-ply rating) tires when towing heavy fifth-wheel or gooseneck trailers. These tires maintain structural integrity under high vertical pin weights and resist excessive sidewall flex during lane changes.
Conclusion and Next Actions
Understanding the 2017 Ram 2500 tire size evolution highlights the engineering trade-offs between load capacity, ride comfort, and mechanical longevity. Whether you are replacing original equipment manufacturer (OEM) tires with exact-match replacements or planning a mild upsize with a leveling kit, always prioritize proper Load Range E ratings, correct inflation pressures, and accurate computer calibration. Before purchasing aftermarket tire sizes, verify your current wheel width, check available clearance at full steering lock, and consult a professional alignment technician to preserve your truck's handling dynamics.
