Tire pressure and load range? (Suits you)

1845 lbs. Note: 35 psi is the assigned ‘maximum load’ pressure for standard load tires and 41 psi is the assigned ‘maximum load’ pressure for extra load tires.

Maximum Load.

Euro-Metric Passenger Vehicle Tires
Load Ranges Abbreviated Max Load Pressure
Standard Load (SL) 36 psi (250 kPa)
Extra Load** (RF) or (XL) 42 psi (290 kPa)

1

What PSI should I run in my 10 ply tires?

Don’t run 50, 35 to 38 is about right. If you run 50, you’ll be one of those talking about how terrible 10 ply tires are on a truck.

Should I increase tire pressure for a heavy load?

An increased pressure reading (typically 2 to 6 psi higher ) is normal when tires are hot. If recommended by the vehicle manufacturer, increase tire pressures for towing, carrying heavy loads, or extended highway travel.

Is 40 psi too high for truck tires?

Normal tire pressure is usually between 32~40 psi(pounds per square inch) when they are cold. So make sure you check your tire pressure after a long stay and usually, you can do it in the early morning.

Should I run my truck tires at max psi?

In most of these cases, 40 psi should be more than enough, and since most modern tire designs will allow up to 44 psi (in some cases more) this is not a problem. If you have a heavily loaded vehicle, up to 44 or even higher is ok if the tire allows it, but this is a little high for most vehicles.

How many times a month should you check your tire pressure?

Still, the recommendation for checking tire pressure is still once a month. A good rule of thumb to remember is that your tires lose about one PSI every month after you fill them, so checking every month can help you to ensure that they are always inflated to the proper pressure.

Why do mechanics over inflate my tires?

The short answer is that when they service and change your oil the tires are generally hot. The PSI in your door is for cold (car has sat overnight). If your tires are hot the pressure will be higher than cold. Thus when they fill the tires they do so to the appropriate “hot” level.

Is it better to have over inflated or under inflated tires?

Underinflated tires are the more dangerous of the two. Over-inflation may not sound harmful, but it can definitely cause increased wear and tear on tires. An overinflated tire is much stiffer and does not bend as much as it should, reducing the amount of the tire that can contact the road.

At what PSI will a tire explode?

Under hot weather and highway conditions, the temperature of the air inside the tire rises about 50 degrees. That increases the pressure inside the tire about 5 psi. The burst pressure of a tire is about 200 psi.

What should tire pressure be in hot weather?

If tires are warm from being driven, set pressures 4 psi above recommended in the morning and 6 psi if checked and set in the afternoon.

Is 50 psi too much?

50 PSI might be ideal for medium truck tires, but is too high for a typical car tire, bicycles and motorcycles will take high twenties to low thirties, tractor trailers can approach 100 PSI.

Should all 4 tires be the same PSI?

The manufacturer’s recommendation (Usually on a decal on the door pillar) is the ideal pressure for a compromise between handling, ride comfort, noise and tire wear and they do not always recommend the same pressure on all tires of a car.

Is 35 tire pressure too high?

Higher pressure generally is not dangerous, as long as you stay well below the “maximum inflation pressure.” That number is listed on each sidewall, and is much higher than your “recommended tire pressure” of 33 psi, Gary. So, in your case, I’d recommend that you put 35 or 36 psi in the tires and just leave it there.

How much psi should I put in my truck tires?

Air pressure in tires is measured in pounds per square inch, or PSI; usually, the recommended pressure ranges between 30 and 35 PSI.

Tire pressure and load range

The appropriate tire pressure and load range for your vehicle are specified on a placard located in the driver’s door area of the vehicle. However, the suggested tire pressure is for the tires that came with the vehicle. In the event that you switch to a different size tire that is within the same load range, you must maintain the appropriate pressure shown on the placard. However, if you want to switch to a different load range tire, refer to the tables below.

How to find the tire’s load range

On the sidewall of the tire, you’ll find the load range of the tire indicated as a letter after the tire size indications.

Passenger tire load range designations and pressures

Most passenger tires on sedans, coupes, crossovers, and minivans do not have load ranges labeled since they are constructed with a normal 4-ply rating and are not intended to handle heavier weights. However, if the load rating of the passenger tire is indicated, it will be either SL for Standard Load or XL or Reinforced for Extra Load, depending on the manufacturer. While an SL tire can withstand a maximum payload of 36 psi, an XL tire can withstand a maximum payload of 42 psi when the vehicle is loaded to its full capacity.

In contrast, if you put P-metric passenger tires on a light vehicle or SUV, you must lower the weight-carrying capability of the tire to 91 percent of the load range listed on its sidewall.

More about load range and maximum pressure

It is recommended that you pump your tires to the maximum pressure given in the tables above if you intend to transport the maximum payload in your vehicle. Consider this: If the maximum load rating for a P235/75R15 SL rated tire is 2028 pounds, you should inflate the tire to its maximum pressure of 35 pounds per square inch (psi). Whenever you inflate to a lower pressure, you must increase or decrease the maximum load in proportion (example: at 32-psi. the maximum load must be reduced to 1940-lbs and 1852-lbs at 28-psi.)

