How do figure out what size rim you need to buy?

You get a flat tire on your trailer and it is shot. Fortuneatly you were wise enough to make sure you had a spare. You put on that spare tire on your trailer and you move on. Now you need to replace that spare tire. How do figure out what size rim you need to buy? Sure, tire size is easy, but how the heck do you figure out what rim size to get?

Like trailer tires, rims have a series of numbers which indicate their uniqueness. Here is an example of a rim size:

14x 6/4.5

The first number, 14 indicates trailer rim size (15 inches), the 5 indicates the width and the 5/4.5 indicates the bolt pattern.

For example: 205/75R14, the "14" indicates that you need a 14" rim.

Now you need to determine the width of the rim. Keep in mind trailer wheels come in a variety of widths. Normal widths for 14 inch trailer rims are 14x5.5, and 14x6. You certainly don't want the wrong rim for the wrong tire, or the tires will wear unevenly. Learn how to read the numbers and if you need help, you can always count on us!

We are your source for trailer tires, rims, and everything trailer!

Trailer Tire information

It’s a good idea to check your trailer tires on a regular basis. However, you should know that your trailer tires can appear to have a great amount of tread remaining on the tires, but the tires may still need replaced. Trailer tires are subjected to heavy loads on nearly every trip, as well as when the trailer is parked and not being used. In fact, it is better for tires to be in use on the roadways than to sit idle, becoming a victim of dry rot and other maladies. During drive time, lubricants are released from all tires. These lubricants keep the tire in good shape and extend the tire’s life expectancy. Driving also prevents the development of flat spots, which can happen when tires are idle.

One of the main causes of tire issues and failures is improper inflation. You should check the pressure of your tires when the tires are cold, or at the same temperature as the surrounding air. A great time to check tire pressure is after your trailer has been parked overnight. Tire pressure should be checked prior to every trip, as well as once a week over the course of a long journey. Always ensure that you adjust the tire pressure in accordance with the manufacturer’s specifications. This information can be found online, or on the vehicle’s Federal Certification Label or tire placard. You should also ensure that you adjust the tire pressure when your trailer is fully loaded. And never load your trailer to a weight that exceeds the vehicle’s Gross Vehicle Weight Rating (GVWR). Keep in mind that if the tires are not inflated up to the proper amounts, or if you exceed the GVWR of the trailer, the tires may be unable to carry the load properly. If tires are inflated to a pressure higher than the manufacturer’s specifications, the trailer and tow vehicle may be hard to handle and maneuver properly. Any of these scenarios can result in an accident or catastrophic damage to persons and property. If you develop any questions about tire inflation, proper loading or other issues, you can always refer to your vehicle’s owner’s manual, or speak to the dealer or manufacturer.

It’s also important to remember that tires can leak air and lose pressure during the passage of time. It’s estimated that most tires lose around one to three PSI of pressure in a single month. The reasoning behind this is that, when under pressure, molecules of air migrate from the inside to the outside of the tire. A drop in tire pressure can lead to the tire becoming overloaded which can lead to heat buildup on the tire. This can cause internal damage to the tire and lead to tire failure.

Another concern is towing a trailer at high rates of speed during hot conditions. These driving conditions significantly degrade trailer tires. The tire’s internal structure breaks down and becomes damaged during heavy driving cycles. This compromises the tire's internal and external strength, which can also lead to tire failure. In addition to proper inflation, it is recommended that you always drive at moderate speeds to keep the heat buildup as low as possible.

Unlike cars, trucks and other passenger vehicles, one should not judge the wear of a trailer tire based on tread depth alone. Experts estimate the life of a single trailer tire to be around five years during normal use and proper maintenance. After three years, it is usually time to think about replacing your trailer tires, even if the tires appear to have adequate tread. After the five year mark, most trailer tires have deteriorated such that they are worn out and need replaced. This is true even if the tires have experienced minimal use and appear to have lots of tread life left. Keep in mind that these parameters may not apply in all situations. For the best information on the life of your tires, you should have a tire expert inspect your tires and make a determination on the need for replacement.

If you need to store your trailer for a longer length of time when it won't be driven, you should ensure that the tires are inflated properly to the maximum tire pressure allowed. Tires should be stored in a garage, shed or other cool and dry area. It is also beneficial to use tire covers to further protect your tires from the effects of sun, temperature changes and other issues. You should also keep tires off the ground or floor; a barrier such as carpet or plywood will keep the tires from dry rot on the concrete or asphalt surface they are stored on. This barrier will also protect the tires from being damaged by any chemicals that are contained in the concrete or asphalt floor of the storage area.

Trailer Tire Wear Chart

Many people wonder why a trailer tire is usually more expensive than a typical economy auto tire. There are some major differences between the two.

The traction of automotive tires is required to meet all-weather standards, whereas trailer tires are not. Trailer tires only design, in reference to traction, is related to stopping suddenly.

