THE
LOW PRESSURE REVOLUTION
Staun Products' Internal BeadLock™
is creating a low tire pressure revolution, and I'll tell
you why throughout. Words alone don’t do this product
justice. Even if you don’t read on, take a look at
the pictures. They are very impressive!
If you play in the dirt long enough, you will eventually
encounter rim- , tire-, bead-related problems. Popping the
beads off the rims is relatively commonplace. While playing
and learning about sand years ago, I actually popped four
beads at one time! I was side-hilling. I lost the two outside
beads on the downhill side, and the two inside beads on
the uphill side.
Another problem is spinning the tires on the rims. That
results from too much traction and torque, and not enough
friction between tire and rim due to low tire pressure.
These annoyances are expected by the folks that regularly
play on the Black Diamonds. Up until now, they counter these
rim/tire/bead predicaments in several ways. However, Staun's
BeadLock™ may make bead-related problems a thing of
the past at any pressure.
The Black Diamond guys may (1) install conventional bead
locks or (2) sacrifice performance by running higher "low"
pressure than they really want. They may also (3) choose
to live with rim/tire spin and get the wheels rebalanced
every so often. For intermittent air "burping,"
they usually just (4) add air along the trail and get used
to reseating the beads when they completely knock 'em off.
Staun Products' pneumatic Internal BeadLocks keep the beads
in place and tightly secure the tires to the rims. This
means that you can run exactly the low pressure you want,
and as our tests proved, with no fear of popping a bead
or spinning the tire on the rim. Isn't that worthy of being
called a low pressure revolution? And not to beat it to
death, are you aware that there are very light weight competition
rock crawlers that run zero, repeat, zero PSI in their tires!
They, along with every guy who owns 16.5” wheels,
need a low pressure revolution!
Staun Internal BeadLocks provide a way to lock both the
inside and outside tire beads to the rim. No special rims
are required. Staun has sizes to fit everything from 9 inch
ATV/Quad rims to behemoth 19 inchers!
DESCRIPTION
A fully LOAD RATED inflated tire stands a 99% chance of
having none of the problems described above. Period! In
other words, when properly inflated, the tires do their
job perfectly. That is because high (street) pressure securely
locks the tire bead against the rim and eliminates air loss
and tire/rim spin. The bead/air loss thing appears to be
borne out by the roll tests I've conducted. I've side tilted
5,000 pound 4Xs, to greater than 45°, with fully inflated
tires, and never unseated a tire bead or lost any air (see
Figure 2 and insert).
Wouldn't it be perfect if we could apply high pressure right
at the tire's beads, independent of the pressure in the
balance of the tire? Staun's Internal BeadLock™ does
exactly that. It is literally a specially reinforced mini-tube
right next to the bead. By the way, I use "wheel"
to mean the tire (rubber part) mounted on the rim (metal
part).
AVAILABLE SIZES
| Part No |
Rim Size (Inches) |
| |
|
| SBLNC1279 |
Suit 12 in rim x 7-9 in wide |
| SBLNC1479 |
Suit 14 in rim x 7-9 in wide |
| SBLNC156 |
Suit 15 in rim x 5.5-6 in wide |
| SBLNC1579 |
Suit 15 in rim x 7-9 in wide |
| SBLNC 159.510 |
Suit 15 in rim x 9.5-10 in wide |
| SBLNC151112 |
Suit 15 in rim x 11-12 in wide |
| SBLNC166 |
Suit 16 in rim x 6-6.5 in wide |
| SBLNC1679 |
Suit 16 in rim x 7-9 in wide |
| SBLNC169.510 |
Suit 16 in rim x 9.5-10 in wide |
| SBLNC161112 |
Suit 16 in rim x 11-12 in wide |
| SBLNC16.579 |
Suit 16.5 in rim x 7-9 in wide |
| SBLNC16.59.510 |
Suit 16.5 in rim x 9.5-10 in wide |
| SBLNC1779 |
Suit 17 in rim x 7-9 in wide |
| SBLNC179.510 |
Suit 17 in rim x 9.5-10 in wide |
| SBLNC171112 |
Suit 17 in rim x 11-12 in wide |
| SBLNC1879 |
Suit 18 in rim x 7-9 in wide |
| SBLNC2079 |
Suit 20 in rim x 7-9 in wide |
| SBLNC209.510 |
Suit 20 in rim x 9.5-10 in wide |
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DESIGN PRINCIPLE
Very simply put, a Staun Internal BeadLock™ divides
the innards of a tubeless tire into two air chambers. The
one nearest the beads holds rubber to metal. This means
the remainder of the tire's air space can confidently be
inflated or deflated to any pressure you desire baring blowing
it, up of course.
So how does a conventional bead lock differ?
CONVENTIONAL VERSUS STAUN'S
BEAD LOCK
Conventional bead locks mechanically clamp the outside tire
bead to the rim, always, and rarely, the inside. They do
a 100% perfect job at that. Staun Internal BeadLock locks
both the inside and the outside beads to the rim. Although
it is less common to lose the inside bead, it nevertheless
happens. Proof in point: Prior to installing Staun Internal
BeadLocks, Blaine Johnson was used to regularly and undesirably
burping air out of a rear, conventionally bead locked wheel.
With the Stauns, the problem vanished.