Maximum load pressure is NOT the same as the tire’s maximum inflation pressure shown on the sidewall

For passenger tires, the maximum inflation pressure shown on the tire’s sidewall is typically between 44 and 51 psi, depending on the model. In terms of tire structural integrity, the maximum inflation pressure has absolutely nothing to do with it. It will not explode if you inflate it to 1 psi above the maximum pressure specified. However, inflating the car to its maximum inflation pressure will have an effect on other components of the vehicle. When you inflate your tires to their maximum inflation pressure, the size of the contact patch (the amount of the tire tread that comes into touch with the road) is greatly reduced.

Over inflating a tire for better fuel economy

Passenger tires typically have a maximum inflation pressure of 44 to 51 psi, which is indicated on the tire’s sidewall. The maximum inflation pressure of the tire has absolutely nothing to do with the structural integrity of the tire itself. Adding one psi to the indicated limit will not result in an explosion. The vehicle’s performance would be adversely affected if the maximum inflation pressure is reached.

Increased inflation pressure results in a considerable reduction in the size of the contact patch (the section of the tire tread that makes contact with the road). As a result, the ride quality, the passenger comfort, and the wear characteristics of the tire will all be negatively affected.

North American Load & Pressure Markings

It is mandatory for tires sold in North America to have the maximum load and maximum inflation pressure printed on the sidewall of the tire. In most cases, tire pressure is expressed in ‘pounds per square inch’ (psi), Kilopascals (kPa), or bars of pressure (bars) (bars). Located at sea level, the Earth’s atmosphere exerts a force of one kilogram per square centimeter against the surface of the planet. One bar of pressure is equivalent to 100 Kilopascals or 14.7 pounds per square inch of pressure, and one bar is denoted by the symbol ‘bar.’ Take note that 1 psi Equals 6.895 kPaA.

The tire’s maximum tire inflation pressure is 300 kPa, and this is also shown on the label (44 psi).

In order to calculate the maximum load that a tire is rated to bear, the tire pressures that are employed are determined by the sizing system industry standards that are applied to the tire.

Sizing System Tire Load Range Load Pressure
P-metric Light LoadStandard LoadExtra Load 35 psi35 psi41 psi
Euro-metric StandardReinforced or Extra Load 36 psi42 psi

However, the maximum inflation pressure of the tire may be higher, such as 300 kPa (44 psi) in this example or even 350 kPa (50 psi) in some cases (51 psi). Specifically, this is done to satisfy a car manufacturer’s wish to tailor the tires’ high-speed performance, handling characteristics, and/or rolling resistance to better suit the vehicle. In order to determine the appropriate tire pressures for their vehicle’s driving circumstances, it is critical that owners reference their vehicle’s tire information placard (which is normally located on the driver’s door or doorjamb) or their owner’s handbook.

It’s time to rethink standard 100-psi tire pressures

Tire inflation pressure is a conversation-killer at a party, but it’s something fleets should be discussing with their tire vendors, shop workers, and drivers on a regular basis. Evidence reveals that using a 100 psi inflation pressure that is set and forget, works in all positions, and is one-size-fits-all is not the greatest strategy to optimize tire value. Although the number is simple to remember, you may be losing miles-per-32nd in the name of ease. It is important to maintain proper tire inflation pressure since it has an impact on the footprint of the tire, traction, and tire life.

  1. (Photo courtesy of Jim Park) When it comes to longhaul Canada-U.S.
  2. Both fleets operate at an 80,000 lb.
  3. They claim that the tires had ran out of gas between 400,000 and 500,000 kilometers before falling off the vehicle, according to them.
  4. How does one get a set of drive tires to last for more than half a million kilometers on a single charge?
  5. His fleet gets between 500,000 and 575,000 kilometers out of its drive tires.
  6. There is no use of a tire pressure monitoring system or automated tire inflation in this experiment.
  7. The most effective thing you can do to avoid erratic tire wear is to equalize the pressure between twin tires.
  8. Even a 5-psi variation in pressure may have a significant effect.
  9. The same is true for Brad Summers, the shop manager of Liberty Linehaul, located in Ayr, Ontario.
  10. He claims that the footprint or contact patch of the tire is everything.
  11. The footprint gets rounded on the sides, as well as the front and back, if the tire is overinflated.

Additionally, you will have less traction since the part of the tire in contact with the road will be smaller, which is especially important when the vehicle is lightly laden.’ Summers’ fleet has a target tire life of 450,000 to 500,000 kilometers, and he seldom encounters tires that perform below that standard.

He, too, discusses extensively with his tire provider, and the two of them have come up with the optimal tire pressure of 90 psi.

‘That information is in the possession of the tire companies.

Inflating drive and trailer tires too high or too low has its disadvantages, and the opposite is true as well.

Most steer tires are underinflated at 100 psi, with some being severely underinflated. Check your steer axle weight to determine the real tire weights on your vehicle, and then inflate the tires to match. (Photo courtesy of Jim Park)

80, 90 or 100 psi?

To comprehend inflation pressure, you must first realize that it is not the tire itself that is responsible for supporting the weight, but rather the air contained within the tire. The higher the tire pressure, the greater the amount of weight that the tire can hold. It is also important to consider the amount of air in the tire. Tires having a bigger internal capacity may withstand heavier loads while maintaining the same pressures. A typical 11R24.5 tire at 90 psi can support up to 5,840 lb, according to the load and inflation data provided by Continental Tire.

