For Want of a Tire: Analysis of Fuel Efficient Truck Tires and Manufacturers (from EPA Smartway Verified list as of December 2015) – Version 0.9
As the famous proverb teaches1, overlooking something as small as a nail, or a tire, can result in unintended and even devastating consequences. As I published my study of aerodynamic truck modifications, it had also become clear that tires had a significant role to play in the efficiency of a truck, its greenhouse gas emissions and its cost to fleets and deserved attention.
The importance of tires grew in my mind once I began to recognize that many trucks were running not just two tires on each side of an axle (commonly known as duals, similar to dualies / dually / duallys on pickups), but a single large tire on each side of an axle (known as super singles or wide base singles – WBS). I knew I needed to know more.
While the efficiency difference the least and most fuel efficient tires of a few percent in miles per gallon is typical, differences between the worst non-fuel efficient tires and best fuel-efficient tires can easily get into the the double digits, making the conversion to fuel efficient truck tires a winning argument on the money side of the equation, all else being equal. But not all is equal, from the cost of the tire to how many miles those tires get to their safety on the road. These and other considerations need to be weighed when choosing a fuel efficient tire.
Fuel Efficient Tire Analysis Setup
Tires are seemingly simple; they are the round rubber rings on which the smallest to largest vehicles run on top off; everyone knows that. What I eventually found out is that far more than for consumer tires, choosing a commercial tire involves many, many factors. But to start, what makes a tire fuel efficient?
Tires are the final part in the path of parts by which energy created by an engine is transferred to the movement of the vehicle. At each step in that pathway, energy is consumed by by the need to start and keep the vehicle moving and inefficiencies (friction, thermal loss, resistance). “Rolling resistance” is the force required to keep a tire rolling at constant speed on a level surface, a force that increases as the weight increases.2
Rolling resistance in truck and other rubber vehicular tires is primarily energy loss due to internal flexing, compression and and stretching of the tires although a little bit is from aerodynamic drag on the tires and road friction. Thus a low rolling resistance (LRR) tire is one that has a lower rolling resistance versus some standard reference tire.
I needed a starting point and in answer to the question, “Is there a list of fuel efficient truck tires that already exists?”, it was “Yes!”. The United States Environmental Protection Agency (US EPA) has created a list of Smartway Verified Low Rolling Resistance Tires which can be found on the second tab of this page3.
The US EPA Smartway program, founded in 2004, is a “collaboration between freight shippers, carriers, logistics companies and other stakeholders, to voluntarily achieve improved fuel efficiency and reduce environmental impacts from freight transport.” 4
How Does a Tire Become a Smartway Verified Tire?
Two answers to how a tire becomes Smartway Verified arise from my research.
The first comes from this official document titled “SmartWay Verified Low Rolling Resistance Tires Performance Requirements”.
That document specifies that the tires need to have a maximum measure of tire rolling resistance, or more precisely Rolling Resistance Coefficient in kg force/metric ton, depending on which standardized rolling resistance test is being run: between 6.5 and 6.9 for a steer tire, 6.6 and 7.0 for a drive tire and between 5.1 and 5.5 for a trailer tire.
Put another way, a tire is mounted on a spinning contraption and spun against a spinning “drum” during which weight is precisely applied and measured simulating driving. Those tires that demonstrate resistance at or below the above ranges are labeled Smartway Verified tires and put onto EPA’s tire list.
Two laboratories performing these analyses are Smithers Rapra and Standards Testing Labs; it isn’t clear how many other laboratories and test facilities run these tests, if EPA accepts those tests, whether any of these laboratories exist in other countries, or if the EPA pre-certifies the laboratories in any way.
The other potential answer comes from EPA’s Smartway home page which says:
“EPA demonstrated that certain low rolling resistance tires can reduce NOx emissions and fuel use of long haul class 8 tractor-trailers by 3 percent or more, relative to the other popular high rolling resistance tires.”
