grooveable Krawlers mounted on MRW 17" beadlocks
By Tim Downs
personally seen pre-molded BFGoodrich Krawler tires on anything from trail
rigs to extreme competition rigs. It seems every rig running Krawlers are
making the toughest trails and obstacles look a little easer. Last summer,
I even followed Lance Clifford running 40” Krawlers on some technical
sections at Fordyce Creek trail in CA and my old 35 Boggers didn't seem
to have as easy of a time on the same sections. With that said, how could
you improve on such a winning tire? By offering a grooveable partially molded
Krawler that will allow 4X4 enthusiasts and competitors the opportunity
to customize tread patterns. This will allow individuals to factor in specific
driving styles, terrain, and vehicle specifications when deciding on a tread
saw the ungrooved Krawlers in person they reminded me of tires that could
belong to a military vehicle or a farm tractor. The tread measures 3/4 inches
deep and is very soft. For you mechanical engineering types, I used a durometer
guide and these tires matched up to a durometer shore value of 40A (high
tech talk for very soft).
my limited experience in tire grooving, I was leery at the thought of
carving up a set of Krawlers. To help novices like myself, BFGoodrich
Tires is providing tools on their web site to assist in this process.
Here's the link
to the BFGoodrich
Krawler tire page. On the Krawler page you have two choices; the first
is a tire grooving instruction section and the second is actual tire patterns
that can be downloaded and printed. The instructions provide general guide
lines on grooving and some precautions on where and how deep to groove.
The downloadable tread patterns are actual patterns of the Krawler tread
that when trimmed and taped together form an actual size Krawler tread
section. By downloading the tread patterns and following instructions
on the link it allows you to visualize patterns prior to heating up a
left are four patterns I came up with on paper. I added notes on each pattern
indicating tread width and arrows indicating points where initial cuts had
to be made prior to final grooving.
I was tempted to just carve out my tires to an all terrain pattern that
would allow me to wheel on terrain varying from snow conditions to hot summer
days on the Rubicon trail. Then the risk taker in me wanted to come up with
a highly aggressive pattern that would provide the most traction available.
Being semi conservative, I settled on a pattern similar to a pre-molded
Krawler. I figure I can always groove more if needed (it might be a little
hard to add rubber if I groove too much).
an example of what I considered an all terrain type of tread. This tread
pattern would also allow plenty of area for future grooving. All cuts were
made using a 3/8 blade with top width set at 9/16 inch and a depth of 5/8
this pattern for an aggressive all terrain type pattern. All cuts were made
using a 3/8 blade set to a top width of 9/16 wide and 5/8 deep. The middle
groove required an initial cut prior to the final groove to achieve a square
and sharp edge.
the pattern I was initially planning on using. I liked the lack of middle
lugs which I figured would allow the middle tread to easily conform to terrain
conditions. The problem I experienced was that I could not achieve a square
final cut in the middle section (I'm sure being a novice groover had a little
to do with this). I would like to see what this pattern would do on the
trail or in competition.
the final pattern I decided to run. It's very close to a pre-molded Krawler
except for the width between main lugs. I used a 5/8 blade with a top
width of 7/8 wide for the first cut and a 3/8 blade with a top width of
½ wide to groove the lugs closest to the side wall. Lastly, I set
a 3/8 blade with a top width of 9/16 wide and cut the last set of side
wall lugs and the middle pattern tread to achieve the end result. All
depth settings were set to 5/8 inches. Click on the picture to the left
to see step by step examples.
on a set of MRW 17X8 beadlock
rims with the optional RockCrusher rings the 37X12.50–17 tires stood
36 7/8 inches tall at 12 psi. unmounted. The mounted tires and wheels combined
to tip the scale at 132.5 lbs un-grooved each (tires alone weighing in at
82lbs each). After grooving final combined weight was 131lbs. How can you
go wrong with grooving 1 ½ pounds of rubber?
stated the rim of choice for me was Marsh
Racing Wheels steel beadlock heavy duty rims. Size is a 17X8 inch, 3.5
inch backspacing with a 20 bolt bead lock ring. The set shown also includes
an optional RockCrusher ring.
impressive ring is designed to keep rocks from damaging the inner rim and
hub components. I can definitely see the advantage when faced with side
hilling a rocky section. Instead of having rocks enter the inner rim area
the large RockCrusher ring will act as a guarding plate and actually skid
along the obstacle. The ring material is made from 3/16 steel weighing in
at 11 lbs. Not much weight considering the damage avoidance gained.
of these rims is something I need to mention. From the excellent welds,
added silicone on the inner beads, and the special high-flow air valves
which speeds air entry and exit, quality is top notch.
can see the additional inner weld, nut certs and the 3/8 grade 8 bolts.
days of running non-bead locked rims, I learned the value of using bead
sealer. I applied bead sealer to the inner and outer beads even though I
did not think it was necessary.
the enclosed mounting instructions and information provided on
MRW’s website, I had each tire mounted and torqued to specifications
in less than 30 minutes (I did cheat by using an air wrench to get the rim
lock bolts close).
value being set to 15 ft-lbs. I'm now ready to get it.
to sneak a few hours at Prairie City OHV park to see what my new tire and
wheel combination would do. With the front aired down to 7 lbs and the rear
to 4 lbs traction was unbelievable. The softer compound tires combined with
beadlocks that held when running this low of air pressure preformed flawlessly.
I knew pressure was a little low but I wanted to see how the traction was
at this pressure (I used to run this pressure with my old Bogger setup).
another shot at the top of this rock. I'm sure my 30 spline Dana 44 axles
are happy about this new traction. I'm sure rear axle upgrades are in the
MRW RockCrusher ring is saving my premium hubs from some sure damage.
another angle of MRW's RockCrusher ring crushing granite boulders.
The only damage that was evident was a little orange paint on the rocks.
a great view to see how squared up the 37X12.5-17 BFGoodrich Krawlers mount
up on MRW's 17X8 rims. I'm very pleased with all aspects of both the tire
and wheels. I'll report back with more detailed information after a few
more trail runs are competed.
is offering beadlock wheels in 15, 16, 17, 18 and now 20'' patterns in a
very impressive bolt pattern selection. All sizes offer options of HD (heavy
duty w/20 bolts), ED (extreme duty w/40 bolts), and RockCrusher cover. The
extreme duty wheels are recommended for vehicles weighing over 4500 lbs
and/or vehicles that will see extreme jumping. See MRW's
web site for application and size guidelines.
Tires is currently offering two sizes of Krawlers, 35X13.50R15 and 37X12.50R17.
The 37X12.50R17 is available two versions, one is the pre-molded Krawler
pattern and the second is the partially molded grooveable Krawler. See BFGoodrich
Tires for all your BFGoodrich tire needs.
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