Tag: tires

Posted on

Mickey Thompson Baja Boss A/T LT255/85R17

Mickey Thompson Baja Boss A/T LT255/85R17

The Baja Boss A/T was introduced to automotive journalists during the virtual 2020 SEMA Show with a press embargo date of April 5, 2021. After the embargo Mickey Thompson sent me a set for a long-term evaluation, which was published in the Turbo Diesel Register magazine. For my initial review I chose a popular 18-inch size aiming for the broadest appeal for those with newer trucks. In that piece I shared that Mickey Thompson introduced a new niche size, the LT255/85R17, that I also wanted to evaluate. 

LT255/85R17E is a cool, new, niche size.

Overview

The Baja Boss A/T is a fairly high-void, four-rib tread design that Mickey Thompson calls a hybrid, AKA a commercial traction or an aggressive all-terrain. Absorbed by sister brand Mickey Thompson a few years ago, the legendary but now defunct Dick Cepek company arguably invented the first hybrid tread in 1978, when Mr. Dick Cepek introduced the first Fun Country. This was long before anyone used the word hybrid to describe tires, and before several other manufacturers started emulating these versatile and multifaceted designs. 

2014 version of the Dick Cepek Fun Country.

When compared to a more conservative all-terrain or all-season, the deeper and higher-void tread offers better resistance to hydroplaning and superior grip on deeper snow and moderate mud. These attributes are often combined with rugged carcass construction, and if the right special sauce is used for the tread compound sometimes they also offer superior longevity. 

Continually reducing road noise while improving other benefits of traction designs is a challenge for engineers. Historically there’s been no easy solution, because better traction in sloppy conditions requires bigger blocks and voids, which increases road noise. The Baja Boss A/T is quieter than it looks. 

Mickey Thompson’s Baja Boss A/T has been a favorite since its 2021 introduction.

According To Mickey Thompson

Mickey Thompson says the Baja Boss A/T blends Extreme Sidebiters® for a bold look and serious grip with an all-new silica-reinforced compound providing long-wear, all-weather performance and cut/chip resistance.

Design highlights include:

  • Large surface-area tread elements for a greater contact area
  • Shoulder scallops for an additional biting edge
  • Sound-deadening ribs for stability and a quiet ride
  • Enhanced stone ejectors to reduce debris retention
  • PowerPly XD™ with 50 percent heavier denier cord on the biased-angled third ply for protection, handling and stability
  • Rim flange protector for added wheel protection
  • 3 Peak Mountain Snowflake (3PMS) symbol certifies that all sizes 12.50 (315mm) and narrower are Severe Snow Service rated
  • 50,000-mile treadwear warranty
  • Increased-load LT-Metric sizing for heavy-duty applications
  • Lower-load floatation sizing for half-ton, lighter trucks and SUVs  
  • A 35-inch tire approved for 17×6.5 dually wheels 

That last bullet point is the specific size this review is about, the LT255/85R17 Baja Boss A/T (also know as the 35×10.00R17LT). The substantial siping helps achieve the severe winter rating and increases overall grip, and measures a whopping 17/32” of the total 18.5/32” depth. Calling the sidewall rubber Extreme Sidebiters® is not an exaggeration, as they are up to 14/32” thick!

Extreme Sidebiters® on the LT255/85R17.

LT255/85R17 For Duallys

Dual Rear Wheel (DRW) pickups have an import role in the heavy-duty market, above the more common and very capable single rear wheel (SRW) HD trucks, but a notch below what are really medium-dutys, the 4500 and 5500 chassis. But the rear duals greatly restrict aftermarket tire options due to the spacing needed between sidewalls. 

Unless someone wants to have their outside tires protruding well beyond the fenders (some do, and they think it looks cool), the DRW crowd has few choices for taller rubber that will fit otherwise stock or lightly-modified trucks. Mickey Thompson invented the new LT255/85R17 size to fill this niche. It is 35-inch-tall (34.6”), and was purposely designed to fit narrow 6.5-inch dually wheels, though it works well on wheels up to eight inches wide for SRW pickups. 

When inflated to 80 psi, the 121 load-index supports 3,195 pounds each in SRW applications, or 2,910 pounds for duals. The tread has one nylon, two steel, and three polyester plies, the sidewall construction has three polyester plies, and they are made in the U.S.A. 

Single Rear Wheel Use

Narrower tires will almost always clear more easily with fewer and sometimes zero modifications than a wider tire of the same height. What is also routinely overlooked because many are focused on looks, and wider is perceived as tougher and better, is that a narrower footprint usually rolls down the road more consistently, catching fewer edges, rain grooves, or semi-truck ruts. There are some people that still prefer the appearance and performance of moderate width tires (few modern LT tires are actually narrow or small), and avoid negative-offset wheels or grossly wide rubber sticking well beyond the fenders, which sling rain, snow, mud and other debris. 

So it was not surprising to hear Senior Project Manager, Light Truck Division at Mickey Thompson, Ben Anderson, say that the Baja Boss A/T in LT255/85R17 has become popular with the Jeep and Toyota crowd, and others wanting taller but not needlessly wide off-road meats for their four-wheel-drives. I’m also one of those folks. 

Confirming Mickey Thompson’s stated height of 34.6”. Tires are measured when mounted on a specific rim width, but not on a vehicle. Those complaining that tires are shorter than advertised when loaded by a chassis are uninformed.
LT255/85R17E section width is 9.8”. 

Sidebar

17-inch Tires Limited to 3,195 Pounds

Why are most heavy-duty seventeens rated to support much less weight than a similar 18-inch, or even less than the same 17-inch size was in the past? Nearly all new 17-inch light-truck tires are limited to a maximum capacity of 3,195 pounds regardless of their size, psi, or theoretical capabilities.

It appears that several years ago the Tire and Rim Association (TRA) decided to lower the maximum load index for seventeens. Or maybe there was a government regulation necessitating the change? Whatever the reason, it is difficult to find high-capacity 17-inch rubber. 

The official TRA load inflation charts indicate that something doesn’t compute. For example, the LT295/70R17E has 3,195 pounds of capacity when inflated to 65 psi. However, increasing the pressure to the maximum allowable 80 psi offers no increase in capacity. My basic understanding of math and science tells me that this is not how pressure and volume works inside a tire. Plus there are exceptions to the 3,195 limit. 