Versions of this statement are used across the Internet, including the authoritative North American Council for Freight Efficiency (NACFE) and its “Trucking Efficiency Confidence Report: Low Rolling Resistance Tires” which states “According to SmartWay, the threshold is set at a level that reduces fuel consumption by 3% or more relative to the best-‐selling new tires for line haul tractor-trailers.” I could not find any other EPA source containing an elaboration on the three percent figure, nor could I find which tires were the baseline tire for the comparison. Even as NACFE’s report cites the 3% criteria, their report also cites the SmartWay Verified Low Rolling Resistance Tires Performance Requirements as one of its sources. It is conceivable that the two sources are stating the same increase in efficiency in different ways.
Either way, the tires on this list DO need to meet minimum criteria for rolling resistance. What these tests don’t measure is, well, EVERYTHING ELSE that you might want to know about a tire while picking it. More on what those things might be later.
Now that I had my list, I built it out trying to identify everything I could uncover about each company and any parents or significant owners. Using the magical Internet and the fabulous Google Machine, I assembled the Enhanced Table of EPA Smartway Verified Low Rolling Resistance Tires.
Smartway Verified Tires and the Companies That Make Them
Immediately, I realized that my first version of this document would not be my last – there was simply far too much I didn’t know about commercial tires let alone fuel efficient truck tires to get it right on the first shot. And second, what in the world were all of these tire brands? Recognizing the big, obvious ones were easy; Goodyear, Michelin, Bridgestone, Continental, Dunlop, Firestone, Yokohama, Kumho, Sumitomo, Toyo, and BF Goodrich. I have bought many of these brands for my cars for years. But Rockstar Tires? Double Happiness Tires? BRFriend (BEFriend) Tires?
Wading into the world of tire “Tiers” was the answer to the mystery-name conundrum. In the tire world, tire Tiers break down roughly into three groups based on company size and age, perceived (or real) product quality, regional or global marketing, and tire price; although there are alternative thoughts on the three Tier system.
So a quick generalization is this; every name I recognized is either a Tier 1 or Tier 2 company, and every other name in my database is a Tier 3 brand (or Tier 4 or 5 if you subscribe to more Tiers).
As of mid-December 2015, EPA’s Smartway Verified Low Rolling Resistance tire list contains contains 234 new tire brands*. Many of those brands are made / owned by the same parent company, but pinning down the actual number of LRR tire manufacturers and unique tires is difficult without having actual tires in hand. Because without the tire, you are without the manufacturing plant code which could then be traced back to a specific company. Yes, every tire manufactured or imported into the the United States is required to have a plant code on it so recalls can be done more quickly and efficiently, leaving fewer dangerous tires on the road once bad tires are discovered.
Adding to my not being able to examine every LRR truck tire is the messy complexity of tire making. At least one third of the world’s tire factories, and probably three quarters of the world’s tires, are now produced in China. Add to that:
- Except for a few companies, tires made by the same company are often made in different factories and often by contractor tire manufacturers. Sometimes even the same tire is made in a different factory and by a different manufacturer.
- Not only do these these contract business relationships change over time, but in China, local, city, province and state government involvement and ownership blends with private ownership in complex and murky ways.
- Variation in copyright and accepted business practice from established norms in China versus the industrialized world creates some interesting side effects including the existence of brand names very similar to established global tire and automotive brands (Toyo vs Toyomoto vs Toryo and Bridgestone vs Bigstone) and Chinese brands copying tire tread look and feel (if not actual performance).
- Most Chinese websites, if they exist at all, are translated poorly, if at all, into English. Few of the Chinese LRR tires have their own product pages, and if those pages are available at all, they seldom include product information like tread depth, treadwear mileage estimates or warranties, and are often, are even hard to assign to specific companies and/or manufacturers.
- Brand ownership and online tire purchase information lacks any clarity. Google some of the tire Chinese brands and try to figure out who actually makes the tires versus who is just reselling the tires. In fact, try to figure which company is actually selling the tires versus just selling referrals, reselling tires from another source, or trying to syphon business away from their competitors and sell you other brands of tires. I spent months trying to get to the bottom of this with little success. Visit Alibaba and other Chinese ecommerce outlets and type in the name of an odd Chinese brand; how can thousands of tire sellers be selling the same brands of tires, particularly ones with little brand presence coming out of a single factory in Qingdao, Shandong Province, China?
