One year ago, NATM announced the launch of its Dealer Affiliate Program. The Association has been committed to the light- and medium-duty trailer industry for more than 30 years, with its focus on the manufacturing of compliant trailers. The extension to include trailer dealers as affiliates was a natural next step in the evolution of NATM’s expanding trailer safety efforts.
NATM Dealer Affiliate Program
Trailer dealers serve as the main point of contact during the sales process of many NATM compliant trailers. This group is also a key stakeholder in the fight to improve trailer safety as it is in their best interest that their customers are safe and happy with their purchase. As a result, NATM created the NATM Dealer Affiliate Program.
Increasing end-user awareness of the importance of the NATM Compliance Verification Program has consistently ranked as a top priority for trailer manufacturing members. By bringing trailer dealers in as affiliates, NATM is better able to serve its membership by directly communicating about the importance of purchasing NATM compliant trailers.
The NATM Dealer Affiliation is $150 and affiliates experience a host of benefits, with an emphasis on education and resource access. The following list includes current Dealer Affiliate benefits:
Samples of NATM publications:
More details about the program can be found at www.natm.com/dealers.html. Have ideas for additional benefits? Contact NATM Membership & Events Director Kelli Maydew at Kelli.Maydew@natm.com or call (785) 272-4433.
Dealers Invited to NATM Convention!
For the first time in NATM history, the Association is excited to invite trailer dealers to the 33rd Annual NATM Convention & Trade Show in Nashville, Tenn. Feb. 23-25, 2021! Dealer attendees will have the opportunity to participate in all workshops and technical forums, along with dealer-centered educational sessions. Plan to attend the trade show, which will house 298 booths! Special networking events will provide the opportunity to mingle with fellow industry peers, NATM Board Members and staff, and trailer manufacturers while in Music City.
NATM will be offering a “New Dealer Promotion!” Companies can sign up for NATM’s Dealer Affiliate Program for just $150 and are then eligible for two complimentary registrations and two free hotel room nights while available! Non-affiliate dealers can register to attend for $300.
For the first time in NATM history, the Association is excited to invite trailer dealers to the 33rd Annual NATM Convention & Trade Show in Nashville, Tenn. Feb. 23-25, 2021!
NATM has been committed to trailer safety for more than 30 years. While NATM has long worked with trailer manufacturers, industry suppliers, and service providers, trailer safety can only be improved through dealer interaction and consumer education. Expanding the Association’s base to include dealer affiliates and now allowing dealers to attend the Annual Convention & Trade Show is the logical next step to advancing the mission of NATM.
The NATM Convention & Trade Show is the annual trade show for the light- and medium-duty trailer industry. With more than 1,000 trailer manufacturer and supplier attendees per year and growing, this "must attend" event provides education, networking and communication for those in the industry. The 2020 soldout trade show boasted over 200 exhibiting companies, with 37 new exhibitors, which gave attendees a variety of products and services to view. The show also included attendees from over 100 trailer manufacturers companies from across North America.
Dealer attendees will have the opportunity to participate in all workshops and technical forums, along with dealer-centered educational sessions. Plan to attend the trade show, which will house 298 booths and an opportunity to network with manufacturers and distributors! Of course, don’t forget the awards luncheon – join your industry peers for a plated lunch and perhaps be the first ever dealer to win an award from NATM. Special networking events will provide the opportunity to mingle with fellow industry peers, trailer manufacturers, and NATM Board Members and staff while in Music City.
NATM is thrilled to involve dealers at the annual show! The Association’s purpose is to open up lines of communication, increase trailer safety awareness, and provide dealers with the education and information they have long requested from NATM. NATM has worked diligently with committees, trailer manufacturers, industry suppliers, and dealers to create a path of inclusion for dealers. NATM can’t wait for you to see what they have planned!
NATM will be offering a “New Dealer Promotion” to help offset costs for dealers attending the show. Companies can sign up for NATM’s Dealer Affiliate Program for just $150 and are then eligible for two complimentary registrations and two free hotel room nights while available! The NATM Dealer Affiliate program is an opportunity to unify the trailer industry in an effort to improve trailer safety and gain access to resources and information previously only available to trailer manufacturers and industry suppliers. To read more about the Dealer Affiliate Program, visit NATM.com/dealers. Non-affiliate dealers can register to attend for $300.
Contact NATM Membership & Events Director Kelli Maydew at Kelli.Maydew@natm.com or
(785) 272-4433. Online registration will open this Fall. NATM looks forward to seeing you in Nashville!
