BFGoodrich grooveable Krawlers mounted on MRW 17" beadlocks
By Tim Downs

I’ve 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 pattern.

When I 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).

With 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 tire groover.

To the 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.

At first 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).

Here's 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 inch.

I liked 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.

This is 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.

Here's 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.

Mounted 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?

As previously 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.

This very 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.

The quality 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.

Here you can see the additional inner weld, nut certs and the 3/8 grade 8 bolts.

From my 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.

By following 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).

Final torque value being set to 15 ft-lbs. I'm now ready to get it.

I decided 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).

Here's 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 near future.

Here the MRW RockCrusher ring is saving my premium hubs from some sure damage.

Here's another angle of MRW's RockCrusher ring crushing granite boulders. The only damage that was evident was a little orange paint on the rocks.

This is 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.

MRW 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.

BFGoodrich 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.

Contact information:
BFGoodrich Tires
Consumer Relations Department
P.O. Box 19001
Greenville, SC 29602-9001
1-877-788-8899 (8:30 AM - 6:00 PM EST M-F)

Marsh Racing Wheels
2401 N. Mount Olive
Siloam Springs, AR 72761