37 Inch Tires on 20 Inch Rims: All You Need to Know

Using bigger tires like the 37-inch ones is very popular nowadays. They can change the look of the vehicle completely. Anyway, the compatibility of the tires with the rims must be ensured before installing them.

Compatibility is more significant if the rim is smaller. So, can you use 37 inch tires on 20 inch rims?

The answer is positive. You can use 37-inch tires on 20-inch rims. You might need to upgrade some components of your vehicle to maintain the bigger tire such as  Lifts, rings & pinions, etc.  Using 37-inch tires on 20-inch rims has both advantages and disadvantages. 

This is just the start. There are much more details available on this topic. So keep scrolling!

Can You Use 37 Inch Tires on 20 Inch Rims? 

Yes, you can use 37-inch tires on 20-inch rims. Just like the differences between 5, 6, & 8 lug Chevy rims, the properties of different-sized rims also vary. And choosing the tires for different rims depends on these properties. For example, P255/55R20, 265/50R20, 275/55R20, and 275/60R20 are the ideal tires for 20-inch rims.

However, other tires can be used with 20-inch rims too. The appropriate tire for any rim can be found by mathematical calculations. The overall diameter of the tire can be calculated using the following formula:

Overall diameter = (width in millimeters x aspect ratio / 100 x 2) + rim diameter in inches x 25.4 (to convert inches to millimeters).

Let’s find out the overall diameter of a 37-inch tire with an aspect ratio of 75% and a rim diameter of 20 inches.

Overall diameter = (950 x 75 / 100 x 2) + 20 x 25.4 = 864.25 millimeters or 34.026 inches.

We can see that a tire with a larger aspect ratio (i.e. a taller sidewall) requires a larger diameter rim to hold the overall diameter of the tire. So a 36-inch tire would require at least a rim of 17 inches for proper functioning.

Can You Use 37-inch Tires on 20-inch Rims
Source: americastire.com

As 20-inch rims are bigger than the 17-inch rims, they can maintain the 37-inch tires. For example, you can use the 318/68 R20 tires for your 20-inch rims. It will function without any issues.

Anyway, you might need some custom modifications for getting the best from the 37-inch tires. I will discuss these modifications in the next section. 

How to Fit 37-inch Tires on 20-inch Rims? 

Jeeps and all other vehicles come with specific tires from the manufacturing plant. The size of these tires is specially matched with the other features of the Jeep. So you will have to work on other features of the vehicle too while increasing the tire size.

Here are some major updates and changes that you should know before upgrading the tires. These upgrades are also necessary for using 38-inch tires on 17-inch rims.

More Lift:

Smaller tires require less lift than larger ones. For example, 33-inch and 35-inch tires require at least 1.5 inches and 2.5 inches of lift respectively. Whereas, 37-inch tires require at least 3.5 inches of lift for proper functioning. 

So if you are changing your tires to 37-inch from 33-inch or 35-inch, the vehicle lift must be increased. Or else the ride can become unstable and uncomfortable. Sometimes, controlling the car can become difficult due to less lift than required.

New Set of Ring And Pinions:

Upgrading to 37-inch tires will put more pressure on the vehicle engine. This happens due to the extra weight of the tire. The weight of the tire increases with its size. And excess weight results in an extra burden on the engine.

New Set of Ring And Pinions
Source: onallcylinders.com

The extra pressure can be handled by changing the ring and pinions of the engine. New rings and pinions will ensure a better gear ratio. A better gear ratio protects all the other parts of the engine from failing while maintaining 37-inch wheels.

Aftermarket Bumpers:

Bumpers are very necessary for the safety of the vehicle. Usually bigger bumpers provide more protection. However, the size of the bumpers depends on several factors. Such a deciding factor is the size of the tires.

Once you increase the tire size, the bumper size must be changed too. Or else it might come in the way of the tire. So you would need smaller and more compact bumpers for bigger tires. And aftermarket bumpers are a good choice for that.

Extra Cutting:

There are appropriate cuttings on the car body to give space to the tires. But this space can only provide room for factory-designed tires. The cuttings might seem smaller if you get bigger tires like 37 inches. So extra cutting might be necessary for the proper functioning of the tires.