Highlighting the above uncertainty are the high number of tires with the same exact model number, or containing the same model number and varying by just a one or two letter prefix. Most of these doppelgangers are added to the Smartway Verified list at the same time, or in “familial” groups. That phenomenon plus the fact that the brands often appear associated on the Internet leads me to believe that most of the duplicates or near duplicates are the same tire. Some examples include:
- Model DSR266 is sold as Akuret (DelNat), Aosen, Doublestar, Dongfeng, and Topstar.
- Model HS205 which is claimed by Aeneas, Hongtu, Huasheng, Humsun, Jinxin, Jinyu, Legion, Road Scenery, Taitong, Terraking and Tudor. And my money is on other 205 containing tires being the same tire such as Kebec’s KB205, Multitrac’s XTRAC205, National Gold’s SG205, and Toyomoto’s Trans205. This means that a possible 22 separate tire models may be the same tire, probably all manufactured by Sailun Group Co Ltd. The same bet applies to many other Sailun associated models e.g. HS219
- Models with 678 in the model name include Amberstone, Annaite, Grandstone, Gremax, Guangda, Guobao, Hualu, Hilo, and Qiangwei.
- Companies producing a model D801 include Archron, Aoteli, Rapid, Three-A and Yatone and Yatai. These tires are probably manufactured by Shengtai Group Co. Ltd. Similar probable duplicates exist containing the suffix 801 e.g. S801.
- Amberstone added model 660 at same time as others brands added models containing 660 including Chilong, Gremax, Guobao, Hilo, Hualu, Huger, Milestar, Milever, Qiangwei, Sunny, Turnpike, and Wanli; all probably made by the Xingyuan Tire Group Co., Ltd. Similar duplicates exist containing 606 and many, many other number six (6) containing tire models.
- Models with 728 are offered under seven brands (but only one or two companies) including Haida, Copartner Akuret, Aosen, Topstar, Dongfeng, and Doublestar. Qingdao Doublestar makes at least a few of these models if not all of them.
After spending some quality time crunching the numbers in a spreadsheet, Smartway Verified tire statistics are the following. The raw count of LRR models on Smartway’s tire list is about 1,045; that is without correcting for the probable duplicate model numbers mentioned above. Eliminating duplicates gives us about 690 fully uniquely numbered and/or named tire models.
If one estimates that each unique model is made in an average of five sizes, there is an estimated 3,450 individual SKUs, or model and size combinations, of Smartway Verified LRR tires.
My best analytical guess is that there are 100 LRR Tire manufacturers and certainly between 40 and 125 manufacturers on the Smartway Verified list.
Research did allow me to rediscover things that I might have known long ago. For example, larger tire companies own brands that they use to fill multiple Tiers e.g. Tier 1 Bridgestone makes Tier 1 tires under its own name and under the Firestone (Tier 2) and Dayton (Tier 3) brands as well.
While my research helped establish company nationality e.g. Michelin is French and Kumho is Korean, it didn’t do as much to establish “tire nationality” and whether the tire has serious product research and quality materials inside of it. For example, many small US tire companies are simply Chinese tire importers with their own “brand” stamped on the sidewall of the tires.
While more than a third of all tire manufacturing plants listed in the USDOT database are Chinese (as of July 2015), over 90 percent of the brands on the EPA Smartway Verified list are Chinese brands and /or made in China.
One last note on Chinese brands. Of all the basic numbers, the number four is significantly underrepresented in Smartway Verified tire model designations, with that number used less than half as often as the next most common number; see the numeric model distribution below:
Every Use of the Numbers 0-9 in Naming and Numbering of Truck Tire Models
This four avoidance is probably due to Chinese numerology and numeric superstitions. The number ‘four’ is pronounced similarly to the word ‘death’ in Mandarin and Cantonese, the two main dialects of Chinese. Thousands of years of lingual reinforcement – the written Chinese language is three thousand years old and six thousand years old as a spoken language – has resulted in Chinese corporate hesitation in using the number four in many everyday activities due to its negative association with death, and certainly not those products that actually involve life and death like the safety of a vehicle via is precious tires.
