The new Bridgestone R196 radial is specifically designed for longer wear on spread axle, tri-axle and other trailer positions where fast wear has been a problem.

How can I learn to “read” my scrap?
Bridgestone offers a video, Saving Through Scrap Tire Analysis (If you don’t have a copy, check the box on this issue’s reply card). There’s also a useful book from The Maintenance Council (TMC) of the American Trucking Associations, called the Radial Tire Conditions Analysis Guide (Call TMC at 703-838-1763).
They’ll help you learn what your scrap can teach you.

What can I expect to find out?
Mostly, which tires are working ­ and which aren’t. If a significant number of tires are scrapped for any other reason than simple wearout, there’s probably something you can do to improve future performance.

Do trailer tires wear more slowly than tires on other positions?
Some do. Some don’t. In many cases, trailer tires do have a slower rate of wear than other tires. There are several reasons for that:
     No steering. Unlike steer tires, which generally wear fastest, trailer tires don’t steer the vehicle (except when alignment is way off ­ which we’ll discuss in a future article). So, they’re not subjected to the huge forces needed to change the course of an 80,000 pound truck.
     No drive torque. Unlike drive tires, trailer tires aren’t being driven by the engine.  So slip and engine torque aren’t boosting their wear rates.
     Relatively light loads. With today’s weight restrictions, tandem drive and trailer tires are not likely to carry more than 4,250 pounds each (5,000 pounds on single axles).  That’s over 29 percent less than the 6,000 pounds often found on steers, and usually results in much slower wear.

But doesn’t slow wear increase chances for irregular wear?
Often it does. And that’s one of the reasons why many trailer tires are of the shallow rib variety, with a depth of about 12/32” or so, like the Bridgestone R194. Because wear is slow, a shallow tread still provides long tire life, and tends to produce even wear.

  If wear is fast, but even, a deeper tread may help. And if rapid wear comes from spread axles or high maneuvering scrub, a specially designed tire, like the Bridgestone R196, may improve tread life.
     Besides a 33 percent deeper tread (16/32”), the R196 has a square shoulder design to resist wear caused by side forces.

Can we also protect against sidewall damage?
Several Bridgestone radials, including the R194F (and others with the letter “F” in the model number) are available in versions with a sturdy, sidewall protector rib.
     While sidewall protector ribs won’t eliminate damage, they can help protect against some of the cuts, scuffs and abrasions that result from curbing and maneuvering on city streets, at docks, in railyards, etc.
     And, because there’s a protector rib on both sidewalls, if one rib becomes worn, you can reverse the tire on the wheel to expose the other rib for continued protection.

Could we use steer-type tires on our trailers?
Certainly. But you’ll need to do a cost per mile analysis to determine the benefits of switching to a deeper tread steer-type tire.
     Deeper treads may also produce other problems:  With severe turning side forces, a deep tread can act as a lever, increasing internal stresses ­ especially on belts ­ and may result in increased numbers of belt separations.
     At the same time, if turning side forces are high, steer radials that incorporate decoupling rib structures may suffer damage to these decoupling ribs.

What about rotating steer and drive tires back to trailers?
An excellent idea. In a previous article (Volume 2, Issue 2, page 12), we showed how one fleet reduced its cost per mile by moving ultra-deep tread M726 drive radials (30/32” original tread depth) back to trailer positions with about 8-12/32” of tread remaining.

How does trailer radial selection affect retreadability?
All Bridgestone casings ­ including those on Bridgestone trailer radials ­ are designed for retreading. So you can choose the tire that works best for you, then retread it for drive or trailer positions. With other brands, you’ll need to ask your supplier.
     Of course, some fleets run nothing but retreads on their trailers, and enjoy great success with them.

What should we use off the road?
If you work off-road ­ even if only occasionally ­ consider tires designed for on/off-highway service, especially if you’ve experienced tread “chipping” or “chunking” with on-highway type tires.Bridgestone offers several on/off-highway radials suitable for trailers, including the M857, M840, M843 and the M844F wide base radial. All incorporate special tread compounds and casing construction for off-road use.

    There are lots of options in trailer tires. Your experience and a good look at your scrap can help you decide which is best for you.
     Next time, we’ll move to the second letter of our “S.M.A.R.T.” acronym, “M,” for “Maintain your tires and vehicles.”

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