3,970 Pound 17-Inch Anomaly

I think that if a specific tire design and/or size existed before the change, that manufacturers were grandfathered. Specific examples can be seen online, including from Toyo in their Open Country M/T line. Still using LT295/70R17E, the Toyo M/T has a load index of 128, and is rated to support 3,970 pounds at 80 psi, which makes much more sense. That is a whopping 775 pounds more than 3,195, and 1,550 pounds or 3/4-ton per axle! 

For a given diameter, smaller wheels yield taller sidewalls, generally flex more, and may generate extra heat. Excessive heat is the archenemy of tires, so I theorize that this was one reason to push folks to bigger rims. 

Yet there are big 16-inch sizes rated above the 17-inch, 3,195 maximum. The LT305/75R16 is rated for 3,640 pounds at only 65 psi. What gives? Are you a tire engineer reading this article? If so and you want to share some industry knowledge and history, I’d love to hear from you. 

Possible Solutions

Many newer pickups come with 18-inch or larger wheels and there are many sizes that offer excellent carrying capacity. However, there are plenty of older trucks still running around on their original 17-inch rims, and they might need more capacity when hauling big loads. Proceed at your own risk, you are your own warranty station, nobody is responsible but you, etc. Depending on the specific tire, size, and manufacturer, and how one applies the science, it is possible that you may already have, or could source a 17-inch tire with more capacity than 3,195 pounds.

Mount And Balance 

The Baja Boss A/T tread is asymmetric and there is a dedicated inside and outside sidewall, so they should be mounted correctly. It is possible to have a tire and wheel that is balanced according to the machine, but drives poorly. One reason can be attaching excessive weight to achieve the balance, and road force is another. As discussed in a previous article, excessive road force, or radial force variation, is a condition that can affect steering, traction, braking and load support. High road force will impart ride disturbances to the chassis and ultimately the driver. 

Baja Boss A/T is an asymmetric design, with dedicated outside and inside sidewalls.
Discount Tire was hired to do the mounting and balancing.

Both the wheel weight required and the road force measurements were extremely low for this set of Mickey Thompsons. An acceptable maximum road force measurement for passenger car tires is 35 pounds, but all of these Baja Boss A/Ts were in the teens, which is phenomenal for a stout light-truck tire weighing 64 pounds. They were mounted on 28-pound OEM Fourth Generation 17-inch Power Wagon wheels, and the average weight needed to balance the resulting 93-pounds was only 3.9-ounces! 

#1- 4.5 oz., road force 17-lb 

#2- 3.75 oz., road force 11-lb 

#3- 4.00 oz., road force 14-lb 

#4- 3.25 oz, road force 16-lb 

Data is nice, but like with many things these days we must ensure that the machines are accurate and confirm for ourselves that everything is truly working well. 

Got road force? Hopefully not too much. These were perfect.
93 pounds for a modern wheel and aftermarket tire is in the normal range, but the size of the wheel and tire matters. I have a set of 20 inch tires and wheels that weigh 111 pounds, 20% more!
Wheel and tire #1 needed the most wheel weight, but that was still only 4.5 ounces.

Take It To The Limit, One More Time

My initial seat-of-the-pants freeway evaluation confirmed that Discount Tire’s balance machine was calibrated. These 255/85R17 Baja Boss A/T were fantastically smooth all the way up to 100 miles per hours and straight line tracking was excellent. I was running 58 psi in the fronts, and 40 psi in the rears, plenty for my 2500’s everyday unloaded wet weight. 

The Toyo C/T is a similar heavy-duty commercial traction design and one of my all-time favorites, and a set was removed to mount the Mickey Thompsons. While the C/T are not loud for their capabilities, the Baja Boss A/T are noticeably quieter.  

With low road force and minimal wheel weight, it wasn’t surprising that these LT255/85R17 Mickey Thompsons remained smooth at all speeds.
Baja Boss A/T were mounted on a set of used, scratched, but still true Power Wagon wheels. The same rims traveled up to the frozen Arctic Ocean at Tuktoyaktuk, Northwest Territories, Canada, in 2017.

Not Loud

The lack of noise from the Baja Boss A/T for the amount of void and traction impressed me back in 2021. There are similar, older treads that I still like and have run extensively in multiple sizes on several four-wheel-drives, and the Cooper Discover S/T MAXX is a great example. The S/T MAXX is a little louder when new, but once they are worn the volume increases substantially, sometimes becoming nearly as loud as a mud-terrain. The Baja Boss A/T starts and remains quieter than others, and the engineers really deserve credit. Are they as quiet as a five-rib A/T or highway tread? Of course not. As with all tires, to help reduce noise and keep your rubber wearing evenly, frequent and consistent rotations are necessary. 

Ride Quality

What constitutes a good or poor ride characteristic depends on one’s performance perspective. Some prefer a softer and more compliant on-road ride, while others want or need firmer and ostensibly stronger options. Even within the LT tire category there can be huge differences between tread designs and carcass construction, even when the load index and other ratings are identical. The Mickey Thompson Baja Boss A/T is sturdy, which I prefer when using my pickup for hauling, towing, and rugged off-pavement use. The PowerPly XD™ with its 50% heavier denier cord and biased-angle third sidewall ply can be felt, but that’s to be expected and is appropriate for the intended applications.  

I do prefer a somewhat softer ride during normal daily driving, but this is easily accomplished with the following two practices. I don’t combine super tall wheels with short and silly thin sidewalls (which also reduces carrying capacity), and I run close to the minimum pressure required for the weight on each axle. This means I know what my vehicle weighs, find the appropriate psi using an inflation chart, and am diligent about adding air when the load is substantially increased. 

How Low Can You Go?

When unloaded I routinely run my rears between 35 and 40 psi for comfort, traction, and overall performance. The fairly soft riding 2014-and-newer Ram 2500s are not nearly as rough as the older and stiffer suspensions, but it’s still suboptimal to have overinflated tires. The ride quality difference between 80 and 40 psi with no load on the rear axle is dramatic. Over-inflation hurts grip and uneven wear is also possible. 

Depending on the exact size, load index 121 tires will have a capacity of about 1,950 pounds each, or 3,900 pounds per axle at 35 psi, more than many think. One can always increase pressure to tune for their speed, ride, and overall preferences. Tires get hotter in warm weather and at higher speeds, and overheated tires can and do separate. Increasing psi for certain conditions might be desirable, but that doesn’t mean jumping from 35 psi to 80 when there is only 3,500 pounds on the axle. 

