Why is it so hard to make a tire for refuse haulers?

Consider the routes. "Curbside residential pick-up" often means driving extremely short distances - in some cases moving forward less than 75 feet. This kind of high-scrub, start-stop driving reduces tread wear. Plus high brake heat is created, and because of the slow speeds, the heat can't easily dissipate.

Curbside is also where most of the debris, broken glass, nails, rocks and other road hazards end up.

When a refuse truck is full, it's time to head toward the transfer station. Depending on the location, the heavily loaded truck can drive dozens of miles on the highway at relatively high speeds. 

It's even harder for the front-loaders and long dumps that travel to debris-strewn landfills. Besides extreme off-highway service, this is some of the severest service radial tires must endure.

But R296 did rather well in this application.

Yes, very well. But Bridgestone has developed new technology to make M860 even more durable for longer tire wear in refuse service.

In what ways?

Let's start with the new ultra-durable tread compound.

It's tough enough to stand up to the high-scrub, stop-start driving that's typical for curbside pickup. The innovative tread compound also resists cuts, chips and tears, important for the trucks that must drive into a collection facility or landfill.

What else?

M860 is deeper and wider. The tread depth is 24/32" - a full 32nd deeper than the R296. With the tougher tread compound, that deeper tread promotes greater mileage.

And it's nearly an inch wider. So there's more tread volume for longer life. The wider tread design also spreads heavy loads over a wider area, distributing footprint pressure evenly for slower, more even wear.

The wider design also uses a wider casing, which creates a larger air chamber.

So it can support a heavier load?

Correct - there's more air space to support the load.

Bridgestone was the first to introduce a 10,000 lb-rated steer. Bridgestone is continuing this important feature with the new M860. It carries an "L" rating - allowing you to load steer axles to 20,000 lb (you'll need a 9.00-inch rim for loads over 8,000 lb per tire).

Is irregular wear a problem?

Typically any irregular wear is scrubbed off before it becomes a problem. Nevertheless, M860 does employ several irregular-wear-fighting features to promote longer tire life.

The first is a solid shoulder design that fights tread squirm. The design distributes weight and torque while increasing wear volume and improving mileage.

Another feature that fights squirm is the tie bars - stabilizing structures that link each tread block to its neighbors.

And while the tread pattern is computer-designed to fight irregular wear, it's also engineered to promote excellent traction.

So it can get through the mud and snow.

You have to stay on schedule, regardless of weather or road conditions. The M860 has a very aggressive tread pattern with numerous block edges and notches to bite into soft surfaces - such as mud and snow.

In what other way is M860 improved over R296?

Bridgestone has a reputation for legendary bead construction - which R296 helped create. The bead for M860 continues that tradition.

What makes it so strong?

Bridgestone's standard one steel chafer design strengthens the bead area. The M860 increases durability by adding two nylon chafers to further protect the casing, even under heavy brake heat. This is an important feature because as we discussed earlier, many refuse haulers work curbside pick up that generates considerable brake heat.

Of course, bead durability affects retreadability. Weak bead construction can damage casings, forcing you to send tires to the scrap pile.

What other features help enhance casing life?

Speaking of scrapped tires, take a look at a refuse hauler's scrap pile and you may find many tires that sustained sidewall damage. One or two sidewall scrapes may not sacrifice casing life, but three or four severe curbings could end it.

M860 adds thick, abrasion-resistant sidewall ribs to fight curbing and protect the casing.

Tread design is also engineered to enhance retreadability.

The casing-saving angled grooves discourage stones from being lodged in the tread and piercing the belt layer.

How can something on the surface
of the tread affect the casing?

By the shape of the grooves. If you look closely at the cutaway illustration, you'll see the groove walls are "U-shaped." and one side of the wall is angled more steeply than the other. This discourages stones from getting lodged in the tread and piercing the belt layer.

The center grooves add another layer of protection to fight stone drilling with dozens of stone rejector platforms.

But it's not unusual to see stones embedded in a tread groove?

No, it's not unusual. And if the stones remain there, they could push deeper into the tread groove and pierce the belt layer. That can expose them to rust, which prevents the casing from being retreaded.

How much retreadability is realistic?

Like other severe-service applications including construction and off-road, refuse haulers expect to get at least two or more retreads from each casing. That, and longer tire life, is a major objective for Bridgestone.

What kind of trucks can use the M860?

It's a good radial for all types of refuse trucks, including recycling units, side loaders, rear loaders and front loaders. It's also well suited for other severe-service applications, which require long tire life and excellent retreadability while handling ultra-heavy loads at highway speeds.

Its size, 315/80R22.5 is ideal for this kind of equipment.

One last question: What is the tire's speed rating?

The old R296 was originally rated for 55 mph. The new M860 is rated for 65 mph maximum sustained speed, which means "continuous operation at that speed for one hour or more."

This means less time on the highway between the transfer station and landfill, for more productivity.

Bridgestone built the M860 with superior bead durability to stand up to refuse haulers' considerable brake heat and extremely heavy loads. A durable bead enhances retreadability.