  • According to the same data, an 11R22.5 tire inflated to 100 psi and used in a dual configuration can hold 5,625 lb.
  • In the United States, where the maximum legal axle group load is 34,000 lb, the maximum load on any one of the eight tires in the tandem group would be just 4,250 lb.
  • Generally speaking, single tire loads in dual configuration will not surpass 4,690 lb in the majority of Canada, while the tandem group weight maximum is 17,000 kg (37,500 lb).
  • It is estimated that the minimum pressure necessary to support those tire loads on 11R22.5 tires in both the United States and Canada is 70 pounds per square inch.
  • The papers are technical documents that describe the minimum inflation pressure necessary to support a specific load.
  • However, the information may be presented in a somewhat different manner.
  • Choosing the inflation pressure to employ is entirely up to the user, provided that it fulfills or exceeds the minimal requirements.
  • Inflation pressure can have an impact on the size and shape of the tire’s contact patch, even though it isn’t as big of a problem as it used to be (and this does vary across different tire types and models).
  • In some cases, over-inflated tires might have a narrower contact patch that is rounded at the front and rear, indicating that there is less rubber in touch with the surface.
  • Edge wear can become more severe, and traction might be impaired, especially when the vehicle is lightly loaded.
  • Our recommendation is that you keep your tire pressures below 100 psi, but anything less than that may result in extended tire life and happier drivers owing to improvements in the overall ride quality of the vehicle.
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The findings were excellent in terms of ride quality and tire wear, but they were continually redirected back to the scales because the inspectors noticed higher-than-normal sidewall deflection and assumed the tires were ‘run-flats.’ Make contact with your tire provider to discuss inflation pressure if any of the information above resonates with you.

Inform them that you would like to examine test results, footprint charts, and so forth.

When it comes to fuel efficiency, running over-inflated tires may result in marginal benefits of 1-1.5 percent, according to some estimates.

Have that discussion with your tire provider, but don’t invite anybody else.— The name of Brad Summers, the shop manager of Liberty Linehaul, has been corrected in this story to reflect the right spelling. Today’s Trucking sincerely apologizes for the mistake.

Tires and Air Pressure –An Off-Roading Match Made in Heaven!

Taking the time to air down your tires before hitting the trails in your off-road truck may be useful, as it will provide you more grip on various terrains. The question is, how far should you go in order to save face? As a result, there is no one size fits all solution since too little air pressure can actually make traction worse on some surfaces, just as too much might do the same on others. You also need to consider your tires and wheels and what they’re capable of before letting air out of them indiscriminately, or else anything, such as your off-road vehicle or Jeep, might be ruined.

These suggestions on wheels, tires, and lowering pressure should at the very least assist you in understanding what is occurring while you air down your vehicle and what you should expect or avoid!

Tire Construction Is Important

Safely inflating down a tire before going off-roading necessitates the use of a tire that is capable of withstanding the added stress that airing down places on the sidewalls, which can become a weak point in the tire. If you drive with low air pressure, your tires will have to hold a greater amount of vehicle weight, therefore it’s important to know how much weight your tires can handle before you start letting the air out of your tires. Tires with greater load ranges, often Load Range E tires, are the greatest choice for off-road use because they are constructed with stronger, more durable sidewalls that can withstand airing down, allowing you to get additional traction while minimizing the chance of destroying the sidewall.

Wheel Specifics Matter

When it comes to lowering your air pressure, the diameter and breadth of your wheels will be important considerations. Generally speaking, the greater the diameter of the wheel, the narrower the sidewall of the tire that is used to accommodate the larger diameter. If you want to use larger wheels while simultaneously keeping the air pressure in your off-roader low when hitting the trails, it’s critical that you pair your larger diameter wheels with larger tires that have taller sidewalls. When it comes to wheel width, the breadth of the wheel and tire indicates that the contact patch is bigger, which translates into higher grip on slippery surfaces.

Know Your Vehicle’s Weight

How far are you willing to go? A great deal of this will be determined by the weight of your car as well as the tires and wheels you choose to put on it. Keep in mind that the heavier the car, the greater the likelihood that your rim will ride on the tire and cause a pinch flat; conversely, the lighter the vehicle, the better your chances of achieving desired outcomes by airing down as low as you possibly can without risking a pinch flat.

Make little adjustments at a time, and make certain that the tires on your larger equipment do not have their air pressure lowered to the point where they wind up destroying the tire and rims.

When to Air Down Going Off-Road

Which of the following are the optimum times to air down your tires, keeping in mind the nuances of how your wheels, tires, and vehicle all influence judgments concerning tire pressure? For the most part, it’s used whenever you need greater traction. Overall, it’s a good idea to pump down your tires a few PSI before hitting the trail in order to soften the tread a little bit and improve traction; but, there will be moments when you’ll want more air pressure than that. Increase the air pressure in your tires for an even softer tread for rock crawling, which will help your tires grasp uneven terrain while the wheel is rotating.

When driving on softer or wet conditions such as snow, sand, or mud, the idea is to produce a flatter, broader contact patch in order to provide you with that extra traction you require.

Just make sure you don’t drop your pressure all at once without first checking it out with your off-road trucks to prevent driving on flat tires.

Take Care When You Air Down for Better Traction

When traveling off-road, letting some air out of your tires is one of the most effective methods to enhance grip. Don’t just air down your car without thinking about why you’re doing it or how much you should start with; you need to add up all of the components you’re dealing with in order to get an accurate pressure level estimate. Testing and experimenting until you get satisfactory results without causing damage to your wheels, tires, or even your off-road truck is the name of the game!

New Red Steel Bumpers – An Affordable Choice!

