Tell us about the M825.

The biggest news about the M825 wide base drive radial is that it is deeper and wider.

How much so?

The M825 has a very deep 29/32" tread depth – which is 3/32" deeper than the Greatec Drive radial. And its tread width is 0.39" wider. So there’s more tread volume for longer life. The wider tread design also spreads weight and wear forces over a wider area. This distributes footprint pressure for slower, more even wear.

The solid shoulder design also promotes slower, more even wear, again by distributing weight and torque forces. And it does so by fighting block squirm and the irregular wear that results from it.

What about the R125?

While the new R125 wide base trailer radial replaces the former trailer tire, it shares many of the same product features, especially tread pattern and irregular-wear-fighting designs.

For example, the Equalizer Rib and Defense Groove structures [Editor’s note: See the article on how Defense Groove features work in this issue.] combat initiation and spread of irregular wear, promoting even wear for longer mileage. The notches along each rib are small, but they do a big job in absorbing rib edge stress for longer, more even wear.

Are wide base tires susceptible to irregular wear?

All tires are prone to irregular wear because uneven pressure very often initiates irregular wear. That’s one reason why it’s so very important to keep the entire tread, not just the center or shoulders, flat across the pavement. Since wide base radial tires are so wide, concentrating on the belt package really pays off.

Both the M825 and R125 use Bridgestone’s patented Waved Belt design to maintain uniform pressure, keeping the tread flat across the pavement for long, even tread wear.

How does it work?

Two steel belts are formed into a gentle “waved” pattern. This design controls casing growth and keeps the footprint properly shaped. By the way, all Greatec wide base singles use four steel belts for added durability. The other two belts use angled steel cords.

What about retreadability?

Greatec tires are built to be retreaded. For example, the T.I.P. (Turn-In Ply) design significantly reduces stress in the bead area.

It does so by wrapping the body ply around the bead bundle, removing it from harm’s way. This design improves durability.

Take a look at this drawing of the T.I.P. compared to a conventional bead design. Both illustrations show a thick white line – that’s the body ply coming down and around the bead bundle. Instead of folding back up, the T.I.P. design is a “wrap and tuck,” that loops the body ply over the bead bundle.

Another feature that increases retreadability is stone rejectors. Take a close look at the bottom of the grooves – the M825 drive radial has these tiny “buttons” in the center grooves, while the R125 has them in all its grooves.

What else?

Several things. For one, R125 trailer tires use tough sidewall ribs to fight curbing damage. They’re on both sides of the tire, so you don’t have worry about the tires being mounted the wrong way.

How do they improve durability?

The design helps reduce groove cracking that is caused by stone damage for enhanced retreadability.

Where can I go for more information?

Ask your Bridgestone Bandag representative or dealer. We’ll even mail free M825 and R125 brochures to you. Fill out a request on this Web site, by clicking on the “Brochures & Catalogs” button or call 1-888-694-0469.