We've seen and used our fair share of offroad tires
ranging from light All Terrain tires up to the nasty
knarly bias ply MT Mud Terrain or Maximum Traction
as some say MT stand for. So when Mike from
Green Diamond Tire Corporation asked us to do some
honest real world offroad testing of a set of their Green Diamond
Icelander MT tires, we thought why not, another tire
we could beat the hell out of and give our honest
opinion of. So Mike personally deliverer a set
of Green Diamond Icelander MT's in size
LT31x10.50R15-C which we promptly installed on one
of our vehicles we'll call Scrappy. Scrappy,
not because it's ready for the scrap heap, but
Scrappy because it's always been ready to scrap with
some tough obstacles, mud holes and rough trails
over the years and 2 four wheeling
owners without hesitation. Put another way, this 92 Toyota has
been beaten for years and keeps coming back for
more. Scrappy is a daily driver as well as a
weekend warrior. During the week this tough
little truck runs a set of All Terrain street tires
then when it's time to play in the offroad, it gets
a set of Mud Terrain wheels slapped on it.
It's had rear a locker in the past but currently
it's rear is an open pig leaving any tire testing
dependant on the tires themselves and not traction
controls or enhancements. We ditched the All Terrains for the set of Green
Diamond Icelander MT, which fit nicely under the
fenders for the local law enforcement. We live
in PA where tires outside the fenders is grounds for
A Little Background on the Green Diamond
to our testing we had never heard of Green Diamond
Tire Company. Leading up to getting the tire
on the trail, we did a bit of reading about
the Green Diamond Tires and had an interesting
discussion with Mike from Green Diamond Tire about
this tire specifically. We found out a few
interesting facts about it which put this tire
outside the average mud terrain tire category.
Several features that make up this unique tire set it apart from the
rest of the MT tires. Manufactured in the U.S.A. by Green Diamond
Tires, the Green Diamond Icelander uses technology invented in the harsh
conditions of Iceland to enhance an otherwise great performing offroad
tire. The most notable feature of this tire is a mixture of hard silicium
carbide granules found in the tire tread. The silicium
carbide granules are found from just a millimeter below the initial new
surface veneer to the last bit of tread on the tire carcass. What
does the hard silicium carbide granules do for traction? Quite a
bit according to users of the tires. Most prominent, the carbide
granules work like silent studs on all surfaces and terrains, increasing
traction on otherwise slick surfaces such as ice, wet roads and rocks.
For this reason tires with this technology are popular in the frigid
winter conditions of Iceland. In the states, Green Diamond Tire
produces remanufactured tire with this technology in many models to
choose from in several popular sizes. The Green Diamond Icelander
MT is a Mud Terrain tire with an aggressive directional tread pattern
designed to propel the vehicle through the deep mud, over rough and
rocky terrain. With 8 or 10 protective plys (model dependant), the
Icelander performs very well in Mud with excellent self cleaning ability
using multiple channels to move the mud away from the tire to find
traction. Although it's best traction will be found in it's
forward direction, the tire also does well in the reverse direction of
it's direction tread design. Found down the center of the
Icelanders tread design is a large stepped and staggered center void
that helps to channel mud, water of whatever out through to it's voids
running laterally towards the sides of the tire. The staggered
pattern outer lugs prove quite effective in scooping and moving mud,
earth and snow,
which equals forward momentum.
The first 1000 Miles
As soon as we had the tires mounted we wanted to go thrash
them against the rocks and through the mud of a local farm to see how
the perform but time didn't allow that to happen immediately.
Instead our upcoming trip to the mountains would be the first real test
of their offroad capabilities. Up to that point Scrappy
accumulated about a thousand miles of highway and around town driving.
During this time the silicium carbide granules began to surface, which
was pretty interesting. We attempted to pluck a few granules out
and found it pretty difficult to remove them, which is a good thing
meaning they probably will stick with the rubber pretty well. We
did manage to get a few out and found them to be just a few millimeters
in size but very hard.