Load ratings and tire sizes are important to understand when it comes to truck tires. The alpha-numeric code on the side of your vehicle’s tire specifications contains more information than you think about the tires on your truck. Become familiar with the letters and figures that represent the truck load index, speed rating, and size of your tires and how to interpret them. When it comes to selecting tires for your vehicle, understanding these values can help you make better decisions. Please visit this page to examine all of Reading’s truck bodies if you need assistance in determining which truck body is best for your requirements.

How to Read Tire Specs

If you look closely at a tire, you will see that it contains a significant amount of information. The sidewall of the tire contains information ranging from the manufacturer’s name to the tire size and load rating. Understanding how to interpret these statistics necessitates familiarity with the values to search for and the meanings of those values. The kind of tire, the width, the aspect ratio, the construction, the wheel rating, the load index, and the speed rating are all listed on the sidewall.

  • The Tire and Rim Association establishes standards for these parameters that are followed by all American tire manufacturers.
  • In rainy situations, AA traction grades perform the best, while the performance of the other classes decreases — AA, A, B, and C.
  • Those with an A rating operate admirably at speeds in excess of 115 mph.
  • When looking for the first section, search for a string of letters and numbers that may begin with the letters P, LT, or no letter at all.
  • This alpha-numeric code contains a great deal of information from the manufacturer, including the tire type, width, aspect ratio, construction, and tire diameter.

If you want to get the most out of this information, you must first grasp what the tire size information, together with the load ratings and speed information, means.

Truck Tire Sizes Explained

The tire size is normally denoted by a letter denoting the kind of tire and a two-digit number indicating the rim size at the end of the tire size. You will find extra information on the tire size and structure in the space between these two sections.

1. Tire Type

In the first letter, you will see the type of vehicle on which you should install the tire. It is denoted by the letter P for a passenger car or light-duty truck. In general, these tires have lower pressure requirements than other types of tires. The letters LT stand for light-duty truck, yet these are frequently seen alongside bigger 3/4- and one-ton trucks. Unless there is a letter at the beginning of the tire name, the tire is a Euro-Metric tire, which is often seen on passenger vehicles. In the example P235/75R15, the letter P indicates that this tire is designed to fit onto a passenger vehicle.

2. Sidewall Width

Check the three numbers after the letter, or the first three digits in front of a slash mark if your tire does not have a letter at the beginning of the tread pattern. Using these data, you may find out how wide the tire is from sidewall to sidewall, measured in millimeters. Regardless of whatever business manufactures the tires, the metric standard is used for the majority of tire measurements. P235/75R15 is an example of a tire with a width of 235 millimeters between the sidewalls.

3. Aspect Ratio

Immediately below the slash mark, you will notice a two-digit number. This number relates to the aspect ratio of the sidewall, which is the proportion of the height of the sidewall to the width of the sidewall. The aspect ratio is represented by the number 75 in the sample tire, P235/75R15. In this tire, the height of the sidewalls is approximately 75% of the whole width of the sidewall.

4. Tire Construction

Following the aspect ratio, you will notice one of three letters — R, B, or D — that represent the resolution. The information in this letter pertains to the tire’s construction. Radial tires, denoted by the letter R, have their internal cords set at 90-degree angles to the tire’s centerline, as opposed to bias tires. Bias-ply tires feature a D in this place to denote that they are designed in a diagonal manner. The cables that cross each other on these sorts of tires are at 30 to 45-degree angles.

Radial tires, which are more comfortable and last longer, have mostly replaced them.

These tires combine the diagonal pattern of bias-ply with the addition of belts inside the structure for a unique look.

In the case of the example given, P235/75R15, the R indicates that it is constructed in a radial fashion.

5. Wheel Diameter

However, while the sidewall width is measured in millimeters, the wheel diameter, which is the final digits following the construction letter, is measured in inches. When you see a large number here, it indicates a greater wheel size. If you decide to replace your rims, you will also need to replace the tires in order for them to fit properly.

When changing wheel sizes, exercise caution because bigger wheels have an impact on the handling of the vehicle. P235/75R15, for instance, has a 15 at the end of the tire’s name, indicating that it must be mounted on a 15-inch diameter wheel.

6. Load Index and Speed Rating

It is followed by two digits and a letter, which correspond to the size information. The weight rating of the tire is represented by the numbers, while the speed rating is represented by the letter. If we take the tire size P215/65R15 85H as an example, the 85 represents the load index, commonly known as the tire ply rating, and the H represents the speed rating, which indicates the maximum speed at which the tires should be operated. The speed ranges from 3 mph to 186 mph in this case.

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What Is a Truck Tire Load Range, Ply Rating, Tire Load Index and Tire Speed Rating?

Following the tire size, you will frequently find a number and letter combination. The tire load and speed rating are both shown by this set of facts. Some tires may have three letters instead of one on the sidewall. The first number indicates the speed rating, while the next two numbers indicate the load range. Tire Load Range and Tire Ply Rating are two important factors to consider. The phrase ‘ply rating’ refers to the number of ply layers in a tire’s load range, which dates back to the days of bias-ply tires, which had varying numbers of ply layers.

