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4x4 Tires Busting Beads - Built-In Bead Breakers

Folded Tire
Jimmy Nylund | Writer
Posted February 1, 2006

Pick your wheel-and-tire combination with care

Rim protectors, rim guards, whatever you want call them-those seemingly innocent rubber ridges present on many late-model tire sidewalls that are supposed to keep the wheels from getting scuffed-may not be the hot ticket for trail use. Whether rim guards help or hurt apparently depends largely on their positioning relative to the rim, the design of the rim itself, as well as where and how you use the vehicle.

We found tire-and-wheel combinations where rim guards didn't seem to affect the tire's ability to hold air one bit, but also combos that lost beads with amazing ease. If you like the benefits of running lower inflation pressures on the trail, this story is for you. However, if you never drive in the dirt or air down, rim guards won't hurt anything and can indeed help protect the rims when those evil curbs attack.

A busted bead is merely an inconvenience since it's only a matter of airing the tire back up again, but it's a nuisance we can do without. After many years of running all kinds of tires at 2 to 6 psi on various wheels, we suddenly started losing beads quite frequently. A fluke, we thought, but we got bead-locked wheels just in case. As it turned out, we should've used wheels that work well together with the tires instead.

Our tires used to stay put on the rims though we usually run just 2 to 6 psi on the trails, but then we started experiencing lots of leaks with a particular tire-and-wheel combo, and even had a tire come off both beads. This was quite embarrassing since we were towards the front of the line on an organized run and held up the entire group for more than 10 minutes while reseating the tire.

Experimenting with bead sealer helped quite a bit, but the lesson we eventually learned was that Pit Bull tires and Weld's Outback wheels don't seem to play well together. After remounting the Pit Bull Rockers on another set of old aluminum wheels, we didn't manage to lose a bead-although we tried.

It sure looked as if the Weld wheels were at fault here, but that didn't explain losing the inner bead of a Pit Bull Growler on a bead-lock wheel the next day. Now the only common denominator was the Pit Bull tires. Something strange was going on here, we just didn't know what yet.

During a bull session with Soni Honegger, we might have stumbled across the answer to these "mysterious" bead losses, as he'd noticed gaps fore and aft of the tire's bulge between tire and rim on his new BFGoodrich Krawlers. That's when it clicked; it could well be those newfangled rim protectors that are causing the problem. What seems to be happening is that when the sidewall flexes at lower pressures, the rim protector serves as a pivot point in that stiff area of the sidewall, and gaps open up on either side of the low spot. In some cases, the result is instant air loss, while other times the rim protector only traps dirt between the tire and wheel, leading to slow leaks. Several phone calls later, an assortment of tire industry people and four-wheelers agreed that we might be on to something here.

We had to stop pulling on this Cepek Fun Country because the rim was about to hit the concrete. After 20 years on the cheap steel wheel, this tire was probably more likely to crack than let go of the bead. Still, there must be a bit of proper tire-and-wheel combination in there too.

Dennis Franklin of Franklin Tire & Suspension in Yuma, Arizona, pointed out that "Rim guards were originally used only on high-pressure industrial tires." Not quite the tires we use on the trails. Warren Guidry of Interco Tire said that some of Interco's ATV tires had rim protectors to keep cut soybean stalks and the like from getting between the tire and wheel. Again, a different scenario than our trail tires, but at least a low-pressure application.

We talked to as many tire manufacturer reps as we could raise on the phone. In the end, they all agreed, or at least admitted, that rim guards could indeed have a dark side, but whether they're good or bad wasn't quite that clear-cut. For example, BFGoodrich's Jeff Cummings had witnessed rim protectors save the sidewalls on two vehicles that had smacked into a large rock at high speed. Tom Lorden, a man who has had a lot to do with the trail tires we see today, even provided the DOT standards for resistance to bead unseating. Interesting reading, but unfortunately well beyond our means and time limits.

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