In the front I typically run between 50 and 60 psi depending on the ratings and weight. The Cummins Turbo Diesel is heavy, but front axle loads are less variable so pressure adjustments are rarely needed. 

60 psi up front and 39 psi on the rear axle is plenty for my truck based on the Tire and Rim Association load information charts. Your circumstances may be different.
Off-pavement crawling pressures, and much too low for regular driving. Note my minimum psi thresholds, 48 in front and 28 in the rear. These lower thresholds keep the TPMS light off unless there’s a leak and pressures are dangerously low, which is my preference. (Water-in-fuel light was triggered by a car wash.)

Light Load TPMS Light

The federally mandated Tire Pressure Monitoring System (TPMS) is an outgrowth of the Ford Explorer/Firestone debacle in the 1990s. It’s also symbolic of a larger problem, which is the unwillingness of the average driver to take responsibility for their machinery, including failing to check something as fundamentally important as tire pressure. Even with TPMS on my pickups, I regularly check and adjust pressures with a handheld gauge. 

Having psi information available on the dash is great, but it’s unfortunate that Ram eliminated the light-load option around 2012, and require all 2500 owners to run pressures for maximum loads or accept a warning light on the dash. The 3500 Rams have a different system, the Tire Pressure Information System (TPIS), because their GVWR is over 10,000 pounds. TPIS provides information but does not force a warning light for running less than a predetermined and maximum pressure. 

I permanently eliminated the TPMS irritant with a professional Autel MaxiSys MS906 tablet scan tool. One could argue that this was a $1,000 sledgehammer solution to dispatch an ant. True, but I purchased the Autel one year before the AlphaOBD diagnostic software was available, which reportedly works well for adjusting the pressure thresholds. 

A professional automotive tablet is a super powerful diagnostic tool, and I have only used a small fraction of its capabilities. But the scanner has come in handy a few times by allowing me to discover the source of unusual problems or clear codes that were too much for my Edge CTS2. 

Regardless of the tool being used, I absolutely love being able to adjust the minimum psi thresholds for both the front and rear axles to my liking, depending on the load index of the tires and my needs. My 2017 regular cab has a heavy Hallmark flatbed camper mounted full-time and the rear axle threshold’s are set higher, usually around 70 or 80 psi. 

Autel tablet allows adjustment of the TPMS sensor thresholds and so much more.

Need Traction?

Traction, handling, and overall performance from the Baja Boss A/T has been impressive in all conditions and on every surface, which has included considerable dirt, gravel, rock, rain, and snow. For those wanting hybrid or commercial traction rubber I don’t envision many people wanting more grip over varied terrain than these Mickey Thompsons provide. My first set of Baja Boss A/T saw less snow than I would have preferred, not taking advantage of the three peak mountain snowflake (3PMS) rating because our local Sierra Nevada winter storms and my travels rarely overlapped in 2021. The story is dramatically different with the second set. 

Got Snow and Rain? Lots Of It?

The day after mounting these LT255/85R17 on my 2014 crew cab, I made a 500 mile weekend round trip that included two crossings of the Sierra Nevada’s infamous Donner Pass. There were several inches of wet snow for dozens of miles that required four-wheel-drive. Followed by 100 miles of epic rainfall. The kind of rain that even with the windshield wipers bouncing at full speed I could barely see the roadway, similar to dangerous fog conditions, and using four-wheel-drive was beneficial because of water on the road. Throughout the remainder of winter and spring 2024, the Baja Boss A/T performed perfectly during every winter storm. 

Similar to mud, the types of snow and the related driving conditions can vary greatly by region or microclimate, and opinions regarding what is good performance in certain conditions are highly subjective. For my uses I have found that the Mickey Thompson Baja Boss A/T are an excellent winter and wet weather performer under my Ram 2500. 

These Baja Boss A/T have seen much snow and performed flawlessly.
Higher-void and deeper treads can perform well in heavy rain because the water can escape instead of being trapped under the tire.

Sidebiters®

Sidewall tread has become popular in recent years, even on tires that are really not intended to be used in harsh off-pavement conditions because it looks cool. However, the Baja Boss A/T Extreme Sidebiters® are legit, and are super thick and beefy. I certainly like how they look, but also put them to work for their intended purpose. If you never leave the pavement, the Sidebiters® aren’t going to complain if you drag them along curbs.  

Using the Sidebiters® for their intended purpose. Low psi deformation allows a tire to conform to obstacles and improves traction.

Estimated Longevity Baselines

Wear and longevity for a given tire can be highly variable depending on the vehicle, duty-cycle, and driver. One could argue that all three of these metrics (and others) are important, however, the person behind the wheel has a disproportionate effect, and will invariably influence results dramatically compared to the others. 

If we were to take two identical pickups (model, gearing, transmission, tires, etc.), load them the same, and run them over a route with different drivers, it would not be surprising to see measurably different fuel economy. Covering longer distances and varied terrain would make the differences more obvious. More or less mpg is a direct result of how one operates the accelerator and brakes. 

Tires and brakes are consumed more slowly than fuel, but over time the driver who gets fewer mpg and exercises less finesse and vehicle sympathy will likely also get fewer miles out of their rubber and brakes. The differences can be dramatic. 

Same Guy Driving The Same Truck

No one’s truck, conditions, or driving style are identical, however, if the driver is not one of the variables the data can be more comparable. The treadwear information I’ve gathered from several four-wheel-drives over decades, particularly during the last 10 years driving the same 2014 Ram 2500 crew cab with a G56 6-speed manual transmission, provides relatively consistent and relevant information. 

Wear Data

These LT255/85R17 Baja Boss A/T were mounted February 2024, have been rotated twice, and have logged 6,300 miles. Approximately 10% of those were off-pavement, including dozens at low trail pressures to improve ride, traction, and prevent damage. There is zero visible cutting, chipping or lug tearing of the tread, which is impressive considering the amount of off-highway use my truck sees. (Again, driving habits matter, and I keep tire slip and spinning to a minimum, particularly in the dirt.) 

While I am smooth and conservative off-pavement, on the blacktop I routinely use all of the torque, horsepower, and rpm that my G56 version of the Cummins 6.7L has to offer with assertive application of the skinny pedal. Just like hard braking and turning fast can disproportionately wear the fronts, the massive twist of modern diesel engines can be hard on the rear drivers. Yet, that is not what I’ve experienced, there has been no penalty for my lead foot. 

