Tire Size 275/65r18 vs 35×12.50r18

The main difference between 275/65R18 and 35×12.50R18 tires is their diameter. 35×12.50R18 tires are 2.95 inches (74.98 mm) larger in diameter than 275/65R18 tires.

275/65r18 vs 35×12.50r18

This table compares the 275/65R18 and 35×12.50R18 tire sizes for easy understanding.

275/65r18 35×12.5r18 Difference
Tire Height 32.07″ Tire Height 35.03″ 2.95 inch
Tread Width 10.83″ Tread Width 12.52″ 1.69 inch
Sidewall Height 7.04″ Sidewall Height 8.51″ 1.48 inch
Circumference 100.77″ Circumference 110.04″ 9.27 inch
Revs Per Mile 628.78 Revs Per Mile 575.79 -52.99
Speedometer Reading 20 mph Speedometer Reading 21.84 mph 1.84 mph

Fitment Guide

Replacing 275/65R18 tires requires matching the overall diameter within 3% to avoid clearance issues or speedometer inaccuracies.

The 35×12.50R18 is 9.2% larger in diameter, so it may require modifications like a suspension lift to fit correctly. The width is also 15.6% wider, which can cause rubbing without widening the wheel wells.

Ground Clearance

With a diameter of 2.95 inches larger, the 35X12.5R18 tire size provides nearly 3 inches of additional ground clearance over the 275/65R18 size.

This added clearance is extremely beneficial for off-roading, allowing the vehicle to traverse larger obstacles and uneven terrain without scraping. However, the larger overall diameter causes the speedometer reading to be 8.4% lower than the actual speed.

Gas Mileage

The 35×12.50R18’s larger size and heavier weight will likely reduce fuel efficiency compared to the 275/65R18. More rubber on the road increases rolling resistance, requiring more fuel to maintain speed. The heavier rotational mass also requires more energy to accelerate.

Ride Comfort

The 35X12.5R18’s taller sidewall and greater air volume absorb bumps and impact more effectively than the lower-profile 275/65R18.

This cushier ride quality suits the rugged off-road environment but results in more body roll on pavement. The 275/65R18 offers a sportier, more responsive ride.


Visually, the 35×12.50R18 appears larger overall with its taller sidewall and wider tread. This can provide an aggressive, rugged look suited to trucks and SUVs.

The lower-profile 275/65R18 has a sportier, performance-oriented aesthetic, contributing to aerodynamic efficiency.

Handling & Stability

The 275/65R18’s shorter, stiffer sidewall enhances responsiveness and handling precision on the pavement. In contrast, the 35×12.50R18’s flex can delay reactions but provides stability off-road. Both deliver responsive, stable handling in their intended usage.

Noise & Vibration

Expect more road noise and vibration from the 275/65R18 as its stiff sidewall transmits more noise into the cabin. The 35×12.50R18 dampens vibrations through the tires’ additional air volume and sidewall flex, promoting a quieter ride.

Durability & Wear

The 275/65R18’s smaller size could allow for slightly more even wear and longer tread life. Meanwhile, the larger 35×12.50R18 endures more impacts off-road, but its weight adds stress to components. Both feature durable construction.

Adverse Conditions

In snow or ice, the narrower 275/65R18 may cut through to the pavement more effectively. The meatier 35×12.50R18 provides extreme traction in mud, rocks, and other off-road terrain.


Speedometer Difference

At an actual speed of 20 mph, the 275/65r18 equipped vehicle’s speedometer will read 20 mph. But with 35×12.50r18 tires, the speedometer will read around 21.84 mph at that actual speed due to the larger diameter. This speedometer discrepancy of nearly two mph is significant to note.

Alternative For 275/65R18
It is recommended that the overall diameter of the new tires be within 3% of the overall diameter of the original tires.

Tire Size Overall Diameter Difference
225/75R18 31.3″ (795 mm) -2.5%
285/60R18 31.5″ (799 mm) -2%
265/65R18 31.5″ (801 mm) -1.7%
245/70R18 31.5″ (801 mm) -1.7%
235/75R18 31.9″ (809 mm) -0.7%
255/70R18 32.1″ (815 mm) 0%
305/60R18 32.4″ (823 mm) 1%
285/65R18 32.6″ (827 mm) 1.5%
265/70R18 32.6″ (829 mm) 1.7%
375/50R18 32.8″ (833 mm) 2.2%

Alternative For 35X12.50R18
It is recommended to choose tires with an overall diameter that is no more than 3% different from the original tire’s diameter.

Tire Size Diameter Difference
285/75R18 34.8″ -0.57%
295/70R18 34.3″ -2%
305/70R18 34.8″ -0.57%
325/65R18 34.6″ -1.14%
34×12.5R18 34.0″ -2.86%
315/70R18 35.4″ 1.14%
35x13R18 35.0″ 0%

Our Observation
The 35×12.50R18’s larger overall size provides greater ground clearance and traction for off-road driving. At the same time, the 275/65R18 offers better fuel efficiency, handling, and a smoother ride on paved roads.

While the 35-inch tire suits those frequently going off-road, the 275 is likely the better option for most drivers who value responsive on-road performance and comfort.

Carefully considering how these tire sizes differ in diameter, width, sidewall height, and other factors can help determine the best fit for your usage needs. I suggest consulting a knowledgeable tire specialist for personalized recommendations tailored to your vehicle.

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