It’s time to get your trailer ready for warmer weather! After a long winter sitting unused, make sure your trailer is safe before you hit the road. Below are recommendations for readying your trailer for use. For more information about safe trailering and proper maintenance, visit www.TrailerSafetyWeek.com.
Check the tires on both the trailer and tow vehicle, looking for damage after long winter months. Make sure you inspect the tread for uneven wear. Verify that tire pressure is correct, and don’t forget the spare tire. Proper tire pressure affects vehicle handling and safety. You can find the correct tire pressure for your tow vehicle in the owner’s manual or on the tire information placard. Under-inflation reduces the load-carrying capacity of your tow vehicle or trailer, may cause sway and control problems, and may result in overheating, causing blowouts or other tire failures. Over-inflation causes premature tire wear and affects the handling characteristics of the tow vehicle or trailer.
Inspect all wheel lug nuts and make sure they are tightened to specifications.
Inspect the springs, spring bushings, and hangers for wear and cracks. This kind of preventative maintenance can save your trailer from a dangerous and expensive breakdown on the road.
Wiring and Lights:
Make sure connector-plug prongs and receptacles, light bulb sockets, wire splices, and ground connections are clean and shielded from moisture. Lightly coat all electrical terminal connections with nonconducting (dielectric), light, waterproof grease. Make sure all running lights, brake lights, turn signals, and hazard lights are working. Verify the wiring is connected correctly, not dragging on the road but loose enough to make turns without disconnecting or damaging the wires.
Verify that you have two safety chains and inspect for wear or damage. When you hook to the towing vehicle, cross the chains, so if the hitch comes loose, the crossed chains will catch the hitch.
Check your wheel bearings before returning your trailer to regular use and be sure to replace according to the trailer manufacturer’s recommendations. Have the bearings serviced, which requires a repack, new grease, a new bearing, and a new bearing race. Refer to your owner’s manual for maintenance information.
Make sure dust caps are still in place and have not cracked or otherwise been destroyed. Replace if necessary.
Verify the brakes on the tow vehicle and trailer are operating correctly. Regularly have the brakes on both the trailer and tow vehicle inspected. Be sure the necessary adjustments are made, and any damaged or worn parts are replaced. Check to see how much brake pad material remains. The start of the warmer months is a good time to replace them if they are getting close to the end of their life expectancy.
Ensure the breakaway system lanyard is connected to the tow vehicle but not to the safety chains or ball mount.
Hitch, Coupler, Draw Bar:
Make sure the hitch, coupler, draw bar, and other equipment that connect the trailer and the tow vehicle are properly secured and adjusted. Check the nuts, bolts, and other fasteners to ensure the hitch remains secured to the tow vehicle, and the coupler remains secured to the trailer. Lubricate the connection point if necessary, to permit free movement of the coupler to the hitch ball. Inspect the coupler ball socket to ensure it is not bent or dented. Any indentions could cause the ball not to seat properly, which can lead to detaching from the trailer.
If the trailer is loaded, check that all items are securely fastened on and in the trailer. Check load distribution to make sure the tow vehicle and trailer are properly balanced front to back and side to side in accordance with the owner's manual specifications.
Jacks and Accessories:
Be sure the trailer jack, tongue support, and any attached stabilizers are raised and locked in place. Put all jack stands up, and do not forget to bring the wheel chocks.
Tow Vehicle Maintenance:
Tow vehicles have frequent maintenance requirements. Spring is a good time to change the oil in the engine and transmission, lubricate components, inspect brakes, inspect belts and hoses, top off fluids to their recommended levels, check the radiator and cooling system, inspect the battery, and check the air conditioning system.
Tow Vehicle Mirrors:
Inspect tow vehicle mirrors for damage and cleanliness to make sure you have good visibility.
Tow Vehicle Tools, PPE, and Accessories:
Make sure you have a jack and lug wrench secured in the tow vehicle that is the appropriate size for the tow vehicle and trailer lug nuts. Verify the jack you packed up is suitable for both the vehicle and trailer capacities. Pack work gloves, safety glasses, and a mat or blanket in case you need to complete maintenance procedures or change a tire. Make sure all the tools are functioning correctly before packing.
Flooring, Body, Fenders, Cargo Securement Attachments, and General Trailer Structure:
Inspect trailer flooring for chips, cracks, and excessive wear. Make sure body panels and fenders are secure and in normal functioning order. Visually inspect the trailer structure to make sure nothing has rusted out or worn out during the harsh winter months. Replace or secure parts if necessary.