Conventional bead locks can be difficult to balance. As
Figure 3 shows, the conventional bead lock puts all of the
weight on the outside of the wheel, only. That's typically
a ring plus 24 cap screws and washers. This could make for
balancing problems. But on the plus side, this ring protects
the vulnerable valve stems.
Staun Internal BeadLocks are light weight (about 5 pounds
for fifteen inchers) and the weight is evenly distributed
from the inside to the outside of the rim. Further, since
some of the weight is nearer the center of the rim, it minimizes
imbalance effects. There are no balancing problems with
Staun BeadLocks.
If you drive on a conventionally bead locked flat, you stand
a good chance of damaging the rim, tire or both. The Staun
BeadLock tube and case add height to the flat as if it were
not flat, and in fact, that is actually what’s happening.
A portion of the tubeless cavity still contains air at high
pressure and keeps the rim off the ground. It does not let
the rim pinch the tire at the ground (see Figure 4).
BEAD LOCK LEGALITY
Regarding the legality of conventional bead locks in California,
I contacted very helpful Public Affairs Officer Chris Johnson.
Now, understanding that the California Vehicle Code book
is very big (over 1,600 pages!), and has many changes every
year, Officer Johnson did his best, with the help of "Commercial"
officers, NITSA and DOT to answer my question:
"Are conventional bead locks against the law?"
His qualified answer is, "As best I know, no, conventional
bead locks are not illegal."
Officer Johnson and I both are interested in learning more
from you. Please call him (714, 567-6000) or me, if you
have been cited specifically for bead locks or know the
exact facts for someone who has. In defence of both of us,
rumours are unacceptable. We need the facts, ma’am,
just the facts.
Staun Internal BeadLocks are literally invisible with the
exception of the second valve stem and that also appears
to be legal. They use conventional inner tubes, so as of
this writing, neither Officer Johnson nor I see any "street
legal" problems with the Staun Internal BeadLock™
system.
BEADLOCKS SAFER
From what's been reported from down under, they may even
make controlling highway blowouts more manageable. One mate
reports that he unknowingly drove 20 km (~12 miles) at 100
kph (~ 66 mph) on unnoticed front flat. The tire was thrashed,
but the rim survived. What's really amazing to me is that
the driver was unaware of his problem until it was flagged
by a friend on the highway. That appears to make a flat
pretty controllable. The inflated BeadLock™ adds a
“pneumatic” two or three inches between the
rim and the ground, as above, thereby making it easier and
safer to pull to the side of the road or trail (Figure 4).
This should save your rims, if not the tires, too. More
experience will confirm or deny this.
HOW IT WORKS
As the BeadLock's tube (above) inflates through its own
valve stem, (shown right), it expands until it reaches the
limits of the polyester reinforcing case assembly (all shown
above, left). The hefty polyester case top keeps the tube
“down” thereby dictating a very low profile.
This in turn leaves the remainder of the tire (tire air
chamber) to be inflated to your desired pressure. This space
accommodates low pressure flex as needed.
Note the air pressure force arrows (above right). That force,
all the way around, at the beads, is countered by a force
at the rim. These two forces pinch the tire beads to the
rim, both inside and outside.
A conventional tubeless tire secures the beads to the rim
in the same way, but surprisingly enough, the Staun Internal
BeadLock™, in conjunction with the tube and case assembly,
also take advantage of the holding forces above and below
the bead, not just at the bead. The tube and case surround
the bead, top to bottom and left to right, bringing all
of these forces together to act like a strap. This provides
additional bead holding force. It is also why one tire expert
recommends that you run tubes in tubeless tires if you air
down.
Without the BeadLock™ tube, as with a conventional
tubeless tire, the lower portion of this "strap"
is missing. The top part of the strap is there by virtue
of the tire, but there is nothing beneath the bead to complete
the “strap effect.”
If you are wondering how the air gets in and out of the
tire air chamber, you’re very sharp! Without what’s
shown just above, the tube would cap shut the regular valve
stem shown. This picture shows how an air channel is created
by the air channel walls and another piece, the air channel
floor, not seen. Also be aware that the tire (bead) is not
shown for clarity
I recommend that you
seriously consider Staun Internal BeadLocks if you regularly
run the Black Diamonds or if you are not capable of reseating
a tire bead with what you carry into the backcountry.
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| Download Full Report PDF |
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| Wide Tire Bead Help |
| Problem: With very large tires, typically 36 inches in diameter and greater, the beadlock tubes may fail. This involves most Interco tires, BFG MTRs and others. The failure can range from small holes to slits 180° around the tube right at the tire-beadlock Bead intersection. The problem appears to be caused by the tire. |
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Background: We have recently discovered all tires are not created equal as international wheel specifications assume. These specify that the space behind the bead bump be 0.750 inch/19mm. Most tire beads are 0.625 inch/15.9mm wide. However, larger tires have wider beads. Some may be as wide as 1.0 inch/25.4mm wide.
Discussion: This means that standard 0.625 inch tire beads will seat completely behind the bead bump, but for wider tire beads, a portion of the sharp inside tire bead edge will be outside the bead bump area. This causes two problems: 1) It may prevent the beadlock case from moving to seat properly and 2) the sharp edge may cause tube failure. |
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Solution: The solution is to smooth out the wide, sharp tire bead edge. Further, exercise all proper beadlock installation practices, and in particular, use lots of powder. If you run out of powder, you may buy any bath, baby or talc powder from your local 99 cent store.
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