Tire Size 325/65r18 vs 35×12.50r18

The main difference between 325/65r18 and 35×12.50r18 tires is in the section width. The 325/65r18 tire size is about 0.28 inch wider than the 35×12.50r18 tire size. This width difference impacts various performance factors between the two tire sizes.

Tire 1 Front View
Width
Dia.
Tire 2 Front View
Width
Dia.
Tire 1 Side View
Tire 1 Wheel
circumference 1
Circ.
Rim
Wall
Revs/Mile
Tire 2 Side View
Tire 2 Wheel
Circ.
Rim
Wall
Revs/Mile
/ R
/ R
Parameter235/35 R18205/40 R18Differ.
Tire Height
Section Width
Circumference
Sidewall Height
Revolutions
Rim Size

Fitment Guide

The new size should be within 3% of the original tire’s overall diameter when replacing tires to prevent clearance issues or speedometer inaccuracies.

At 1.1% difference in overall diameter, switching between these two sizes should not cause major fitment issues. However, the 35×12.50R18 is slightly smaller, so it may have slightly more room for fitment without modifications.

Gas Mileage

With a narrower section width and lower diameter, the 35×12.50r18 likely has marginally better fuel efficiency over the 325/65r18.

The wider 325 tire has more rolling resistance and rotational mass, damaging gas mileage. The incrementally better economy of the 35×12.50r18 for daily driven vehicles could add up.

Ground Clearance

The 35×12.50r18 tire size provides 0.2 inches less ground clearance than the 325/65r18, a modest but potentially meaningful difference for off-road use.

This reduced clearance also corresponds to a slightly higher speedometer reading compared to the 325/65r18.

Ride Comfort

Differences in ride comfort should be minor between these sizes. The 35×12.50r18 shorter sidewall is stiffer, transmitting more road impacts into the cabin.

But with only 4.99mm sidewall height difference, impact harshness variability is low. Overall, both provide comfortable ride quality.

Tire Size 35x12.50r18 in Metric

Aesthetics

Visual differences are subtle, with the 325/65r18 appearing barely “stretched” relative to the 35×12.50r18.

Subjectively, the 35×12.50r18 more proportional look between tread width and sidewall height suits the aesthetics of trucks and SUVs well.

Handling & Stability

The 35×12.50r18 offers a handling advantage over the 325/65r18, with a shorter, stiffer sidewall promoting responsiveness and nimble reactions to driver inputs.

But the difference is very small, so both remain stable and inspire handling confidence.

Noise & Vibration

Consistent with comfort impressions, the 35×12.50r18 transmits marginally more road noise and vibration through its shorter sidewall.

However, both tires keep the cabin quiet and isolated from road impacts. Differences only manifest over very uneven surfaces.

Durability & Wear

With a lower profile and narrower tread, the 35×12.50r18 should theoretically exhibit slightly more even tire wear over time.

This projects to marginally enhance tread life durability. But in practice, differences are often insignificant between these sizes.

Adverse Conditions

Both tires perform well across rain, snow, ice, and light off-road conditions. The 325/65r18 added ground clearance gives it a slight edge for clearing obstacles or deeper snow.

Still, the 35×12.50r18 responsiveness aids traction and control. Overall capability is strong for both.

Speedometer Difference

At an actual vehicle speed of 20 mph, the speedometer reads 20.23 mph with 35×12.50r18 tires equipped. But with 325/65r18 tires, it reads 20 mph.

So, the 35×12.50r18 causes the speedometer to read 0.23 mph lower than the 325/65r18 at the same actual speed.

How Tall Is A 325/65r18 Tire?

The overall height of the 325/65r18 tire is 34.6 inches (879 mm), measured from the bottom to the highest point at the top of the tire.

Are 325 Tires The Same As 35?

The 325/65R18 and 35/12.50R18 tires are not the same but have some similarities. The main differences between these two tire sizes are:

  • Diameter: The 325/65R18 tires have a diameter of 34.63 inches, while the 35/12.50R18 tires have a diameter of 35.0 inches. This makes the 35/12.50R18 tires slightly larger in diameter than the 325/65R18 tires.
  • Width: The 325/65R18 tires are more comprehensive than the 35/12.50R18 tires.
  • Speedometer Difference: The 35/12.50R18 tires have a 1.1% speedometer difference compared to the 325/65R18 tires.

35×12.50r18 Equivalent

The equivalent metric size for 35×12.50R18 is 315/70R18. This means that the tire has a width of 315 millimeters, an aspect ratio of 70%, and fits on an 18-inch rim. The tire diameter for 35×12.50R18 is 35.0 inches.

325/65r18 vs 35x12.50r18

How Much Taller Is A 35×12.50r18 Tire Than A 325/65r18?

The 35×12.50R18 tire is approximately 0.39 inches (9.98 mm) taller than the 325/65R18 tire. This difference in diameter can affect the vehicle’s handling and ground clearance.

325/65r18 vs 35×12.50r18

Our Observation
Based on the minor differences between these two tire sizes, neither emerges as an unambiguously better choice. The 325/65R18 offers slightly more ground clearance for off-roading, while the 35X12.50R18 provides marginally better fuel economy and handling precision.

However, real-world variability often makes these small advantages negligible. Given the comparable overall performance, we recommend selecting based on aesthetic preferences and intended vehicle application.

Truck and SUV drivers prioritizing clearance could favor the 325/65R18, while those valuing responsiveness may prefer the 35X12.50R18. But for most purposes, either tire size effectively meets needs.

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