  1. Today, ply rating still relates to the strength of a tire, but because fewer, stronger plies are utilized, the numbers have been replaced by letters denoting the load range of the tire.
  2. The load range specifies the maximum weight that the tire is capable of supporting in pounds.
  3. It represents the greatest amount of pressure that the tire can withstand when carrying its maximum load.
  4. Light truck load ranges are denoted by the letters B, C, D, E, and F, and they have rising maximum pressures as they progress through the alphabet.
  5. Tires with load ranges of D, E, and F have pressures that climb in 15-psi increments starting at 65 psi, 80 psi, and 95 psi, respectively.
  6. Commercial vehicles, which have substantially larger carrying capacities, are classified according to their load ranges, which are F through L.
  7. They both have the same amount of plies, but the numerals on the side indicate that they can withstand different maximum pressures.
  8. Instead, the load ratings on these LT tires are equivalent to those of dual tires.
  9. The second number indicates how much weight the tire can bear when mounted on a tandem axle.

When two tires are paired together, the second number is frequently lower than the first because of uneven load distribution. However, when the tire is functioning on its own, it has the ability to support a greater amount of weight.

When a tire is inflated to the required pressure, the load index on the tire provides a numerical figure indicating the maximum weight that the tire can support. In general, higher numbers indicate a tire’s capacity to withstand bigger loads. They begin at 1, which can support 102 pounds, and progress up to 150, which can support 7,385 pounds of weight in total. In the case of the tire P215/65R15 85H, the load index of 85 indicates that the tire can carry up to 1,135 pounds. The load index is similar to vehicle tire load ratings in that the higher the index, the more resistant the tire is.

It’s crucial to note, however, that no matter how sturdy the tire is, you should never carry weights that are larger than your tires or vehicle’s suspension are designed to support.

3. Tire Speed Rating

To keep your truck and cargo safe, you must also be aware of the speed ratings. This will prevent your tires from being damaged and your vehicle from being damaged. Tires have load indices to limit the amount of weight they can bear, and they also have speed ratings to determine their maximum speeds. The majority of speed ratings on tires in the United States exceed the speed restrictions on highways. You should never drive faster than the official speed limit, regardless of how capable your tires are.

A designation follows the load index number and before the load range letter, if one is present, to indicate the speed rating.

These should only be used for off-road trucks that are unable to attain high speeds owing to the harsh terrain.

See the following table for the speed ratings of various tires and the standard cars that they are designed for:

  • L:Only use these tires on off-road trucks that will not go faster than 75 miles per hour
  • M: Do not exceed 81 mph while operating with temporary spare tires. N:These tires have a top speed of 87 miles per hour
  • P: Tires with a P grade are not capable of speeds more than 93 mph. q:Q tires are often winter studded or studless tires, and they should not be driven faster than 99 miles per hour. Heavy-duty LT trucks may have a R rating, which denotes a maximum speed restriction of 106 miles per hour
  • R: S:Family vans and sedans with a maximum speed of 112 miles per hour are designated with the letter S. T:Family sedans and vans may also be equipped with T-rated tires, which are capable of reaching speeds of up to 116 mph. U:U tires have a top speed of 124 miles per hour
  • H:Sports cars with H speed classifications may reach speeds of up to 130 miles per hour. V-rated tires are commonly seen on sports vehicles, sedans, and coupes, and they have speed ratings of up to 149 mph. W: Exotic sports vehicles have tires that are capable of reaching speeds of up to 168 mph and are designated with the letter W. Y: The fastest speed rating is now Y, rather than Z, which previously indicated a speed greater than 149 mph. This permits the tires to achieve 186 mph.

These tires should only be used on off-road trucks that will not go faster than 75 mph. L: M:Do not exceed 81 mph while driving with temporary spare tires. N:The top speed of these tires is 87 miles per hour. If your tires have a P rating, they can only go up to 93 miles per hour; In most cases, Q tires are either winter studded or studless tires, and their top speed should not be more than 99 mph. Heavy-duty LT trucks may have a R rating, which denotes a maximum speed restriction of 106 miles per hour.

United Tires can go up to 124 miles per hour on their U:U tires.

v: In order to attain speeds of up to 168 mph, exotic sports vehicles utilize tires with the letter W on them.

Previously, the fastest speed rating was Z, which indicated speeds greater than 149 miles per hour.

Truck Use and Add-Ons

When installing tires on your truck, make sure you use the tire sizes and load ratings that the manufacturer has advised. However, if you alter your vehicle by adding service bodies, platforms, tow hooks, or other features, the size and strength of the tires you require for your vehicle will change. Consult us for recommendations on appropriate chassis and tire loads for such modifications to your truck. By selecting the appropriate tires for your bespoke work truck, you can ensure that the vehicle operates at full productivity.

Servicing bodies and other similar add-ons turn your newly bought car into a mobile workstation.

Check out our items at Reading Vehicle to learn more about service bodies and other ways to personalize your truck so that it performs optimally for what you do.

Keep Reading

I’m going to make the decision to get some new tires. However, I’m tossing up between a handful of other choices right now. The issue that I’m stuck on is the relationship between ride quality and load rating. LT tires are what I’m striving for, but I’ve got two different types: one that is Load Range C and the other that is Load Range D. These load ranges represent the number of plies in the tire, as well as the maximum load that can be carried at the maximum inflation pressures. My guess is that a load range D tire inflated to 65 pounds per square inch would ride like a rock.

Will this result in a ride that is more similar to my present ‘P’ rated tires when I use this inflation pressure?

When I have one of these load ranges, does this indicate that I have to inflate to a much greater pressure, or does it just mean that I have the choice of inflating to a higher pressure in order to manage heavier loads?

My regular ride is a Toyota 4Runner, and I’m beginning to soften as I grow older.