All Baja Boss A/T come with 18.5/32” of tread, and this set currently has about 15.5/32”, so they have given 2,100 miles per 1/32”. Those 2,100 miles compare well with other quality aftermarket traction designs, on the same truck, driven by me. 

Deeper tread generally helps with traction and increases longevity. All Baja Boss A/T sizes have 18.5/32”.

For comparison, my previous set of Baja Boss A/T in 295/70R18 were run for 15,000 miles and delivered 2,300 miles for each thirty-second before they started living on a friend’s 1991 W250 Turbo Diesel. If 2,100 miles per 1/32” remains constant, these 255/85R17 Baja Boss will last 36,800 miles before reaching the minimum legal depth of 2/32”. 

Baja Boss A/T is a quiet traction tire that looks good and performs extremely well, both on and off-road.

Still Love Them

After running two sets of Baja Boss A/T over the past few years I’m still enamored with this design from Mickey Thompson, and it might become my favorite hybrid all-terrain. They wear well, provide excellent traction and performance in all conditions, and are extremely rugged while still being quieter than competitors. Currently they are available in 74 sizes, for wheels from 15 to 24 inches. If you are in the market for a new set of tires you owe it to yourself to consider the Baja Boss A/T from Mickey Thompson. 

Riding off into the sunset in my 2014 Cummins Turbo Diesel.

Tell ‘em you saw it on RoadTraveler.net!

Copyright J. Langan/RoadTraveler. All Rights Reserved

Resource: 

Mickey Thompson Tires: mickeythompsontires.com 

 

Posted on

Mickey Thompson Baja Boss A/T LT295/70R18

Remote, northeast corner of Nevada, near the Idaho and Utah borders, BLM managed public land.

Mickey Thompson Baja Boss A/T LT295/70R18

During the November 2019 SEMA Show, I received insider information from a Mickey Thompson manager about a new Baja Boss A/T they had in-the-works; it was still more than one year from being announced. I’m a fan of the Benjamin Franklin quote “three may keep a secret if two of them are dead,” and I focus on being the one that is alive. 

The Baja Boss All-Terrain was introduced to automotive journalists at the virtual 2020 SEMA Show, with a press embargo date of April 5, 2021. As soon as possible I requested a set for evaluation, choosing the LT295/70R18 size. One month later I had them.

Long-term Mickey Thompson’s Baja Boss A/T evaluation started April 2021.

As you can see in my photographs this is a fairly high-void, four-rib tread pattern that Mickey Thompson calls a hybrid, AKA a commercial traction design or an aggressive all-terrain. Tires like these have been my preference for decades, offering more potential grip via siping, self-cleaning abilities, and deeper tread than more conservative all-terrains or all-seasons, while offering a quieter driving experience, and better longevity than mudders. 

Continually reducing perceived noise while improving the other attributes of these hybrid designs has been an ongoing challenge for engineers. Historically there’s been no free lunch, because much better sloppy conditions traction requires bigger tread blocks and voids, increasing road noise. Was Mickey Thompson able to achieve the impossible? Read my opinion about this below under the subheading Quiet? 

There’s much to like here.

According To Mickey Thompson

Mickey Thompson says the Baja Boss A/T blends Extreme Sidebiters® for a bold look and serious grip with an all-new silica-reinforced compound providing long-wear, all-weather performance and cut/chip resistance.

Design highlights include:

  • Large surface-area tread elements for a greater contact area
  • Shoulder scallops for an additional biting edge
  • Sound-deadening ribs for stability and a quiet ride
  • Enhanced stone ejectors to reduce debris retention
  • PowerPly XD™ with 50 percent heavier denier cord on the biased-angled third ply for protection, handling and stability
  • Rim flange protector for added wheel protection
  • 3 Peak Mountain Snowflake (3PMS) symbol certifies that all sizes 12.50 (315) and narrower are Severe Snow Service rated
  • 50,000-mile treadwear warranty
  • Increased-load LT-Metric sizing for heavy duty applications
  • Lower-load floatation sizing for half-ton, lighter trucks and SUVs
  • Several sizes approved for 12-inch and 14-inch wide wheels, including three 35X15.50 sizes 
  • A 35-inch tire approved for 17×6.5 “dually” wheels 

To all of the above I say yup, appears to be true! The substantial siping, which helps achieve the severe winter rating and increase overall grip, measures a whopping 17/32” of the total 18.5/32” tread depth. Calling the shoulder tread Extreme Sidebiters® is not public relations department hyperbole, as they are 14/32” at their deepest!

Sipes measured 17/32” deep!
Extreme Sidebiters® “for a bold look and serious grip”. Truth!
Up to a whopping 14/32” of Extreme Sidebiter® on sidewalls.

Sizes are offered for wheels from 15-24”. A standout worth noting for the DRW folks or old-schoolers like me that prefer taller, narrower rubber that fits and clears more easily, offering less rolling resistance, potentially better fuel economy, etc., is the LT255/85R17. Also know-as a 35×10.00R17, this load-index 121 size supports 3,195-pounds at 80-psi in SRW applications, and would be great under my everyday crew cab. However, the 129 load-index and 18” wheel of the LT295/70R18 was a better choice for my flatbed Hallmark Camper outfit because the shorter sidewalls are firmer and more stable for maximum loads. 

2017 Ram with Hallmark flatbed camper always works much harder than my 2014 crew cab daily driver.

Mount & Balance 

Unless a specific tire and wheel combination requires a different solution, my standard practice is to use a single plane, so-called static spin balance, as this method requires less weight and is generally sufficient. Wider tires and wheels, super aggressive treads, or just a carcass with more lateral imbalance may require dynamic balancing, which involves putting weight on both the inside and outside of the wheel. 

Many do not realize that it is often the wheel that requires the majority of the weight to balance an assembly, as modern tires are generally fantastically true. An easy way for an enthusiast to see this is by noting where wheel weight has been placed for their current and previous sets of tires. Typically the weight is needed in the same general area, pointing to imperfections in the wheel more than the tires.  

According to Mickey Thompson the LT295/70R18 size weighs 67 pounds each, and they were 104-pounds when mounted to an OEM forged aluminum wheel. Maybe you should sit down before you read how little weight was needed to static balance these beautiful meats. 