This fear of four, or tetraphobia, also exists less intensely in other Asian countries including Korea, Japan, and due to high Chinese populations, much of southeast Asia. Not only are most of the brands on the Smartway list Chinese – 219 of 234 or 94 percent as of mid-December – but nine of the non-Chinese brands are from tetraphobic Asian countries. Finally, it is not inconceivable that global tire manufacturers avoid the number 4 in their models given their desire to sell to the over 20 percent of global population that is potentially tetraphobic.
Choosing Commercial Truck Tires
When choosing anything as complex and important as tires, seldom should that choice be done via single criteria. Why is this? Because if, for example, fuel efficiency were the only criteria for choosing tires, drivers should run the baldest tires possible, with as little tread as possible. After all, all else being equal low tread tires will get better mileage due to reduced flex, stretch and “squirm” by the tire tread which is now not as tall (deep). Clearly, other considerations need to be taken into account.
Answers to three questions should lead your way to picking your rig tires:
- Where and how the vehicle will be used i.e. short or long distances, types of environments
- Understand all of the factors important to your fleet’s mission, with the most important ones at the top of the list i.e. cargo sensitivity, delivery timeliness, energy efficiency
- Ask how the tires you are using fit into how you accomplish your fleet’s mission 5
Since I am not a tire professional and do not play one on television (yet), you should do additional research before working with your tire professional to select the correct tires for your rig. But forewarned is forearmed and research will allow you to make better decisions.
While there are dozens of speciality types of trucks and trucking applications, five of the most common categories, along with their needs can be seen in the Types of Trucking table below (table scrolls right):
|Trucking Type||Service Type||Roads Conditions||Job Distances (miles)||Annual Distances (miles)||Tire Wear Type||Desired Tire Traits||Notes|
|Long Haul||Highway speed, low variation||Highways||300 +||100,000 +||Low abrasion||Long tread life, high efficiency||I bet long haul truckers would argue that base distances is higher|
|Regional||Medium haul||Primarily highways, some secondaries||up to 300||30,000 - 80,000||Medium abrasion, increased lateral scrub||Good combination of long tread life, scrub resistance, high efficiency||Line haul often included in urban and / or regional|
|Urban||Start-stop duty work in city traffic, high variation||Urban streets||Local, within region / state / city limits||under 30,000||High abrasion, constant twisting and turning||Heavier duty tire resistant to scrub||High scrubbing environment, high ratio of tight turns during duty cycle|
|Coach / Bus||Long, medium and short haul, carrying passengers||Varies by operator, from highway to regional secondary roads and urban city streets||City limits to cross country||80,000 - 100,000||From low abrasion to high abrasion depending on duty type||Depends on duty type; see long haul, regional and urban categories for trait recommendations||How do tire needs differ for non-articulated buses / coaches?|
|On / Off Road / Construction||Medium and short haul, typically work vehicles (dump trucks, bulk haulers, service vehicles, equipment and materials delivery)||Both on-road and off-road including gravel, sand, dirt, and rocky conditions||up to 100||10,000 - 70,000 miles||High abrasion, exposure to aggressive surfaces and environments||Chipping, cutting and puncture resistant||Rock drilling of tires is important to monitor|
Adding the considerations from the above to a few others gives us the following list of tire attributes which can be used in choosing the right truck tire:
- Tire cost
- Tread life
- Fuel efficiency
- Tire retreadability
- Tire life cycle cost (fuel efficiency, tread life, tire cost, timing of tire removal based on tire quality, equipment cost and tire maintenance costs, retreadability)
- Damage resistance
- Scrub and curb resistance
- Cut, chip, gouge resistance
- Lower tire and wheel weight (for increased payloads, increased legally travelable roads)
- Load shifting and damage due to tire issues
- Time off of road
- Timeliness requirements and reduced pay due to load lateness
- Ride comfort and lower noise tire
- Missed timing on next loads
- Loss of current or future jobs
- Even wear (mentioned mostly for lower quality tires)
- Blowout resistance (mentioned mostly for lower quality tires)
- Disappointment (with tire cost, tire life, load damage, etc.)