It appears like extra ply may be necessary even on city streets based on some of the potholes I’ve been dealing with. Is it possible that I’m making a mountain out of a molehill? Thank you very much. MadCityRich’02 4Runner Limited Edition MadCityRich’02 4Runner Limited Edition

Double Jeopardy: Right Size, Wrong Load Index Can Mean Liability Risk

Do you put the air pressure in a set of non-original equipment tires to the same level as you did in the original equipment tires when you sell them? More information is available by clicking here. Do your salespeople, managers, and technicians understand the significance of the load index in their jobs? Does the person know how to interpret a load and inflation table? Can they recall from memory the inflation rule, which states that the replacement tire’s load bearing capability must be equal to or greater than that of the original equipment tire?

  1. Not only must you teach your employees on these topics, but you must also document that training in order to be fully safeguarded against possible legal liabilities.
  2. You have every right to be.
  3. Here is an example of what might happen if you sell the correct tire size but the incorrect load index: More Complicated Than Ever BeforeThe world has evolved.
  4. Today is not one of those days.
  5. These days, you must examine each tire in detail, as well as its comprehensive size information, before making any fitting selections.
  6. In this case, the following information is provided: One A customer wants a pair of 20-inch tires for his 2003 Lexus LS430, which is currently equipped with 17-inch tires.
  7. The overall diameter (OD) is 26.8 millimeters (inches).

‘If the OD is accurate, then it must be the correct tire,’ you reason to yourself.

Check out that 20-inch tire’s load index to see how much weight it can handle.

The load index of the original equipment tire was 95.

‘How is this possible?’ you inquire.

The maximum load capacity of a standard load (SL) P-metric tire is reached at 35 psi, regardless of the maximum inflation pressure shown on the sidewall!

Per tire, the weight is merely 44 pounds.

This is what you should tell the judge when he reads a settlement against you for some crazy amount of money because ‘the new tire did not meet or surpass the load bearing capability of the original equipment tire.’ The proper tire for this plus-size application should be a 255/35R20 97H XL (extra load) tire with a load index of 97, which is a euro-metric (There is a difference!) tire with a load index of 97.

  • Suppose you installed this tire, which we now know is right, but you utilized the original equipment air pressure of 32 pounds per square inch (psi).
  • Using simple mathematics, you’ll discover the following: 1,477-1,290=187 pounds overloaded per tire, for a total of 748 pounds overloaded per tire.
  • Case Study Number Two One of our customers comes into the store and requests a pair of 20-inch tires for his 2004 Dodge Ram 1500 SLT Crew Cab RWD pickup truck.
  • You have a pair of take-offs from another Ram 1500 that have already been mounted with P275/55R20 111S tires installed on them.
  • Sure, they may ‘fit,’ but they will not be the proper tires for the vehicle.
  • Take a look at the load index of the 20-inch tire, which is 111 SL.
  • As a result, a lower load index will result in a reduction in maximum load capacity.

The right tire would be the optional tire that Dodge employs on its bigger trucks – the P275/60R20 114S – which is the exact size for this vehicle (SL).

You should, however, inflate the tire to 35 psi in this situation, which is higher than the minimum stated load capability of the tire.

Can you guess what the reason is?

A P-metric or euro-metric tire fitted on a light truck, according to the RMA, has a lower load capability than a standard tire.

P235/75R15 (SL) tires filled to 35 pounds per square inch would be an example of this.

Placing this identical tire on a light truck results in a load capacity of 1,844 (20281.1) pounds while the truck is driven.

When placing LT-metric or flotation tires on a light vehicle that already has OE P-metric or euro-metric tires, there are a number of other considerations to consider, so be certain that you have correct guidance before making these sorts of modifications.

The new rule, Federal Motor Vehicle Safety Standard110, which went into effect on September 1, 2005, states that if you ‘alter’ a new vehicle by installing different tires or wheels, you must place a new tire inflation and load capacity placard over the original placard to indicate to the buyer the new front/rear/spare air pressures and the new tire inflation and load capacity placard.

Placards can be ordered from a variety of label manufacturers.

Additionally, modifications in the vehicle’s maximum weight capacity are covered by this standard.

The National Highway Traffic Safety Administration (NHTSA) now allows for a 0.5 percent variation from the gross vehicle weight rating without updating the placard, but this may change in the coming months.

Tire pressure load rating – iRV2 Forums

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04-09-2021, 04:14 PM 1
MemberNewmar Owners ClubJoin Date: Sep 2017Location: Hattiesburg, MSPosts: 51 Tire pressure load rating


We took our 2015 Ventana 4037 to get her weighed today. I have attached a photo of the weigh ticket and the Continental tire load rating.From what I understand, it appears the front tires will need to be at 95psi. My question is how do I figure the drive axle weight between the duals and tag? I divided the steer axle weight by two. If I divide the drive axle by six I’m not even on the chart.Any guidance is appreciated.Click image for larger versionName: IMG_1334.jpg Views: 12 Size: 476.7 KB ID: 324435Click image for larger versionName: IMG_1335.jpg Views: 10 Size: 605.7 KB ID: 324436