On the Street
During the first 1000 miles or so John, the owner of the truck, made these
observations about the handling, noise level, cornering and braking of
the freshly installed Green Diamond Icelander MT. First to be said, they
balanced well which is good for any tire but even better for a larger MT
type tire that will quickly let you know the balance is out. On
the street and highway, road
noise is minimal. A slight hum from the tires but nothing that
is annoying, and on the contrary, sounds good. Apparently the tread pattern is good for preventing
lug slap and harmonics that is commonly associated with tires geared for
offroad. Dry pavement cornering the tires feel strong and hold
traction well. Air up to their recommended pressure, they felt
strong with good stiff cornering especially for a tire with a tall
Section Height, the height of the rubber rim to ground (for more on tire
definitions and descriptions see
this page). Stopping traction is good on dry
pavement, similar to the siped all terrain that were on the truck
previous. Wet weather stopping traction required a little more
distance, mainly as we gather due to the lack of
sipes in the large
lugs, which would make it about the same as another MT type tire that
did not have sipes.
As the silicium carbide granules began to appear (just under the thin
layer of rubber veneer), wet weather traction on the paved surface
improved as the hard silicium carbide granules found in the tire tread
become exposed and compliment the tire tread compound. Since the
granulars are spread throughout the tire tread depth the hard silicium carbide granules are constantly
renewed for the life of the tire.
is where this tire's abilities shine. Shortly
after installing the Green Diamond Icelander MT
tires, we had been planning to make a trip to a
little know valley in the mountains to do some 4
wheeling over a weekend and John's truck, equipped
with the Icelander MT's, was going to be put through
some challenging paces that were to involve mud,
rocks, mountain logging trails and whatever else we
Upon arrival Scrappy's Icelander's were air down
to a modest 18 to 20 PSI, which is probably a little
high to really soak up the bumps and maximize
traction but it was adequate. We occasionally
hit the road for a short time to get food or visit a
few local places and this PSI was sort of a
compromise. Below is a summary of John's
perception and our observations of the Icelander
MT's performance in some rough mountain conditions.
The Icelander MT also provides excellent traction on rocks. When
aired down for offroad, the Icelander wraps well around rocks as the
hard silicium carbide granules found in the tire tread provide tiny
sharp edges of grip in the rock surface. This feature is
especially noticeable on wet rocks or where ice and snow may be present
and affect offroad traction.
Attacking the Mud
When we considered a few mud holes to run through,
one mud hole stood out above all the others.
This mud hole has a reputation for eating Jeeps and
getting worse over time. Located along the
banks of a small mountain stream, this mud hole
started as streamside trail that was a saturated and
weakened due to a beaver dam just downstream.
One day a Land Cruiser was passing by this spot and
the ground just opened up and swallowed the heavy
vehicle. After locking the differentials and
applying plenty of right foot, the he was out of the
hole. But that was the beginning of many
attempts to get through this hole. While the
beaver dam no longer remains, the mud hole continues
to challenge many. It has been known to break
axles, blow engines and almost flip a few vehicles.
So it was the perfect mud hole to send John's
Scrappy into to test the new Mud Tires.
The personality of this mud hole changes like the
weather. Literally. Today the creek is
low, the weather dry and it hadn't rained in a
little while so the mud of this hole is actually
worse than usual with the consistency of thick
cement and sticks to everything like plaster or
John's first attempt to get in and get dirty didn't
carry much momentum and as soon as he stuck his nose
in the mud hole, he quickly realized he'd need a bit
more speed to get into the hole. A quick yank
back out, another shot at it with some momentum and
he was moving through the trench of mud, pushing a
wave of cement ahead of him. Check out the
video to see the action.
Getting in the mud hole was the easy part.
Getting out was the challenge. John's Truck
has open differentials but thanks to the
Icelanders, he could plow through the mud without
a problem. Due to the thickness of the mud,
the tires were really put to the test with
attempting to self-clean the tread but with a
little wheel spin, they kept finding traction.
Enough traction to mount an attack on the exit
embankment, which was about a 3 to 4 foot vertical
embankment. The exit of the mud hole
required a quite steep approach angle, more
than the front of the truck but with multiple
attempt to launch up and over the embankment out
of the mud hole, he wore down the embankment
allowing him to get the front of the truck up out
of the hole.
Working the Mud
John quickly realized the key to getting out of this
mud hole was momentum to break overt the embankment.