1) 3.0 ounces, right-rear

2) 3.25 ounces, right-front

3) 2.5 ounces, left-rear

4) 3.25 ounces, left-front 

Instead of putting the rims with the least weight upfront as is common at most shops, I typically put those with the most weight on the front axle. This helps confirm that they’re truly balanced, and avoids potential surprises after the first rotation. In this instance all the wheels needed just a few ounces. I rarely have tires rebalanced, as Centramatic balancers constantly perform that task. These Bosses have been run up to well above any speed limit on numerous occasions, and they have remained insanely smooth after thousands of miles and a few rotations, living on both of my Ram/Cummins trucks. 

Just a few ounces to balance the LT295/70R18E, which is continually maintained by the Centramatic balancers visible behind the wheel spokes.

Quiet!

Manufactures have been increasingly successful making beefier treads quieter, yet I routinely find that even aggressive hybrid treads that start out impressively tame get louder with wear, sometimes much louder, even with optimal rotations. (All bets are off if proper maintenance and rotations are not strictly observed.) This has not been the case with the new Baja Boss A/T, the barely audible hum has yet to increase. To my ear they are still one of the quietest, if not the quietest, tire in this category that I’ve experienced. Impressive! 

Great looking tread that is also impressively quiet for its void.

Tough Enough? Extreme Puncture Resistance?

Rugged designs help prevent punctures and stout carcass construction helps tires run cooler and support big loads, translating into better performance under heavy diesel-powered rigs that do more than run around empty. Commercial tradesman applications, farming and ranching, off-pavement adventures, and RV users can all benefit from the Boss A/T’s stout construction. Are these treads as rugged as they claim? After over 14,000 miles of hard use, my answer is a resounding yes!

Designed to do work, diesel trucks can be hard on tires. Size can a limitation, but my trucks leave the pavement often, mostly in the high-desert of the Intermountain West.

My tire evaluations typically include a photo shoot off-road at low pressures in a nearby National Forest, where I flex and abuse the tread and sidewall on some rocks. It helps gauge ruggedness and flexibility, and makes for some cool photographs. Few other than dedicated a 4WD enthusiast will ever do this, particularly in a big diesel pickup…enter the James-ness! 

Low pressure tire loading and flexing off-road.

Even rugged tire designs can be punctured, as they are essentially rubber balloons. However, I was thoroughly impressed with the flexibility and ruggedness of the Baja Boss All-Terrain’s when I subjected the tread, shoulder, and sidewalls to folding and pinching rarely seen outside of competitive rock crawling. 

After the photo shoot, they were filled with appropriate street pressure, and have continued to perform flawlessly at all speeds and under all conditions. Tire pressure has been dropped many times to improve off-payment traction, ride, and overall performance, and the tires repeatedly work like they should. 

Extreme Sidebiter® folding and pinching on the right-front tire at low pressure under a 2014 Ram/Cummins crew cab.
Some tires can take considerable abuse, obviously this tire did, but there’s always risk of damage or failure.

Application Considerations

My 2017 regular cab with Hallmark flatbed camper is a full time RV, so while it’s under a constant, full-load, it accumulates miles much more slowly than a daily driver. One would think that a heavily loaded RV-application Turbo Diesel (hauling and/or pulling) would result in rapid wear, yet that is not necessarily what happens. Chronicling treadlife on many sets of tires on my diesel pickups, and those of friends and acquaintances has provided valuable perspective. 

Vehicles that see daily driving are typically subjected to repeated hard accelerations, which loads the drive tires, as well as hard stops and turning, which is harder on the fronts. These realities often contribute to reduced life compared to vehicles that see more steady, long-distance travel.

Occasional aggressive use of the skinny pedal is part of my driving style, although I am extremely soft on the brake pedal and travel slowly through most tight turns. I often obtain superior longevity and slower wear on my daily driver crew cab compared to my friends. Drivers matter. 

Longevity

The Boss All-Terrains were initially mounted on my 2014 crew cab to log miles more quickly. As shared in previous columns, I am highly critical of the brief tire reviews in most magazines that say… the tires performed well, we really like them, blah blah; which is typically the result of nothing more than a few hundred miles of use, not thousands. Occasionally there’s an update later after more miles. Thousands of miles of saddle time and evaluation should be the baseline norm, not the exception. 

The Boss A/Ts arrived at the perfect time, as I had started working away from home; the 2014 crew cab started seeing daily commuting miles, which included a run home during my lunch break for dog care. I’m often pressed for time, and there’s much firm use of the skinny pedal at the hands of the BD Throttle Sensitivity Booster (still LOVE it!). Due to these lifestyle changes the Boss A/Ts received harder use than any others treads in many years. 

Under torque-monster diesel pickups I have repeatedly observed that approximately 1/32” of tread per 2,000 miles is good or average for an aftermarket set of rubber, and substantially more miles, 2,500 or so, is above average. For comparison, a few sets of OE Firestones I’ve measured have melted though 1/32” in a mere 1,500 miles, 25% less than my 2,000 mile baseline! 

After the initial mounting and the first rotation on the 2014 crew cab, I had accumulated 6,500 miles on the Baja Boss A/Ts. Three measured 15.5/32”, and one was 15/32”, which was 2,080 mi. per 1/32” of tread depth. Considering the repeated, aggressive accelerations and fast driving this was above average; it would be just average with less spirited driving. 

The Mickey Thompsons were pulled from the crew cab and slapped onto the 2017 Ram flatbed Hallmark camper rig, where they logged another 4,500 (s)miles before their third rotation. The rears were down to 13/32”, with the front wearing little and still showing 15/32. (This is part of why we must rotate.) As the tread becomes shallower the overall accuracy of measurements increases, and it’s not uncommon for the rate-of-wear to slow after these more accurate measurements. With another 3,500 miles under the Hallmark Camper, 14,500 miles total, all were showing 13/32”. The Baja Boss A/T treads had achieved 2,600 miles per 1/32”, which is well into the above average column for many diesel pickups. 

After hours of slow 4WD, with several narrow and/or technical spots for such a big outfit, it was time to stop treating this rig like a side-by-side and make camp.

Traction Everywhere

Traction and handling has been impressive in all conditions and on all surfaces, which included much dirt, gravel, rock, some sand, rain, but unfortunately very little snow. It would’ve been nice to evaluate the severe winter rating more thoroughly. However, the western states multiyear drought has severely reduced precipitation in Northern Nevada and Northern California. 

It’s difficult to chronicle the exact number of off-pavement miles these Bosses have seen, but a conservative estimated is 1,500 (10% is huge for non-commercial applications). Opinions regarding traction are mostly subjective, variable, and relative to the platform and driver. Nevertheless, for those wanting a hybrid tire I don’t envision people wanting more grip than the Baja Boss A/T can provide. Should the opportunity present itself I’d gladly run another set of the Baja Boss, as they’ve earned a spot on my short list of favorites. 