Give the trailer a once over visual inspection for cracked welds. Welds often break, especially when trailers are regularly subjected to heavy loads. Inspect carefully, as even hairline cracks can escalate quickly to much larger problems. Pay special attention to the stress points of the trailer when inspecting. In particular, check where the tongue attaches to the trailer and the points where the spring hangers are welded to the trailer frame.
Ramps and Tailgate:
Make sure the ramps are secured to the trailer and whatever pin or locking device that holds the ramps in place is still in its proper location and functioning. Verify the tailgate is secure but still allows for free movement. Lubricate hinges and other components if necessary.
Trailers with Dump Bodies and Hoists:
Check all fluid levels, hydraulic hoses, and the hoist unit. Clean and inspect the power unit for the hoist. Check electrical wires and battery corrosion for wear. Apply grease to hoist grease fittings, or zerks, as needed. Replace parts if necessary.
Plan ahead and determine your route by checking for restrictions, bridges, tunnels, and avoidable construction zones.
For more information about proper trailer maintenance, refer to your trailer’s owner’s manual. Trailer safety resources are also readily available and free to use at www.TrailerSafetyWeek.com.
Dealers should educate their customers on the importance of understanding a trailer’s gross vehicle weight rating (GVWR) and tow vehicle towing capacity. All too often, customers are not familiar with what trailer GVWR or cargo capacity means. Nor are they familiar with what this will require from their tow vehicle in terms of its towing capacity. This lack of information can lead to dissatisfaction if customers fail to complete necessary research before the purchase of the trailer, or if the trailer dealer personnel fails to ask the correct questions to ensure their customer is selecting a trailer that meets their needs and legal requirements.
First, the tow vehicle must be analyzed. What is the model of the customer’s pickup truck, SUV, minivan, or car? All vehicles capable of towing have owner’s manuals with maximum rated towing capacities. What often gets overlooked is maximum in this context, which truly means maximum. For example, if a customer has a tow vehicle with a towing maximum capacity of 7,000 lbs., they may not want a 7,000 lbs. GVWR trailer. The customer needs to take into serious consideration the fact that they will be at maximum capacity. Even without accidentally overloading the trailer, the tow vehicle will be working at its maximum capacity and not handle as well. As a result, they could find that their tow vehicle does not have enough power to merge with traffic on interstate on-ramps, to pass other vehicles, or to climb long hills and mountains. Trailer customers end up dissatisfied if they have purchased too much trailer for their tow vehicle. Unfortunately, simply purchasing a larger tow vehicle with a larger towing capacity is not an affordable solution to this problem and preventative measures by the dealer are the best route to customer satisfaction.
Dealers should ask the customer what their intended tow vehicle will be and if they are committed to that tow vehicle for the next few months, the next few years, or just the next few minutes. The customer could be vehicle shopping at the same time they are trailer shopping or may be willing to upgrade in the near future. From there, the trailer dealer can assist the customer in choosing a trailer that their current tow vehicle can handle. Or, in the event that the customer is in the market for a new tow vehicle, dealers can advise customers to purchase a certain category of tow vehicle that meets or exceeds a certain towing capacity threshold. It is a crucial conversation to have at the point of sale as many customers think their tow vehicle will perform adequately towing a certain model of trailer, only to find out too late that they should have either purchased a smaller trailer or upgraded their tow vehicle to handle the larger trailer model.
After the tow vehicle conversation, the topic can turn more specifically to the trailer. Dealers should make sure customers understand that the combination of the shipping weight of the trailer plus the trailer's cargo capacity should never exceed the trailer’s GVWR listed on its VIN. The shipping weight information can be found on the manufacturer’s certificate of origin (MCO), while the cargo capacity is often listed on the trailer’s tire placard.
For example, if a trailer’s GVWR is 7,000 lbs., the customer's tow vehicle should have a towing capacity that is 7,000 lbs. or preferably more. It is also crucial that the customer not overload the trailer. If the trailer itself weighs 2,700 lbs., the customer should never put more than 4,300 lbs. of cargo in it, because 2,700 lbs. plus 4,300 lbs. equals 7,000 lbs. GVWR, which the trailer should never exceed.
