Tire Size 245/70r17 vs 245/75r17

The tire sizes 245/70R17 and 245/75R17 are very similar, but there are some key differences. The 245/75R17 tire has a higher aspect ratio, meaning the sidewall is taller.

This will give the vehicle a smoother ride and more ground clearance, but it will also reduce fuel efficiency. The 245/70R17 tire has a lower aspect ratio, which means that the sidewall is shorter. This will give the vehicle sportier handling, but it will also reduce ground clearance.

245/70r17 vs 245/75r17 Table

For a comprehensive understanding of the variances between tire sizes 245/70R17 and 245/75R17, refer to this informative comparison table.

Diameter inches30.5 (774.8)31.47 (799.3)0.96 (24.5)
Width inches9.65 (245)9.65 (245)0 (0) 0%
Circum. inches95.83 (2434.11)98.86 (2511.08)3.03 (76.97)
Sidewall Height6.75 (171.5)7.23 (183.75)0.48 (12.25)
Revolutions661.16 (410.83)640.9 (398.24)-20.27 (-12.59)

Overall Diameter
The 245/70R17 tires have a diameter of 30.5 inches (774.8mm) while the 245/75R17 tires have a slightly larger diameter of 31.47 inches (799.3mm), an increase of 3.2%. The larger diameter tires would result in a higher ground clearance for the vehicle, beneficial for off-road capabilities and poor road conditions.

However, a larger diameter could also decrease the vehicle’s acceleration performance, as it increases the distance traveled per tire revolution.

Section Width
The section width of both 245/70R17 and 245/75R17 tires is 9.65 inches (245mm). Therefore, there is no difference in this aspect. The section width is the measurement of the tire’s width from its inner sidewall to the outer sidewall. The same section width suggests both tires would offer the same level of stability and handling characteristics in terms of cornering and grip.

The 245/70R17 tire has a circumference of 95.83 inches (2434.11mm), while the 245/75R17 tire has a larger circumference of 98.86 inches (2511.08mm), representing a 3.2% increase. A larger circumference means that the tire will cover more ground in one complete revolution.

This could affect the speedometer readings, with a larger circumference tire causing the speedometer to read slower than the actual speed of the vehicle.

Sidewall Height
The 245/70R17 tires have a sidewall height of 6.75 inches (171.5mm), while the 245/75R17 tires have a taller sidewall height of 7.23 inches (183.75mm), a 7.1% increase.

The increased sidewall height of the 245/75R17 tire will generally provide a softer, more comfortable ride as the taller sidewall can better absorb bumps and potholes. However, it might also result in less stability during cornering or high-speed maneuvers.

Revolutions Per Mile
The 245/70R17 tire completes 661.16 revolutions per mile (410.83 per km), whereas the 245/75R17 tire completes 640.9 revolutions per mile (398.24 per km). This 3.1% reduction in revolutions per mile for the 245/75R17 tire would translate into slightly improved fuel efficiency, as the tire needs to rotate fewer times to cover the same distance.

Wheel Size
The wheel size, designated by the ’17’ in both 245/70R17 and 245/75R17, indicates that these tires are designed to fit on a 17-inch wheel diameter. The implication is that both tires can fit on the same rim size, allowing for relatively easy interchangeability.

Construction Type
The ‘R’ in the tire size indicates that both the 245/70R17 and 245/75R17 tires are of radial construction. This type of construction provides better heat dissipation and improved fuel efficiency compared to bias-ply tires. It also offers a softer ride and better traction.

Alternative Tire Size of 245/70r17
The overall diameter of the replacement tires should not deviate more than 3% from that of the original tires.

Tire SizeOverall DiameterDifference
275/60R1730″ (762 mm)-1.8%
235/70R1730″ (762 mm)-1.8%
255/65R1730.1″ (764 mm)-1.5%
225/75R1730.3″ (770 mm)-0.8%
285/60R1730.5″ (774 mm)-0.3%
265/65R1730.6″ (776 mm)0%
235/75R1730.9″ (784 mm)1%
255/70R1731.1″ (790 mm)1.8%
275/65R1731.1″ (790 mm)1.8%
305/60R1731.4″ (798 mm)2.8%

Alternative Tire Size of 245/75r17
The replacement tires must stay within a 3% tolerance in overall diameter compared to the original tires.

Tire SizeOverall DiameterDifference
235/75R1730.9″ (784 mm)-2%
275/65R1731.1″ (790 mm)-1.3%
255/70R1731.1″ (790 mm)-1.3%
305/60R1731.4″ (798 mm)-0.2%
285/65R1731.6″ (802 mm)0.2%
265/70R1731.7″ (804 mm)0.5%
235/80R1731.8″ (808 mm)1%
345/55R1732″ (812 mm)1.5%
255/75R1732″ (814 mm)1.8%
275/70R1732.2″ (818 mm)2.3%

Our Observation
In conclusion, the main difference between the 245/70R17 and 245/75R17 tires lies in their diameter, circumference, sidewall height, and revolutions per mile. While they share the same section width, wheel size, and construction type, the 245/75R17 tire, with its larger diameter and sidewall height, offers advantages in terms of ground clearance and ride comfort. It also requires fewer revolutions to cover the same distance, potentially providing slight gains in fuel efficiency.

On the flip side, the increased diameter could negatively affect acceleration and cause speedometer discrepancies. The taller sidewall height may compromise cornering stability. Therefore, the choice between these two tire sizes will largely depend on the specific driving conditions and requirements of the vehicle’s user.

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