Difference Between 37 vs 38 Inch Tires – Is Bigger Size Better!

Car aficionados have made it a habit to change their tires regularly. This is for very good reasons. Many people use it to improve the appearance and performance of their cars. Other people do it to save money because they drive on challenging roads or bad weather.

If you need to replace your car tires, you may be undecided about going with 37-inch or 38-inch tires. In this guide, we’ll walk you through a comparison of these two tires so you can pick the one that’s right for you.

Big Difference Between 37 Vs 38 Tires

Based on their capabilities, both tire sizes will give optimal performance. For example, 37-inch tires are the perfect size for a good off-road experience. Because of their bigger size, they will be better able to roll over large rocks, logs, and other off-road obstacles. Furthermore, a 37-inch tire can maintain its pace better than smaller tires, helping you maintain the necessary momentum for conquering larger obstacles ahead. This size is also ideal for bogging because these tires will keep your chassis clear of any road debris and deep mud.

The 38-inch tires, on the other hand, are what most impressive off-road trucks require to roll over any terrain. These tires will provide you with a lot of road consistency and are ideal for off-roading. Below are the noticeable features that

Differentiate the 37 and 40-inch tires

Features37-Inch Tires38-Inch Tires
Tire diameter37 inches38 inches
Section width11.5-14.5 inches12.5-15.5 inches
Average weight68-85 pounds81-95 pounds
Rim size15-26 inches15-22 inches
Tread depthMostly 22 32ndsMostly 21 32nds
Load index rating121-125121-126
Load capacity3500-40003400-4300
Tire aspect ratio12.5-80Mostly 13.5
Maximum air pressure45-65 psi45-65 psi
Speed ratingQQ
Revolution per mile560-600540-580
StyleAll-terrain, mud terrainAll-terrain, mud terrain
PriceMostly below $800$400 to above $1000
Top 3 brandsFirestone Destination M/T2 Cooper Discover SST ProBaja Boss, Nitto, Open Country M/T

37-Inch Tires

Tread Design

Since many people prefer to use these tires off-road, their tread design is more robust and durable. Therefore, you can easily use them and expect an outstanding grip on any terrain.


Radial construction is used in these tires. As a result, the tires are more flexible, giving you a more comfortable ride.

Rim Diameter

These tires can be used with 15 to 26 inches wide rims.

Aspect Ratio

These tires have an aspect ratio of up to 80.

Tire Width

These tires are wide, ranging from 11.5 to 14.5 inches. Because of their huge width, they have more ground contact, making your vehicle easier to handle.


  • It can be used both on-road and off-road
  • Looks good
  • Comparatively inexpensive
  • Highly durable


  • Too huge, hence it is hard to fit a spare tire under the truck
  • Heavy

38-Inch Tires

Tread Design

These tires have a durable tread pattern. This tread gives the tires the capacity to grip the road, improving the traction.


The tires feature the new radial construction that makes them suitable for all roads and terrains.

Rim Diameter

The tires can be used with 15 to 22 inches wide rims.

Aspect ratio

The aspect ratio of these tires is mostly 13.5.

Tire Width

The width of these tires’ ranges from 12.5 to 15.5 inches. This wide width provides greater ground contact, which improves the handling.


  • Highly durable
  • Smooth riding and flexibility
  • Looks good


  • Heavy
  • Too large

Common Tire Sizes

Common 37 Inch Tire Sizes

20 Inch Rim – 37×12.5R20, 37×13.5R20

18 Inch Rim- 37×12.5R18, 37×13.5R18

Common 38 Inch Tire Sizes

18 Inch Rim- 38×15.5R18, 38.5×14.5R18

20 Inch Rim – 38×13.5R20 , 38×15. 5R20 , 38.5×14.5R20

So, Which One is Better: 37 Or 38 Tires?

We’re comparing 37-inch vs 38-inch tires. This category contains several items. 37-inch all-terrain tires like the Wild-peak A/T3W and Grabber A/TX tires are recommended for driving in dry, wet, and snowy conditions. Before traveling through muddy places, you might want to purchase 37-inch mud tires like the Discover SST Pro mud tires.

38-inch all-terrain and mud tires will be a wise choice if you’re looking for tires to use in all seasons. The 38-inch all-terrain tires are also suitable if you love driving through rocky areas.

Don’t Buy 37” Tires! Must Watch First

Frequently Asked Questions (FAQ)

Do Larger Tires Have an Impact on the Speedometer?

The accuracy of your speedometer will be affected if you customize your car with huge tires. This is because part of the readout on your speedometer is determined by the revolution of the tires, which is based on the circumference of the tires. If your speedometer is not re-calibrated to the new tires’ greater circumference after they are installed, it will not reflect the correct speed. To compensate for the change in tire size, you’ll need a professional to either adjust the speedometer gear or reprogram your vehicle’s computer.

Do Bigger Tires Have an Impact on the MPG?

Installing larger tires on your vehicle will have a significant impact on your car’s average miles per gallon (MPG). Larger tires will reduce your fuel economy for a variety of reasons.

First, larger tires are typically heavier. A set of four large, heavy tires can add a significant amount of weight to your car. Your car’s acceleration will suffer due to the extra weight, and it will use more fuel. It may also put greater strain on your brakes as you try to slow down.

Second, bigger tires may protrude from the wheel rather than align with your SUV or truck. This can reduce your car’s aerodynamics and raise its fuel consumption.

Finally, wider tires have a bigger contact patch with the road, which can cause rolling resistance to increase.

Can Installing Big Tires Void Your Warranty?

Some manufacturers will expressly advise against increasing the size of your vehicle’s tires. Additionally, certain manufacturers will void your warranty if you want to change your vehicle’s suspension with wider tires and lift kits.

Are Heavy Tires Better Than Lighter Tires?

Both tires may be worse or better, depending on various factors. For example, heavier tires can carry more weight than lighter tires. On the other hand, more lightweight tires are frequently easier to change and install.

How Do You Know What Type Of Tires You Need?

The type of tire you’ll need is mostly determined by the weather and terrain you’ll be driving on.


We hope this article has provided you with all of the information you require regarding 37 vs 38-inch tires. However, determining which is better than the other is a matter of personal preference and taste.

Abdullah Anas

I am Abdullah Anas, a tire expert. I hate seeing people struggle to find the right tires for their cars. That is why he puts much effort into writing well-researched content about car tires. Today, it’s six years since he started the good work. I have received a lot of positive feedback from his readers and friends. Now my target is to let you understand every detail about all the tires available in the market

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