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04-09-2021, 05:30 PM 2
Senior MemberJoin Date: Oct 2013Location: Westfield, IN, at the momentPosts: 263 Could you assume 2/3s of the total rear weight are being supported by the 4 tires on the drive axels 4 tires and the other 1/3 of total weight on the tag tires. But if/when you dump the air in the tag, you are bearing the rear weight on the 4 drive tires, so that should be your max weight per tire in the rear. Flame suit on-this is likely to be a lively discussion_Bob2015 Dutch Star 4369, Freightliner, 450 hp
04-09-2021, 05:36 PM 3
‘Formerly Diplomat Don’Newmar Owners ClubJoin Date: Apr 2005Location: Moorpark, Ca.Posts: 19,182 Your chart is blurry and hard to read, but when you figure out the pressure for the rears, you use the DUAL numbers, not the single. So you divide the front by two, which is 5900 pounds. Find the correct air pressure under SINGLE and round off to the next highest weight/number.On the rears, when divide by two, your weight is 11750 per side.find that weight under the DUAL column for your tire size, again, rounding up. Name:IMG_1334.jpg Views: 41 Size:40.9 KB  Name:IMG_1335.jpg Views: 45 Size:54.2 KB _DonMary2019 Newmar Dutch Star 4018 (Freightliner)2019 Ford Raptor
04-09-2021, 05:42 PM 4
Senior MemberMonaco Owners Club Solo Rvers Club Coastal CampersJoin Date: Mar 2020Posts: 728 Go back to the scales and get a weight for each axle. Depending on the air in the tags the weight might not be evenly spread across both axles. Make sure your fuel is topped off and the amount of water you plan to carry is in the tank._2009 Monaco Camelot 42PDQ2011 JK
04-09-2021, 06:13 PM 5
MemberNewmar Owners ClubJoin Date: Sep 2017Location: Hattiesburg, MSPosts: 51 Your chart is blurry and hard to read, but when you figure out the pressure for the rears, you use the DUAL numbers, not the single. So you divide the front by two, which is 5900 pounds. Find the correct air pressure under SINGLE and round off to the next highest weight/number.On the rears, when divide by two, your weight is 11750 per side.find that weight under the DUAL column for your tire size, again, rounding up.DS Don,I tried that but the dual chart shows a max load of 6940. How do I factor in the tag axle which is a single?
04-09-2021, 08:13 PM 6
Senior MemberNewmar Owners Club Winnebago Owners Club Spartan Chassis RV Trip WizardJoin Date: Mar 2006Location: Tyler, TexasPosts: 487 You’ll need to separate the axles on different areas of the scale to get a separate weight for each axle. Now that you have the steer axle, don’t worry about that and just have the drive and tag axles on separate pads._MillardSherry2019 Mountain Aire 4018Toad 2014 Honda CRV or 2019 GMC CanyonM G Braking-Roadmaster Towbar
04-09-2021, 08:29 PM 7
Senior MemberNewmar Owners Club Freightliner Owners ClubJoin Date: Feb 2016Location: MississippiPosts: 576 This may not help you. Based on my weights per axle/tire position the tag tires carries about 1/2 the weight of the duals. I have two separate CAT scale weights checks which are combined duals and tag. Both are within 1K of each other. I also have two individual tire weights checks which are within 1K of each other. The CAT and individual weights checks for the dual/tag tire weights are within 1800across the 4 weight checks. Based on these my tag tires runs about 1/2 of what the dual tires carry._2016 Newmar Ventana 40022020 Jeep Gladiator
04-09-2021, 08:46 PM 8
MemberNewmar Owners ClubJoin Date: Sep 2017Location: Hattiesburg, MSPosts: 51 I’ve been researching previous posts regarding the Continental load/pressure table. I see other people have the same problem with the ‘dual’ portion of the chart. No matter how I try and break down the weight numbers for the drive axle I can’t find it on Continental’s table.Stang37,Out of curiosity, what pressure do you run in your duals and tag? The previous owner of my coach said he ran 95psi in the steer axle and 90 in the duals and tag. 90psi just seemed a bit low to me.I might try and contact Continental soon. I just need something reasonable until i can get the manufacturers recommendation.
04-09-2021, 09:22 PM 9
Senior MemberNewmar Owners Club Spartan ChassisJoin Date: Aug 2015Location: Northwest Washington State or Western Montana, depending on the season.Posts: 3,473 Quote:Originally Posted byChief DeputyOut of curiosity, what pressure do you run in your duals and tag? The previous owner of my coach said he ran 95psi in the steer axle and 90 in the duals and tag. 90psi just seemed a bit low to me.Our 2018 Mountain Aire is significantly heavier than the Ventana listed in your profile and we run 90 PSI in the drive and tag tires, even though Newmar said we could run 85 after they weighed the coach during our last visit to Nappanee. If the tire manufacturer’s pressure chart for the scale weights (and, you should have individual weights done for the steer, drive and tag axles) indicate 85 psi is safe, it is.I like DS Don’s rounding up idea (which is what we did when Newmar recommended 85 psi); it gives you an additional safety cushion. So, if you feel 85 psi is too low, move up to 90 psi and be confident that you are safe. I’m guessing that when you get individual axle weights on your coach, it may well be that 80 psi is acceptable; 85 psi would give you just a bit more of a safety factor.Above all, don’t guess at axle weights and tire psi; get the individual axle weights of your travel-ready coach and use the charts.TJ_Jim (W7DHC), DianeMini Schnauzers, LizzyEllie2018 Mountain Aire 40472014 Honda CR-V2020 Lincoln Nautilus ‘toad’ w/AF1