Another critical dealer/customer conversation is what cargo the customer intends to tow. If the customer plans to haul a rock crawler SUV and camping gear that adds up to 5,500 lbs. in the example above, they cannot safely do that with the same trailer. The calculation for this example is the combination of the trailer weight of 2,700 lbs. plus the cargo of 5,500 lbs., which equals 8,200 lbs. This means the trailers’ GVWR would need to be 8,200. But, because the GVWR of this trailer is 7,000 lbs., this customer has overloaded their trailer by 1,200 lbs.
If the customer tells the dealer in this example that they intend to haul an estimated 5,500 lbs. of cargo, the dealer needs to explain to the customer that they should purchase a larger trailer with a higher cargo capacity. If the customer says their tow vehicle cannot haul a larger trailer, then the trailer dealer needs to explain to the customer they need both a larger tow vehicle with a higher towing capacity and a larger trailer with a higher cargo capacity. If this is not possible, the customer needs to find a way to haul significantly less cargo. The customer might be disappointed upon learning this, but later they will be appreciative of the dealer’s honesty, which leads to long term customer loyalty. The NATM Guidelines contain a section on trailer GVWRs. For more information, contact NATM’s Technical Director Colin Holthaus at Colin.Holthaus@natm.com or (785) 272-4433.
Causes of Corrosion
For decades, sodium chloride (rock salt), calcium chloride, and magnesium chloride have been used for de-icing roadways. The presence of salt dramatically enhances the rusting of metals. Road debris, sand, gravel, and other deicing materials can damage trailers as well. These substances leave chips in the trailer’s coating and expose the underlying substrate to the corrosive environment.
Many trailer components are also vulnerable to galvanic corrosion caused by dissimilar metals making contact. A simple maintenance repair that pairs the wrong nut, bolt, or washer can create a corrosive response. Problems can also occur as a result of tightened fasteners, which can dislodge surface coatings, exposing reactive metals to one another and the elements. Areas on a trailer with high exposure to road-born moisture, such as around tires, are areas where corrosion is most likely to occur. Other important areas to inspect for corrosion on trailers include rear frames, gussets, rear underride guards, threshold plates, front aprons, upper couplers, landing gear brackets and braces, cross members, end clips, front under-structure, suspension, and axle assembly components, and any ledges underneath a trailer that allow debris to enter.
Roadway pretreating products such as calcium chloride and magnesium chloride are very corrosive and react even to low humidity. Because of this, these substances should be washed off a trailer as soon as possible after coming in contact with them. For example, if a trailer traveled over a road treated with these chemicals in Oklahoma, and concluded the trip in warm weather in Texas. Throughout the eight to ten-hour journey, these corrosive chemicals will continue to react even in low humidity until the trailer is thoroughly washed. To combat this, some of the nation’s largest fleets have implemented daily underbody wash procedures during winter months to prevent corrosive damage caused by the reaction of these two chemicals.
Preventing & Treating Corrosion
Today, trailer manufacturers can use a range of approaches to prevent corrosion when they build trailers. There are also various options on the market available for corrosion prevention on in-service trailers. Trailer manufacturers can fight corrosion on a trailer’s structural cross members with paint applications, two-step zinc and paint combinations, epoxy coatings, and construction methods using galvanized, stainless steel, or aluminum components.
For trailers already in-service, trailer technicians address corrosion issues by taking into consideration what type of corrosion-fighting method was initially used on a vehicle when making repairs. Some coatings and materials are more expensive, and some are more difficult to work with than others. In some instances, a touch-up job may be all that is necessary to slow down or stop the corrosion process.
In addition to several paint applications, galvanized aluminum and stainless steel are very effective in the fight against corrosion. This process applies a protective zinc coating to protect metals from rusting. The zinc prevents corrosive substances from reaching the underlying metal and, when scratched, serves as an anode for the exposed metal surface. Other kinds of protective coatings can also offer a feasible and long-term solution for corrosion control, without the issues inherent in soft film barriers and galvanizing methods. Polyureas and polyurethanes provide exceptional durability and chemical resistance, even in extreme weather. They are flexible and impact resistant and will not cut, peel, crack, or chip. These coatings are similar to spray-on truck bed liner material but have unique properties.