The trailer tires are designed to reduce sway, with a stronger, harder sidewall. Should one use the automotive tires on a trailer, problems related to swaying will occur.

There are Two Basic Kinds of Trailer Tires

Bias-Ply Trailer Tires

These tires have Polyester or nylon cords that criss-cross from bead to bead. This gives the sidewalls the same ply, which makes the sidewall of the tire extremely stiff.

These cords are larger than similar passenger car tires. The larger cords reduce wear and meet the loading requirements. This allows for full resistance against sway.

These tires tend to break down rather quickly when driven long distances on highways; another issue commonly seen is called ‘cupping,’ which is an uneven wearing of the tread. This occurs because the hard sidewalls are not able to expand properly when they get hot. For this reason, bias-ply tires are usually used on a trailer that does not get a lot of use. They are ideal to use on boat or utility trailers.

Radial Tires

A radial tire has steel belts underneath the tread and can also have them in the sidewalls. Because their sidewalls are softer than the bias-ply’s, they are an excellent choice when towing for a long distance. However, the softer sidewalls will increase the chance of sway, should the trailer be improperly loaded or unbalanced.

The radial has better traction than the bias-ply tire does, which is considered irrelevant most of the time, except for a situation involving a sudden stop.
Radial tires are more expensive than the bias-ply. Both tires do carry the identical weight rating at similar load ranges.

Under-Inflation

Trailer tires should not wear out. In fact, the ‘ST’ tires, which are for trailers, contain specific chemical compounds in the rubber to resist sun and weather damage. One of the main reasons for a tire’s failure is under-inflation.

Trailer tires have been designed to supply optimal performance at their maximum inflation levels.
The stiffer sidewalls can withstand the various hazards on the road, even though the suspension on a trailer is inferior to that of a typical automobile.

A trailer tire is expected to have a lifespan anywhere from 5,000 to 12,000 miles.
Ideally, trailer tires should be replaced every three to five years. Over three years, the elements and time reduce the tire’s weight rating by about a third. For this reason, it is suggested that trailer tires be replaced every five years, despite visual appearance.

‘ST’ Trailer Tires

These tires are designed for a maximum speed of 65 MPH. As the heat begins building up on the tire, the tire begins weakening and disintegrating. Driving on a hot and weakened tire, could cause a costly blowout to occur.

‘LT’ Trailer Tires

An ‘LT’ trailer tire is not the same as a ‘Light Truck’ tire. The ‘LT’ on a trailer tire, specifies its load range.

Trailer tires are not to be used on an automobile.

Have You Thought About Your Trailer Tires Recently?

Most people follow a pretty strict routine of tire maintenance on their cars and trucks. Monthly or quarterly tasks, like checking air pressure, rotating tires, testing alignment, and monitoring tread, can all help tires perform at their best and help you identify problems. The truth is that trailer tires need regular care, too, to help your trailer perform the job it was designed to do.

Your trailer tires have a different construction than tires for your vehicle, given that they're supposed to carry heavy loads. Although you should check the tread with the penny method, replacing tires right away if the tread doesn't come to the top of Lincoln's head, there are other factors that affect trailer tire life. Tires should actually be replaced every 3 to 4 years because the materials have a limited life span and the tires can begin to develop cracks and bulges, even if their tread still looks great. Trailer tire inflation is also really important for safely transporting your loads and maintaining the tread on your tires. Always keep the tires inflated to the maximum listed pressure on the tire. remember that you should inflate to this pressure when the tires are cold, not hot. This maintenance step keeps you safe on the road and preserves the life of your tires.

Trailer Tire and Trailer Wheel Fitment Guide

You get a flat tire on your trailer and it is shot. Fortunately you were wise enough to make sure you had a spare. You put on that spare tire on your trailer and you move on. Now you need to replace that spare trailer tire. How do figure out what size rim you need to buy? Sure, the trailer tire size is easy, but how the heck do you figure out what rim size to get?
 

Like trailer tires, rims have a series of numbers which indicate their uniqueness.

Here is an example of a trailer rim siz

e:

14 x 6   5/ 4.50

 

The first number, 14 indicates trailer rim size (14 inches), the 6 indicates the width and the 5/4.50 indicates the bolt pattern.
 

For example:

205/75R14

The "14" indicates that you need a 14" rim.

Now you need to determine the width of the rim. Keep in mind trailer wheels come in a variety of widths. Normal widths for 14 inch trailer rims are 14x5.5, and 14x6. You certainly don't want the wrong rim for the wrong tire, or the tires will wear unevenly. Learn how to read the numbers and if you need help, you can always count on us!

 

We are your source for trailer tires, rims, and everything trailer! Shop now at www.TrailerandTruckParts.com.