04-09-2021, 09:50 PM 10
‘Formerly Diplomat Don’Newmar Owners ClubJoin Date: Apr 2005Location: Moorpark, Ca.Posts: 19,182 Quote:Originally Posted byChief DeputyYour chart is blurry and hard to read, but when you figure out the pressure for the rears, you use the DUAL numbers, not the single. So you divide the front by two, which is 5900 pounds. Find the correct air pressure under SINGLE and round off to the next highest weight/number.On the rears, when divide by two, your weight is 11750 per side.find that weight under the DUAL column for your tire size, again, rounding up.DS Don,I tried that but the dual chart shows a max load of 6940. How do I factor in the tag axle which is a single?Sorry.I didn’t see that you had a tag. You need the tag weight, figure as a single and then do the new dual numbers, under the DUAL chart.You can email Newmar and get your weight as the coach came off the assembly line. They’ll give the numbers for all three axles. They’ll be pretty close on the weight of your tag._DonMary2019 Newmar Dutch Star 4018 (Freightliner)2019 Ford Raptor
04-10-2021, 08:42 AM 11
Senior MemberJoin Date: Nov 2007Location: Charleston, WVPosts: 3,360 I had all my corners weighed individually and verified that the tag is set to 50% of the dual drive wheels. In that case all six tires at the rear carry the same load. When I checked the Michelin pressure charts I could safely inflate my tires to 80 psi, which is the minimum pressure the XRV tires should be inflated to. From the initial post it appears the coach has Continental tires, which must be Urban HA3, and these may have a different pressure range. I would be interested to hear how these tires are working as they are on my short list for replacements._John and Mary Knight2015 Newmar Ventana 4311 – wheelchair accessible2015 Cadillac SRX Luxury AWD
04-10-2021, 11:46 AM 12
‘Formerly Diplomat Don’Newmar Owners ClubJoin Date: Apr 2005Location: Moorpark, Ca.Posts: 19,182 Chief Deputy.Since Newmar is one of the only companies that produces a 40′ coach with a tag axle, the rear duals and tag don’t individually carry a lot of weight. Consequently, you may find that your weights are at the low end of the tire chart and sometimes below their lowest setting. So there is a minimum that you need to use, often around 80 – 85 psi._DonMary2019 Newmar Dutch Star 4018 (Freightliner)2019 Ford Raptor
04-10-2021, 02:09 PM 13
Senior MemberJoin Date: Oct 2009Posts: 768 Click image for larger versionName: IMG_4853.jpg Views: 22 Size: 334.3 KB ID: 324518I did a four corner weight yesterday and wanted to share the results. I hadn�t done it for a long time but with 8 new Michelin X Line Energy 315/80 R22.5 all the way around, I wanted to be sure I had the right psi and weight on each axle. Here�s the information:2010 Dutch Aire 43� with tag axleFront axle rating: 16,000 lbsFront right wheel: 7,300 lbsFront left wheel: 7,600 lbsCombined front axle: 14,900 lbs* need to add 200 lbs driver and 150 lbs for passenger Tire pressure set at: 115 psiDrive axle rating: 20,000 lbsDrive axle right: 7,450 lbsDrive axle left: 6,950 lbsCombined drive axle: 14,400 lbsTire pressure set at: 90 psi* minimum is 85 but I didn�t want to drop below that number ever. We will be adding weight to rear closet.Tag axle rating: 10,000 lbsTag axle right: 3950 lbsTag axle left: 3,950 lbsCombined tag axle: 7,900 lbsTire pressure set at: 90 psiRight side combined weight: 18,700 lbsLeft side combined weight: 18,500 lbsTotal weight of RV: 37,200 lbs. GVWR: 46,000 lbsComments welcome._Rich NKK192662010 Dutch Aire 43172014 Grand Cherokee Summit Ecodiesel
04-10-2021, 02:53 PM 14
Senior MemberNewmar Owners Club Spartan ChassisJoin Date: Aug 2015Location: Northwest Washington State or Western Montana, depending on the season.Posts: 3,473 Quote:Originally Posted byenjoyrvAttachment 324518I did a four corner weight yesterday and wanted to share the results. I hadn�t done it for a long time but with 8 new Michelin X Line Energy 315/80 R22.5 all the way around, I wanted to be sure I had the right psi and weight on each axle. Here�s the information:2010 Dutch Aire 43� with tag axleFront axle rating: 16,000 lbsFront right wheel: 7,300 lbsFront left wheel: 7,600 lbsCombined front axle: 14,900 lbs* need to add 200 lbs driver and 150 lbs for passenger Tire pressure set at: 115 psiDrive axle rating: 20,000 lbsDrive axle right: 7,450 lbsDrive axle left: 6,950 lbsCombined drive axle: 14,400 lbsTire pressure set at: 90 psi* minimum is 85 but I didn�t want to drop below that number ever. We will be adding weight to rear closet.Tag axle rating: 10,000 lbsTag axle right: 3950 lbsTag axle left: 3,950 lbsCombined tag axle: 7,900 lbsTire pressure set at: 90 psiRight side combined weight: 18,700 lbsLeft side combined weight: 18,500 lbsTotal weight of RV: 37,200 lbs. GVWR: 46,000 lbsComments welcome.Good data and congrats on a well-balanced coach! That�s how it should be done.TJ_Jim (W7DHC), DianeMini Schnauzers, LizzyEllie2018 Mountain Aire 40472014 Honda CR-V2020 Lincoln Nautilus ‘toad’ w/AF1
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