Once the end-user has purchased the trailer, they can take a few proactive steps to address corrosion. First, they should develop a habit of taking the extra time to wash, clean, and detail their trailer before storing it in a clean, dry, and protected environment. This will not only help keep the trailer looking good; it will prevent corrosion and increase the useful life of the trailer. As part of the cleaning process, trailers should be thoroughly cleaned before storing them, including under the floor mats in livestock trailers. Trailers with certain coatings can even be waxed once or twice per year with several automotive detailing products, subject to the trailer manufacturer's recommendations. Owners should conduct maintenance inspections regularly and have any corroded areas immediately addressed by professionals before the corrosion continues to spread. Just like in the used automobile market, taking care of trailers and preventing corrosion pays off when it comes to preserving the resale value of the trailer.
The NATM Safely Towing a Trailer brochure has been updated to feature a new section on corrosion prevention. Published in 2019, the brochure has expanded its maintenance section to educate end-users about their role in preventing rust. To order NATM products, visit www.natm.com/products.
For a list of NATM Associate Members that supply paints and other protective coatings, visit the NATM Online Buyer’s Guide at www.NATM.com. For more information regarding the manufacture of trailers, contact NATM Technical Director Colin Holthaus at Colin.Holthaus@natm.com or (785) 272-4433.
This pre-departure checklist is a great tool for your customers. Before towing a trailer, make sure the tow vehicle and trailer maintenance is current. This is very important because towing puts additional stress on the tow vehicle.
Is it necessary to balance trailer tires? Is it an unnecessary expense? Like many complicated issues, the answer is that it all depends. Since the primary duty of a trailer tire is supporting a vertical load, rather than gripping an automobile through turns, trailer tires do not have to be dynamically balanced like passenger car tires do. Steering and cornering are less of a concern on a trailer tire than they are on an automotive tire. Balanced passenger car tires prevent the passengers inside a vehicle from feeling the bumps and irregularities of the road at higher speeds. Although some trailer cargo requires the smoothest of rides, trailers transport cargo and equipment, rather than passengers, so the standard for ride quality is usually less of a concern.
The Challenges Associated with Balancing Trailer Tires
Trailer owners may struggle over the long haul to keep trailer tires balanced because their wheels tend to "throw weights." In other words, the tire balancing weights end up coming off of the trailer wheels during normal trailer usage, which can happen for a number of reasons. It is not uncommon for the weights to be thrown off when towing an unladen trailer because the trailer may bounce excessively without a load, especially through potholes and over rough terrain. Tandem or triple-axle trailers tend to throw weights when making tight turns as well.
Another aspect that makes balancing trailer tires challenging is that most automotive service centers are not equipped with the proper wheel balancing machine to correctly balance most trailer tires. Most trailer wheels are a lug centric design which means the wheels are centered on the hub by the torque of the lug nuts. On the other hand, many automotive wheels are a hub centric design. Most automotive service centers use a computerized "cone" balancer which works great on automotive hub centric wheels, but does not work very well on lug centric trailer wheels. In order to correctly balance trailer wheels, an adapter must be used on the cone balancer. To save time and avoid a wasted trip, customers should check with their automotive service center beforehand to make sure the company has the adapter to properly balance trailer tires.
Further complicating the issue is the fact that many trailer wheels are galvanized, and galvanized trailer wheels are usually not designed to be balanced. When the steel wheel is hot dipped galvanized, some of the liquid zinc often accumulates on one end. This can make galvanized wheels difficult to balance. However, the upside of galvanizing is the galvanized coating provides corrosion resistance to harsh environments such as salt water. If end-users are not sure whether or not their trailer wheels are galvanized, they should ask their trailer manufacturer or wheel manufacturer, and follow the wheel manufacturer’s specific instructions on whether or not they should balance their tires and if so, how best to do so.
How does the Trailering Application Factor In?
Customers purchase trailers for a wide variety of reasons, and the intended use of the trailer is a significant factor when deciding whether to balance the trailer tires. For example, recreational vehicle trailers and boat trailers are often stored outside in harsh environments. These trailers are typically only pulled on a handful of trips each year. Some customers will not balance tires on these trailer models because they feel the tire will wear out from dry rot long before the tire tread is actually worn or any substantial benefit would be derived from having the tires balanced.
In addition, the size of the trailer and the type of cargo transported are other useful factors for determining if tire balancing is necessary for a specific trailer. Valuable, fragile cargo may be more protected and have a smoother ride with balanced tires. In addition, trailer cargo can have a rough ride if vibration and suspension components lend themselves to instability when the trailer is on rougher roads, or the trailer is improperly loaded.