Tell ‘em you saw it on RoadTraveler.net!

Copyright J. Langan/RoadTraveler. All Rights Reserved

James Langan

Resource: 

Mickey Thompson Tires: mickeythompsontires.com 

 

 

 

draft

Posted on

NEXEN ATX All Terrain Photos

Tell ‘em you saw it on RoadTraveler.net!

©️ James Langan/RoadTraveler. All Rights Reserved

Instagram @RoadTraveler

Resources:

NEXEN Tire USA

 

Posted on

2010 Tacoma & FlipPac Camper Tire Q&A

Recently I received an email from Cliff with a few tire questions for the RoadTraveler (RT) blog. Below are his questions and my answers and comments, it’s a long one…Tires, they’re what’s on the menu today 😉

Background provided by Cliff: I have a few questions I hope you wouldn’t mind answering.  First some background; I daily drive a 2010 Tacoma TRD Off Road with a FlipPac camper and OME suspension.  Living in the Eastern Sierra I spend a lot of time on 395 between Reno and Los Angeles but, also drive many miles of desert washboard roads including the Death Valley area.  I currently have stock tires, which are due for replacement.  I have decided to invest in two sets of wheels, highway and off road.

RT. Two sets of wheels (or more) are very nice, and can save thousands of miles of needless pavement wear on your off-highway tires. However, there have been times when I didn’t have the correct wheels/tires on my truck when I ventured off-pavement because either the trip wasn’t planned or I made the wrong choice. Still, I like having a set of both more and less aggressive tires to choose from, but my all-around Dick Cepek F-C II get most of the miles.

One thing to be aware of is that two different treads might need different alignment settings to track straight and true on the same vehicle…I have lots of experience with this in recent years on my Toyotas and this is a solid argument against running two sets of wheels/tires.

Unmounted Toyo M/T tires in 265/75R16E, 255/85R16E, and 285/75R16E sizes.

Q. The highway set will likely be Michelin LTX M/S2 in a P-rated stock size.  The off road tires I have yet to decide but, the short list includes, BFG KM2’s, Goodyear DuraTrac’s, or one of the Cooper off road tires. I have 7” wide wheels and would like to get into a taller narrower tire than stock.

RT. Are the stock tires on your Tacoma 265/70R16? You might consider running 265/75R16 for your replacements, though I don’t know if those Michelins are available P-rated? I assume your truck is relatively light with the FlipPac and doesn’t need more than the original P-rated tires. Though I’m not a big fan of what I consider the excessively stiff and/or short tire sidewall world we now live in (see Wheels, Tires, and Sidewalls) with your truck and intended use I would probably lean toward a load-range (LR) C tire if I could find the tread I wanted. If not, P-rated will work just as they have been.

Another question when discussing tire load ranges and ruggedness is have your OE tires been found severely lacking during the off-pavement travel you’ve already done? And even if the answer is yes, is a jump all the way to a load range E warranted, or would something more moderate like a load range C or D be more appropriate?

Reports on the Goodyear DuraTrac wear vary from excellent to very poor, and it seems the weight and/or driver of the truck has much to do with their longevity. Few complain about a lack of traction with the DuraTrac and a major positive is that Goodyear offers the LT265/75R16 size in both LR C and E, and I would suggested the LR C since you are concerned about of the ride quality penalties of an E-rated tire.

Q. My question is this.  On rough washboard roads does the difference in tire volume between the following sizes 255/85-16, 235/85-16, and 265/75-16 make any noticeable difference in ride quality?  Will one size tire provide a smoother ride over the others?

RT. The short answer is yes. Everyone’s butt dyno is calibrated differently, and truck loading, suspension, and tire PSI all make a difference. As I mentioned in the post linked above, I could clearly feel the difference between two sets of Toyo M/T ties on my 2005 Jeep Rubicon, both using the stock 16×8″ wheels, one 265/75R16E the other 285/75R16E. Both tires have 3-ply sidewalls and 7-ply treads. The only difference was the sidewall height and volume of air in the tires. I was aware of the slight but noticeable ride difference on relatively smooth local streets, and these differences were magnified once the impacts were deeper or sharper off-highway, even when aired-down.

So if you are merely analyzing the ride difference in sidewall height and/or volume, again the short answer is yes, one will provide a smoother ride than the other. But it is more complicated than that once you start changing load-ranges. All of the LT235/85R16 tires currently offered are E load range. My old favorite LT255/85R16 used to always be LR D, but now many have changed to load-range E. The LT265/75R16 size offers the most choice, with many load-range E treads, but a few LR D and C as well, just depends on the specific tire and manufacturer.

With the above in mind, it’s very difficult to say what size will offer a smoother ride based solely on the size or volume of air in the tire. Generally speaking, when running the same PSI, a LR D 255/85 will ride softer than a 235/85 or 265/75 LR E, a LR D 265/75 would ride better than a LR E 255/85, and a LR C 265/75 will beat them all. It should be noted that a LR C, 6-ply rated tire was considered a fairly heavy-duty light-truck tire a decade or two ago, and they can still be plenty depending on the rig, loading, and use. But those were the days before our super-sized world, which now includes; diesel pickups that have more torque and horsepower than commercial medium-duty trucks did, half-ton trucks with a payloads up to one ton, and 1-ton pickups that are rated for two tons or more in the single rear wheel (SRW) applications. Still, when one confirms the loads that modern light-truck (LT) tires are rated to carry, there is plenty of room to choose something less than a LR E for many applications.

Goodyear DuraTrac 265/70R17E and Dick Cepek F-C II 265/75R16E

Q. Most if not all narrow off road tires seem to be load range “E”.  Is an “E” tire too stiff for a lightweight truck like the Tacoma?

RT. That’s your call, many people think they are fine. Load Range E tires have become the norm these days, though they are not needed or necessarily desirable for every light-truck or Tacoma, and while some think they are overkill and sometimes too stiff, they are certainly popular. The stiffer the truck’s suspension the more bothersome I find stiff tires. For example, I really prefer a load range D tire on my old F350 as without a ton or more on the rear springs the ride can be very firm on-road and jarring off-highway, but the added give in a tall LR D tire when aired down makes it much more pleasant. Of course if my truck was used at its maximum gross vehicle weight rating (GVWR) most of the time, a stiffer tire would be better. But I’ve found a LR D works well both empty and loaded with appropriate air pressure, the duty-cycle matters.