The Icelander MT's were doing a good job if
propelling him forward as well as rearward in
multiple attempts to break over the embankment.
The big challenge getting out of the hole was
probably not traction but keeping both rear tires on
the ground. With open differentials and an
exit embankment that was higher on the right side,
John kept lifting the right rear tire off the floor
of the mud hole leading to a shower of mud at every
attempt. Because of that tire lifting and the
left tire staying planted but without power, he was
struggling to keep his momentum. Ironically if
he had another week or so, the truck would have had
a locker in the rear. Maybe next trip.
As hard as he tried, lifting that back right wheel
was killing his momentum. Even with the front
wheels trying to pull him up and out, the Icelanders
were getting him further and further with each
attempt while the lifted rear wheel was showering
the mud everywhere as we scattered to avoid getting
pelted by shrapnel.
his exit strategy
With John working his truck hard and the Icelander MT's doing a good job
keeping him moving, John was putting on a show. Ultimately Lewis
gave him a little assistance with a tug from his FJ Cruiser.
Ironically the last time Lewis was in this mud hole, he snapped an axle
trying to get out of the same hole, same embankment.
After he was back up on dry land, he spent the next 15 minutes picking
mud out of the lower grill / air intake of the ARB bumper to get some
clean air to the radiator.
Nice show for the Icelander MT's. We were impressed at the
traction in this thick mud and hope to hit it again soon, after John get
s rear locker installed.
Some of the Thickest Mud
we've seen in this valley.
Mountain Trails and the Green Diamond Icelander
With great weather complementing loads of fun, we spent the weekend trail riding on a
wide variety of trails. All along we wanted to
consciously make mental notes to get an honest evaluation of the
Icelander MT tires. Everywhere we wheeled, the Icelander MT tires
did well. Difficult rocky areas, loose hill climbs, soft mud,
water crossings on slippery rocks, all yielded a pretty good opinion of
the performance of the Icelander MT tires. After a hard weekend of
thrashing these tires across everything we could think of, the durable
compound was none the worse for wear and the tread lugs held up good to
some of our rock crawling abuse which included a night run that where it
was difficult to see what you were crawling over.
Beyond our Mountain Trip...
Around here, sand is hard to come by but the next closest thing can be
found not too far from here. Coal slag. When a coal mine is
in operation, much of the material that is mined is not really coal but
a mix of coal, shale and rocks. Much of it is very grainy, like
coarse sand. One of the 4 wheeling locations that Scrappy is
driven in is the coal slag piles in the coal regions of eastern PA.
In this coal slag, the Icelander provides decent floatation. When wheel spin
is applied, the tread design will tend to dig as it is designed for
excellent forward traction and self cleaning.
We haven't seen any snow yet as it is early in the
year but from what we hear the Icelander MT's performance
well with the snow. We look forward to testing
them on our winter trip up here and hopefully it
will be a little cooler than last year's 50 degree
Great tire. Tough, very tough. According to Mike at Green
Diamond Tire, 8 and 10 ply tough model dependant. We encountered
no damage even though we beat hard on the Icelanders. We were most
impressed by the Icelander MT's ability in mud where it found traction
even with 2 to 3 feet of cement-like mud holding the truck back.
We find ourselves at the end of a long weekend with a positive opinion
of the Green Diamond Icelander MT tires. We drive it hard and
drove it home without incident. A highly recommended Mud Terrain
Miles after several offroad trips the Icelanders are still going strong.
On-road wear we would consider to be better than average and they still
behave well on paved surfaces. Road noise is still about what it
was when they were new although we probably should rotate them.
We've put about 10 thousand mile on this set and gone through a
northeast winter with a few icy, slick drives home from work and they
did well. Not bad for a tire without sipes. The silicium
carbide granules have been visible for a while now and they seem to be
living up to the claims of added traction specifically when conditions
get slick. We're still beating on them and they're still taking
it. So we are still very happy with this tire.
Green Diamond Tires are available through distributors across the U.S.
and from green Diamond Tire themselves. Sizes are limited but the
most popular sizes for general applications are available. For
more information contact Green Diamond Tire or visit their website.
Green Diamond Tire
Elmira, New York 14902
800.428.8696 (toll free)