Another trend in recent years is installing custom wheels on trailers, including chrome and aluminum. These wheels have an attractive look and are typically acceptable for each trailer as long as the trailer manufacturer or end-user makes sure the wheels have the correct weight capacity for their trailer, as well as the correct wheel offset, which will assist in making sure the load is over the hub bearings.
How do Wheels Factor In?
Customers can have their trailer tires balanced if they wish, but it is not essential to the proper operation of most trailers. As was previously mentioned, there are two distinct types of wheels found on today’s cars and light trucks. Hub centric wheels are centered by the center bore of the wheel and hub flange. Most trailer wheels are lug centric and are centered by the torque of the lug bolts, rather than the center bore of the wheel and hub flange. The most common automotive wheels are hub centric in design. The center hole of these wheels are the actual center bore of the wheel. If new tires are purchased for a set of stock wheels, the customer can have them balanced if they choose. If the customer balances the tires, they must take into account that many trailer wheels are lug centric. To get the best tire balance for lug-centric wheels, the tires should be balanced by a shop that uses a pin plate adapter. This mimics the way a lug-centric wheel is mounted to a hub and will result in the best overall outcome.
Many tire and wheel manufacturers balance tires by mounting their tire and wheel assemblies so the high, heavy spot on the tire is aligned with the low, light spot on the wheel. This provides adequate balancing for many trailer tires. Many trailer manufacturers purchase their tire and wheel assemblies mounted and inflated to PSI specifications from the factory. However, some do not, and it depends on the terms of the trailer manufacturer’s agreement with their tire and wheel supplier. Some end-users insist their trailer tires be balanced, but the majority of trailer customers are probably not concerned with whether or not the tires are balanced. Most end-users simply want their trailer to adequately perform its function. However, in some applications the end-user may not be aware that adequate performance for their particular trailer requires that the trailer tires be balanced or balancing the tires would greatly improve the ride quality of the trailer.
In the trailer manufacturing industry, a successful business is dependent upon an educated, highly skilled workforce. Does your company have the necessary tools to keep up with the demanding job market? The answer lies in workforce development – a necessity for both employees and businesses to remain competitive, particularly in today’s economy.
Questions? Contact Membership & Events Director Kelli Maydew.
NEW: Referral Program
The National Association of Trailer Manufacturers (NATM) has been committed to trailer safety for more than 30 years. While NATM has long
worked with trailer manufacturers, industry suppliers and service providers, trailer safety can only be improved through dealer interaction and consumer education. The launch of the NATM Dealer Affiliation is an opportunity to unify the trailer industry in an effort to improve trailer safety.
NATM Dealer Affiliates will experience a host of benefits, with an emphasis on education and resource access.
NATM is collecting the contact information for trailer dealers across the country in order to distribute safe trailering resources. For every 50 dealer contacts that your company sends to NATM, you can receive a $100 discount on advertising with NATM!
To learn more, please visit our Dealer Affiliate page.
Tier 1: 1- 4 Companies Referred
Tier 2: 5-9 Companies Referred
Tier 3: 10+ Companies Referred
Companies must inform NATM of their referral on the Dealer Affiliate Application in the space provided on the form for a referral to be counted. For more information, contact NATM Membership & Events Director Kelli Maydew at Kelli.Maydew@natm.com.
*Please note, all incentives are available for 12 months following the convention or the following year’s convention. Any incentives not used will expire.
Understanding all the writing on the sidewall of a tire can be overwhelming. It helps to know what characters you are searching for in order to obtain the tire information you desire. For example, if the tire code was 225/45R17 75L, then 75 would signify the load index and L would signify the speed rating of the tire.
The load index tells you how many pounds a tire can safely carry. As you can see on the load index chart below, the 75 in the example above has been assigned a load carrying capacity of 853 lbs per tire. Multiply the load carrying capacity by the number of the tires on the trailer. As long as that sum is greater than or equal to the assigned GVWR of the trailer, then the tire’s load index is sufficient for its application.
Speed ratings are based on laboratory tests and were established to match the speed capability of tires. In the same tire code example stated previously, L would signify the tire speed rating. According to the attached chart, the speed rating
for L is up to 75 mph. It has been proven under testing conditions, that tire can operate for a certain period of time up
to 75 mph.
Motor vehicles should always be operated according to the speed limit of the roads they travel on. Never exceed the speed rating of the tow vehicle tires or the trailer tires; drive according to whichever rating is lower. Trailer tires commonly have tire speed ratings in the 65 – 75 mph range. Unless otherwise noted, the speed rating for trailer tires is 65 mph.