Donn Kramer via Evan Lockridge in Trucking Info put it well when he writes “Fleets should target a balanced performance package, such as fuel economy, miles to removal, start-and-stop traction, casing retreadability, safety and price,”
A few overarching principles that seem to be of value to truckers based on my research include:
- Don’t buy cheap tires for your steer tires. A blown drive or trailer tire is annoying and sometimes problematic, but a blown steer is often epically bad.
- After selecting and mounting a tire, tire pressure monitoring and maintenance is the single most important action one can take for maintaining a safe, long lasting tire.
- Beyond tire pressure, other monitoring and maintenance are key to a reduced-problem driving experience. Examining your tires for damage, bulges, tread oddities or uneven treadwear is crucial. Rotate your tires regularly to keep wear regular. Get regular truck check-ups to identify problems which can shorten your tire life and worse.
- Inexpensive (cheap) tires may be quite expensive in the long run if replacement, fuel efficiency and ride quality and safety are significantly reduced. A $150 tire which gets 100,000 miles ($0.0015 a mile) is more expensive than a $250 tire which gets 200,000 miles ($0.00125 a mile), all else being equal. And often, the more expensive tire by price tag is less prone to failure and has a better warranty.
- Drive like a hypermiler and increase the life of your tires by double digits. That means no jack rabbit starts; no rapid, hard braking stops; no tight and hard turns, particularly at higher speeds, and no exposure to curbs, rocks and other off road conditions. All of these reduce the life of a tire.
- Keep records on your tires, it will pay off later. Record the brand, size, shop that did the work, condition of the tire, repairs and dates, miles on tire at each position, and condition and reason for removal. If tire is retreaded, record retread shop, retread technology, and everything else you were tracking for the new tires. This will tell you about which tires suit you and your truck best. And it might help you diagnose underlying problems with your wheel and chassis system if a particular tire location keeps creating tire problems.
- Perform some simple math to understand the cost of more or fewer tire changes, rotations, mountings, roadside assistance calls, and so on. For example, use real or good estimated prices to calculate what one fewer roadside assistance calls every two years would do to your cost if you had purchased a better tire. And if your tire guy can help, lean on him for help with the calculations, too.
While you should make sure you are not giving up crucial tire features, making your job more dangerous, uncomfortable or costly, the availability of high quality multi-function low rolling resistance tires for all positions (steer, drive, trailer) and most applications means that there is little reason NOT to buy low rolling resistance tires as replacements for your vehicles. Just hesitate before buying the cheapest tire you can find; you may find it is one of the most expensive you have ever purchased.
1 – Original version:
For want of a nail the shoe was lost.
For want of a shoe the horse was lost.
For want of a horse the rider was lost.
For want of a rider the message was lost.
For want of a message the battle was lost.
For want of a battle the kingdom was lost.
And all for the want of a horseshoe nail.
Updated by Pure Oil Company, advertisement from LIFE magazine Mar 2, 1942, brought to my attention by Wartime: Understanding and Behavior in the Second World War By Paul Fussell P 168 Copyright 1989 Oxford University Press via Google Books.
For want of a tire the car was lost
For want of a car the man was lost
For want of a man the job was lost
For want of a job the bomber was lost
For want of the bomber the battle was lost
2 Which is why rolling resistance is is expressed as the ratio of the force needed to keep a tire rolling to the weight at the spot where the tire meets the road (its contact patch).
3 The Smartway list applies to “low rolling resistance tires are SmartWay verified when used on class 8, line-haul tractor trailers”
4 Two more descriptions of Smartway from the same document that do a good job are: “Smartway Transport is comprised of partnerships, policy and technical solutions, and research and evaluation projects that find new ways to optimize the transportation networks in a company’s supply chain” and “SmartWay Transport Partnership is a strong government/industry collaboration between freight shippers, carriers, logistics companies and other stakeholders, to voluntarily achieve improved fuel efficiency and reduce environmental impacts from freight transport”
5 Three main considerations with modifications from Paul Crehan via Evan Lockridge in http://www.truckinginfo.com/article/print/story/2013/03/tires-for-multiple-applications.aspx
* There are additional precure retread and mold cure retread brands that are not included in the tire tabulation in this report.