Compared to your stock P-rated tires I have little doubt you will be able to feel the difference—on and off-highway—if you slap on a set of LR E treads and run the same PSI. I would suggest a LR C or D, if they’re available in the tread you want.

Q. Would a “C” load range tire provide a smoother off road ride?

RT. Yes.

Maxxis Bravo 761 & BFG KM, both 255/85, LR D with 3-ply sidewalls, a rare combination.

Q. I’m looking for a tuff, 3-ply sidewall, off road tire that will still provide a smooth ride in the rough stuff.

RT. Well that’s a tall order. The tougher the tire the rougher it will ride. The Toyo M/T I mentioned above is a very rugged tire, also a very stiff tire, particularly on a light truck. They are also expensive and typically balance very well. The new Cooper S/T MAXX is similar, very rugged but also stiff and firm riding…there is no free lunch. Remember that most LT tires still do not have 3-ply sidewalls, they have 2-ply sidewalls. Take two tires of essentially the same construction, one with the 3-ply sidewall and the other a 2-ply, the 3-ply sidewall tire will ride firmer. Preferring a more compliant ride, but sometimes needing a stout tire for heavy-hauling or puncture resistance in the rocks, I prefer a LR D with a 3-ply sidewall when I can get them, like the Dick Cepek Mud Countrys currently on my 4Runner, but that’s an uncommon configuration. Typically I just live with a regular 2-ply sidewall tire, like my current favorite, the Dick Cepek F-C II in a load-range D 285, which are currently on both my F350 and Tundra.

You should probably try to decide on the size and/or tread pattern you want first, then make the necessary concessions on load range and ply ratings, or visa-versa. You are not going to be able to have the most rugged tire, that is also very compliant on the washboard, just like the more aggressive treads generally don’t offer the wear of milder tread.

There are some other things to consider if you go taller than the 265/75R16 or 235/85R16 sizes (31.7–32″) on your Tacoma: Will your spare tire still fit in the OE location, is that important to you, and is the loss of torque and possibly fuel economy worth the switch to LT255/85R16 tires with stock gearing? Though I purchased a 4th Gen. 4Runner, I’ve often considered the 2005-up Tacoma platform, and thought that a 32-ish tall tire was very good compromise while begin able to run the correct, matching size spare without a tire swing-away.

Though in your case, the 255s would likely only be for occasionally use, and maybe the loss in acceleration and having a smaller spare would not be a deal-breaker? Since the Taco is a traditional, part-time 4WD system, there is not much concern when running a slightly smaller, 265/75 spare for short distances as long as the VSC and ATRAC don’t mind; they didn’t on my 4Runner when I ran that combination for a brief test.

Rollin’ Forward with RoadTraveler

Copyright © 2012 James Langan

Posted on

MPG, Fuel Economy, Tire Width, and Treads No. 1

Newer, detailed article, click here: Tread Matters

 

Will The Most Efficient Tires Please Drive Forward

It’s often stated that narrower, lighter, less aggressive tires are more efficient and will yield better fuel economy, but how much better? To properly compare apples and pears one must take care to reduce the variables that are always present during real-world tests. In this case I used the same vehicle, same gas pump, during similar weather conditions and time of day, calculated the odometer error, and used the same section of freeway. The GPS-confirmed road speed was 64-MPH and was maintained by cruise control. The tires were inflated to 35-PSI in all but the last test with the Dick Cepek F-C II treads where I goofed and only used 32-PSI. The F-C II tires performed so well I doubt they could have provided better economy with an extra 3-PSI.

Cooper S/T 255/85R16D on Toyota 4Runner, @ 15 PSI.

If you think the fuel economy numbers listed below are too high you are partly correct, the tests involved almost zero city driving. The variables of in-town driving are not repeatable and won’t yield consistent data. What these tests do show is the fuel economy potential of this vehicle and establishes a baseline against which other tests can be measured. For each test the modified 2006 4.7L V8 4Runner was fueled and then driven a few blocks to the same freeway onramp, onward to a specific exit, and then the route was reversed and terminated at the same gas pump where the engine was promptly turned off.

Dean SXT Mud Terrain & Cooper S/T, both 255/85R16. Two of the narrowest 255/85 tires made.

All the tires used were close to the same diameter, about 33-inches, and they were all mounted on Toyota FJ Cruiser TRD 16 x 7.5-inch aluminum wheels. Because of the slight differences I tire height, one corrected odometer reading of 56.76-miles was used for all the tests. Listed below with the figures are the weights of each tire/wheel combination.

Results:

Cooper S/T LT255/85R16D: 75-lb  3.027-gal. = 18.75 MPG

Maxxis Bighorn LT255/85R16D: 82-lb  3.017-gal. = 18.81 MPG

TreadWright Guard Dog LT285/75R16E: 87-lb  3.331-gal. = 17.04 MPG

Dick Cepek F-C II LT285/75R16D: 83-lb  3.121-gal. = 18.18 MPG

Maxxis Bighorn 255/85R16D, TreadWright Guard Dog 285/75R16E, Cooper S/T 255/85R16D

Commentary

I was a little surprised that the very narrow and light Coopers consumed more fuel than the heavier, more aggressive Maxxis Bighorns. Though when filling-up after the Cooper test the gas-pump didn’t stop normally and a little gas spit from the filler, possibly contributing to the lower reading. Longer distance tests would likely be more accurate, but this type of testing is very time consuming and expensive.

It was expected that the heavier, wider TreadWright Guard Dogs with their aggressive lug tread would use more fuel. The Cepek F-C II tires impressed me by splitting the difference and topping eighteen MPG!

Cooper S/T 255/85R16D, Dick Cepek F-C II 285/75R16D

Surely tread design, width, and weight all make a difference. My theory is that width and tread design have a larger impact on fuel economy than tire weight, at least when there is only a few pounds difference. There is five pounds separating the Maxxis Bighorn 255/85R16 and TreadWright 285/75R16, but I don’t think those additional few pounds account for the 1.77 mile-per-gallon difference. There is a seven pound difference between the Maxxis Bighorns and Cooper S/Ts, but the results for these two 255s were so close you could call it a tie.

Your mileage will vary.