These are the major upgrades that you need to go through for using 37-inch tires. Now let’s see some of the aftereffects of using such big tires on 20-inch rims. 

What Happens If You Use 37-inch Tires on 20-inch Rims

There are both advantages and disadvantages of using bigger tires. Have a quick look at the aspects of using 37-inch tires on 20-inch rims.

Crossing Obstacles EasilyCostlier Upgrades
More Ground ClearanceMore Pressure on The Engine
Added AestheticsExtra Fuel Burning

The table shows the basic ideas on the benefits and problems of using 37-inch tires on 20-inch rims. You should know more details about these aspects before getting the tire. So keep reading to clear all your doubts!

Benefits of Using 37-inch Tires on 20-inch Rims

There are some very useful benefits of using extra-large tires. Using 37-inch tires on 20-inch rims is no different from that. Here are some of the common benefits of this big tire.

Crossing Obstacles Easily:

Big tires like the 37-inch ones come in handy in getting over obstacles. The tire can cover more surface area because of the increased width. They provide more grip. So the car can get over medium to big obstacles pretty easily. In fact, this is one of the prime reasons for getting 37-inch tires for the vehicle.

Crossing Obstacles Easily
Source: flickr.com

More Ground Clearance:

37-inch tires also provide more ground clearance than the smaller tires. The extra ground clearance helps to absorb shocks and bumps on the road. Also, these tires provide more traction. As a result, the journey becomes more comfortable and smooth.

Added Aesthetics:

Bigger tires also add to the visual display. The 37-inch tires can change the look of the vehicle completely. The vehicle looks more rugged and big. 

These are the major benefits you will get by using 37-inch tires on 20-inch rims.

Disadvantages of Using 37-inch Tires on 20-inch Rims

Besides the advantages mentioned earlier, using 37-inch tires has some limitations too. Let’s see some of them.

Costlier Upgrades:

To make the car able to maintain the 37-inch tires it must go through some upgrades. Most of these upgrades are pricey and cost a fortune. The overall cost of the upgrades can be anywhere between $1500 to $3000. Sometimes the cost can exceed this range too.

More Stress on The Engine:

37-inch tires put more load on the engine due to the extra weight. This causes more pressure on the engine. The performance of the engine is compensated by this. Moreover, the health of the engine also deteriorates. More engine servicing might be necessary because of using 37-inch tires.

Increased Fuel Consumption:

This problem is related to the extra pressure on the engine. The vehicle engine burns more fuel because of the extra pressure. As a result, the cost of fuel increases, and using the vehicle becomes less efficient. This phenomenon is also harmful to nature as the carbon footprint increases.

You will have to face these issues while using 37-inch tires on your vehicle. Now it is your decision if handling these issues is worth it or not! Making this decision is not as complex as choosing between the 25c and 28c tires.

Frequently Asked Questions (FAQs):

What Tire Size Is 37? 

The diameter of 37-inch tires is between 92.71 to 95 centimeters. The width, height, and aspect ratios of the tire vary with models. 37X14.50-17, 385/70-16, 37X12.50-17, & 37X11.50-18 are some examples of 37 inch tires. And these tires can be used on different rims. Any rims between 15 inches to 26 inches can handle the tires. However, modifications might be necessary for the vehicle. 

What Size Tires Are Good For 20 Inch Rims?

The tire that is good for 20 inch rims is the 33-inch one. This tire makes the best combo with the 20 inch rims. Both the on-road and off-road performance of the vehicle becomes superb by using this set of tires.

Which Tire Gives A More Stable Ride?

Bigger tires give a more stable ride. Whereas, smaller tires result in a rougher ride. This is due to the increased contact area on the road. Bigger tires have more contact areas than smaller ones. They are stiffer and more stable because of this. But the price of the bigger tires is also more. 


This is all I have on 37 inch tires on 20 inch rims. I hope that now I have cleared all your doubts on this matter.

Make sure to get the upgrades for a 37-inch tire from a licensed and experienced mechanic. Or else, the vehicle might not perform according to the expectation.

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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