Tire Size 235/70r15 vs 235/75r15

235/70r15 vs 235/75r15

The main difference between tire sizes 235/75r15 and 235/70r15 lies in the aspect ratio, precisely the sidewall height. The 235/75r15 has a taller 75 aspect ratio sidewall, while the 235/70r15 has a shorter, 70 aspect ratio sidewall.

This seemingly minor difference in sidewall height impacts many performance factors, including ride comfort, handling, noise, and more.

235 75r15 vs 235 70r15

Fitment Guide

The overall diameter of 235/75r15 tires is 3.2% larger than 235/70r15 tires. This marginal difference likely won’t require any modifications for fitment.

Both sizes should mount directly onto the same 15-inch rims and fit within standard wheel wells. Replacement tires should be within 3% of the original size to maintain proper speedometer accuracy and prevent clearance issues.

Ground Clearance

The taller sidewall and larger diameter of 235/75r15 tires provide 0.46 inches (11.75mm) more ground clearance than 235/70r15. This added clearance benefits light off-road driving, clearing obstacles, and preventing wheel/body damage over rough roads.

However, the larger 235/75r15 diameter causes a lower speedometer reading by around 3-4 mph at highway speeds.

Gas Mileage

With less rubber mass and a slightly smaller contact patch, 235/70r15 tires will likely provide marginally better fuel efficiency over 235/75r15 tires.

The larger 235/75r15 diameter and width increase resistance and rotational mass, damaging gas mileage. This difference is minor but could amount to 0.5 mpg or more improvement.

Ride Comfort

The extra sidewall cushioning of 235/75r15 tires better absorbs impacts from road irregularities, cracks, and potholes.

This results in a smoother, more comfortable ride over uneven pavement than the shorter sidewall 235/70r15 tire. The added sidewall flex also dampens cabin noise and vibration.

Aesthetics

Visually, the difference between these sizes is subtle. The 235/75r15 will have a slightly taller sidewall, giving a modest “stretched” look compared to the 235/70r15.

This taller profile suits some vehicles better aesthetically, providing a more rugged, off-road-oriented appearance.

Handling & Stability

With a shorter, stiffer sidewall, the 235/70r15 tire offers sharper handling response and cornering. The more flexible 235/75r15 sidewall decreases handling precision slightly. However, both sizes deliver stable, predictable handling for regular driving.

Noise & Vibration

Expectedly, the 235/70r15 transmits more road noise and vibration to the cabin due to its shorter, less flexible sidewall.

The extra sidewall of the 235/75r15 better isolates and absorbs noise before it reaches passengers. But differences are minor, with both sizes offering a smooth, quiet ride.

Durability & Wear

The 235/70r15’s shorter sidewall and smaller contact patch may promote more even treadwear, potentially extending tread life marginally.

Conversely, the larger 235/75r15 size endures more mechanical stress, which could accelerate the wear of suspension components.

Adverse Conditions

Performance of both sizes in rain, light snow, and off-road conditions is comparable. The extra ground clearance of the 235/75r15 provides a slight advantage over obstacles, while the 235/70r15’s shorter sidewall makes it more responsive.

Speedometer Difference

The speedometer will read slightly higher with 235/75r15 tires compared to 235/70r15 at the same actual vehicle speed.

For example, at an actual speed of 20 mph, the speedometer will read 20.66 mph with 235/75r15 tires versus only 20 mph with 235/70r15 tires.

This 0.66 mph difference is because the larger 235/75r15 tires have a slightly larger overall diameter, causing slightly faster rotation at the same speed. Overall, the speedometer reading will be slightly higher with the larger 235/75r15 tires.

 

 

Can I Use 235/75r15 Tires Instead Of 235/70r15?

Using 235/75r15 tires instead of 235/70r15 tires is not advisable. The diameter difference is 3.3%, exceeding the recommended 3%. This variance can affect speedometer accuracy and impact vehicle performance.

Maintaining a diameter within the specified range is crucial to ensure proper function and safety.

How Much Taller Is A 235/75r15 Tire Than 235/70r15?

The 235/75r15 tire is 0.93 inches (23.5 mm) taller than the 235/70r15 tire. The specific height for the 235/70r15 is 27.95 inches (710 mm), while the 235/75r15 measures 28.88 inches (733.5 mm) tall.

What Does 235/75r15 Mean?

The tire size 235/75r15 refers to its dimensions. The first number (235) is the width in millimeters, the second (75) is the aspect ratio (sidewall height as a percentage of width), and the “r15” indicates a 15-inch rim diameter. The tire size 235/75R15 can be expressed as 28.9×9.3R15 in inches.

What Does 235/70r15 Mean?

The tire size “235/70r15” indicates a tire width of 235 millimeters, an aspect ratio of 70% (height as a percentage of width), and a rim diameter of 15 inches. The tire size 235/70R15 is equal to 28×9.3R15 in inches.

What Size Rim For 235/75r15?

For a 235/75R15 tire, the recommended rim size is 15 inches in diameter with a width range of 6 to 8.5 inches.

When selecting rims for your 235/75R15 tires, it is essential to choose the appropriate width to ensure proper fit and avoid issues.

Our Observation
After reviewing the differences between these two similar tire sizes, I’m struck by how marginal the performance gaps truly are. While the 235/75R15 theoretically provides more off-road clearance and cushioning, I found those advantages relatively modest.

And the 235/70R15’s handling and efficiency gains seem equally minor. Personally, I don’t think either size has a decisive performance edge for most drivers. Considering the minor variances, I recommend selecting whichever size fits your vehicle best and is most readily available.

The differences are so slight for most purposes that both tires will perform admirably. Unless you frequently drive over very rough terrain, either 235/75R15 or 235/70R15 is an excellent choice.

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