Copyright © 2012 James Langan

Posted on

Traction Tire Preview Prelude

For several years I’ve been a fan of what are often called aggressive all-terrain tires. Labels and classifications can be difficult, sometimes neither descriptive nor adequate as there is much crossover, gray-area, and blurred lines with tread designs. These tires are not as open as a mud tire, but offer much more void than the typical all-terrain or all-season tire. Current examples include Mickey Thompson ATZ 4-rib, Dick Cepek F-C II, Cooper S/T Maxx, Goodyear DuraTrac, Dean SXT Mud Terrain/Cooper S/T, and the Toyo M55. These treads are also called traction or commercial traction designs.

Limited Terrain SUV Tires

When marketing types decided that utility vehicle was no longer an adequate description for 4WD utility wagons, the Sport Utility Vehicle (SUV) appeared, surged, then dominated the light-truck utility market. Lighter-duty all-terrain tires that offered less void and less traction became popular on the increasingly soft SUVs over the past two decades. It’s understandable that SUV tires became so road-biased, as invariably that’s where many log all their miles in their SUV trucks, but many of these conservative “all-terrain” treads would be more accurately described as all-season tires.

Michelin Cross Terrain SUV tire, properly labeled an all-season highway tire.

Despite the 4WD SUV becoming the modern on-highway station wagon for much of the U.S. if not most of North America, there are still those that want their 4WD wagons to be body-on-frame truck designs, shod with better, higher void traction tires. These folks include hunters, sportsmen, off-highway adventurers, people who live or work in rural areas, and those who travel in serve climates. For a variety of reasons a mud terrain tire may not be preferred (less MPG, longevity, and less traction on wet roads, with more noise) but a low void all-season tire labeled and masquerading as an all-terrain often doesn’t do the job either.

More void is desirable to absorb debris and let it escape. The wetter the material the more void you might want, and open, lug designs are typically louder, though modern tire design has reduced the noise penalty for some traction tires.

Toyo M55 & Multi-Mile TXR LT255/85R16D

What Size

I’ve never been a fan of needlessly wide tires, but wide tires have dominated the enthusiast 4×4 truck aftermarket for several years. Fat tires work well for some applications, but have many limitations for common usage, particularly on-pavement, where even the most active off-highway explorers travel thousands of miles each year. A slight correction seems to have occurred, where not every enthusiast 4×4 tire needs to be over 12-inches wide; 285 mm wide tires have caught on.

While I’m currently using and have accepted 285s, in my mind they are still a bit wide, roughly 11.5-inches depending on the tire—narrower tires track straighter and offer better MPG. Drivers are at least aware of fuel economy because of the cost of fuel, though I don’t see many people driving for fuel economy, bad habits are prevalent and it seems we’re often in a hurry.

The days of much narrower 33-inch enthusiasts tires like the LT255/85R16 are disappearing fast. Thankfully, if you don’t want such a tall tire, there are many 235–265 mm wide treads in the 31–32-inch range that can deliver better fuel economy.

Great traction tires: LT255/85R16D Cooper S/T & LT285/75R16D Dick Cepek F-C II

Eighteen Inch 33s

Not knowing much about 18-inch tires or wheels, but owning a set of take-off eighteens, I studied the options and was pleasantly surprised to discover the LT275/70R18 size. This size is just slightly narrower than the common 285 mm treads in either a 16, 17, or 18-inch, but with a reasonable aspect ratio of 70 percent. Most 275/70R18s are 33.3-inches tall, very similar to the tall 255/85R16 size that I’ve loved for fifteen years.

Eighteen-inch wheels are two inches taller overall, so tire sidewalls are a full inch shorter at the bottom (the part we feel and drive on). Historically 255/85R16s were flexible and pleasant riding load-range D designs, though load-range E is becoming more common in a 255/85, but 275/70R18s are almost all load-range E rated. Not all load-range D or E tires are created equal, some are stiffer than others, but shorter load-range E sidewalls on a 275/70R18 are going to be stiffer in almost every application. Again, stiff sidewalls can be a positive or a negative, depending on your needs and preferences, refer to this Wheels, Tires, and Sidewalls article for more on this subject.

To be continued…

Copyright © 2012 James Langan

Posted on

LT255/85R16 Tire Delivery Part 3

Long before my route was paved there were much hardier travelers who passed this way. I stopped for a brief photo and took a moment to reflect. Lately I’ve been reflecting on how thoroughly spoiled we are with easy, efficient, convenient long distance travel. Several decades ago vehicles were not as low-maintenance and relatively trouble-free as they are now. Before the transcontinental railroad, traveling across The States was a serious, life-threatening endeavor. As modern motorized backcountry travelers there is always the possibility that our machines and computers will fail and we will be reunited with primal overland travel; walking.

Beckwourth Trail

Below is a poor grab shot through windshield glare and at a substantial distance  as I drove through the small town of Quincy, California. It’s not everyday that one sees an nicely restored original Bronco with uncut rear fenders, and nice, narrow original size tires.

First Generation Classic Ford Bronco, uncut fenders and small, narrow tires.

Onward further into the country where I met Brian and his family—very kind people. Brian and I visited for over an hour, talking mostly about trucks and tires, before I started reversing my path.

After several miles I drove down a dirt road where I enjoyed lunch. I really like having a tailgate for picnics, one of the advantages of a pickup over most utility vehicles.

 

Excellent Highway Fuel Economy

After lunch and enjoying the sights and smells of the forest, my fuel economy mission resumed. Theoretically, there are many ways in which to improve fuel economy. Though if your vehicle is outfitted the way you like it and your maintenance is up-to-date, the best way to increase fuel economy is to drive slower and pay attention to your driving technique—there is more to it than simply lowering your top speed.

My not-so-speedy-delivery was a 183.7-mile all highway roundtrip, on which the 3UR-FE 5.7L aluminum Toyota V8 consumed 9.761 gallons of gasoline. The math says that’s 18.81 miles-per-gallon. Excellent.

I’d love to attain this type of economy all the time, but mixed driving, living at altitude, and driving up and down mountains makes it nearly impossible. Though for a lifted truck with a big gasoline-powered V8 engine, and reasonably large & wide 33-inch LT285/70R17D tires (Dick Cepek F-C II), being able to top 18 miles-per-gallon is an accomplishment. Some of the credit has to go to the very tall sixth gear overdrive, which lets the engine lope at very low revolutions-per-minute when lightly loaded, and use little fuel.

Road Traveler – Rollin’ Forward and Sippin’ Fuel

Copyright © 2012 James Langan