8 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
8x3.75	4.80x8
8x3.75	5.70x8
8x5.375	165/65-8
8x5.375	16.5x6.50-8
8x7	215/60-8
8x7	18.5x8.50-8

10 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
10x6, 10x7	205/65-10
10x6, 10x7	20.5X8.00-10

12 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
12x4, 12x4.5	4.80x12
12x4, 12x4.5	5.30x12
12x4, 12x4.5	ST145R12

13 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
13x4.5	ST155/80D13
13x4.5	165R13
13x4.5, 13x5	ST175/80D13
13x4.5, 13x5	ST175/80R13
13x4.5, 13x5	ST185/80D13

14 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
14x5.5, 14x6	ST195/75D14
14x5.5, 14x6	ST205/75D14
14x5.5, 14x6	ST205/75R14
14x5.5, 14x6	ST215/75D14
14x5.5, 14x6	ST215/75R14

15 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
15x5, 15x6	ST205/75D15
15x5, 15x6	ST205/75R15
15x6, 15x7	ST225/75D15

16 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
16x6, 16x6.5, 16x7	LT 7.50x16
16x6, 16x6.5, 16x7	ST235/80R16
16x6, 16x6.5, 16x7	ST235/85R16

17.5 inch Trailer Wheels with the correct fitting Trailer Tires

Trailer Wheel Size	Trailer Tire Size
17.5 x 6.75	ST215/75R17.5

Which Load Range do I choose for my Trailer Tire?

Q:

I’ve noticed that the tires available on your web site have a B, C or D rating but I do not know what the current, and original, rating is of tires are that are on the trailer, only the size. Please advise how I should determine the best tire for my trailer.

A:

The load range refers to the load rating of the trailer tire. The higher the letter =  higher the load capacity. And usually more costly, as well.

Example:

Load range B is a 4 ply tire rated at 1,045

Load range C is a 6 ply tire rated at 1,120

Load range D is a 8 ply tire rated at 1,200

To help you determine which trailer tire load range you need, please read the following; Lets assume you have a single axle trailer, two tires (LR C). You would multiply the load capacity times two. 1,120 x 2 = 2240 lb you can haul on the trailer tires.

Please note, you must take your axle capacity into account as well. If you have a 2000 lb axle you should match your tires to the axle rating. Therefore a LR B (1045 x 2 = 2090 lb) would be sufficient and more economical as well.

That means the weight of the trailer, plus the weight of the load, is what your trailer tires and axle are rated to haul. Another example would be, if your axle is rated at 2,000 lb and your trailer weighs 600 lb, you would only be able to haul up to an additional 1400 lb.

Trailer Tires: Radial or Bias Ply?

Trailer tires should be replaced as soon as they begin to show wear and tear or about every four years, whichever comes first. If the tires on your boat trailer have a series of small cracks around the circumference of the tires, it may be due to dry rot, which can cause the tire to blow unexpectedly, resulting in being stuck on the side of the road as well as expensive repairs and towing fees.

It is important to buy only tires that are designed for use on a trailer. Trailers do not steer the same as a truck does and trailer tires are designed to account for the difference in steering, use in water and dry land as well as heavy loads on the trailer. There are basically two types of tires for a trailer:

· Radial trailer tires are durable, provide good traction, have less rolling resistance and improved stability.

· Bias Ply trailer tires are designed for extreme locations and driving conditions. These tires are made for excellent traction on all terrains including sand, gravel, snow and mud. However, non-radial bias ply tires only have a small amount of shock absorption, so they can be a bumpy ride.

Trailer tires with the largest diameter typically produce the least RPMs, which will make the tire more resistant to damage. It is recommended that you choose tires with a significant number of plies because they will make the tire more stable and longer lasting. It is important to choose the correct load rating for your trailer. The load rating can usually be found on a placard which is usually found towards the front of the trailer.

ST Trailer Tires vs. Passenger Tires

ST Trailer Tire Characteristics

ST trailer tires are made to support large loads. Their polyester cords are larger than those of other kinds of trailer tires. They are also stronger and more weather resistant. These tires have a maximum speed rating of 65 MPH and a life expectancy of 3 to 5 years.

ST Trailer Tires Differ Greatly from Passenger Tires

Special Trailer Service Tires or ST tires have been specifically designed and engineered for trailers and RV’s. These tires are constructed especially to carry heavy loads and to be pulled. Passenger tires are designed for traction. Traction moves your vehicle on the road allowing you to make turns. It also enables your vehicle to pull a trailer. Adding flex to the sidewall of tires makes a tire capable of ride and handling. Increased traction gives the driver better control while driving. Only trailers that have brakes have any need for traction.

Tires are specifically designed for certain weights. Passenger tires are rated to carry much lower weights then ST Trailer tires. It is always best to use tires appropriate for a vehicle and its payload.

Making the Right ST Trailer Tire Choice

Always purchase new ST Trailer tires. Used tires are not safe. Checking reviews will help you make a good choice. Radial tires are better because they are more fuel efficient, have low friction and are not affected by weather.