Rubber Souls

We Test BF Goodrich’s new high-performing KM3 tires.

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Words by Peter Storck

I must admit that I push my vehicles harder than most people and sometimes I pay the price. This is probably one of the reasons why I was assigned to test and review the BF Goodrich (BFG) KM3 tires. I had tried other mud-terrains (MT) but I was still getting stuck in the same old ruts no matter how hard I seem to push the limits. 

Having led the pack for almost 40 years in off-road specific tire design and production – starting with the radial BFG Mud-Terrain T/A – BFG is now on their fifth generation of mud-terrain tire with its new KM3. It’s the successor to the KM2, which was already an industry-leading and award-winning tire design. 

While a little heavier than the KM2, the KM3 is built tough as its CoreGard Max technology helps prevent sidewall splitting and puncturing thanks to increased sidewall thickness. Further, BF Goodrich’s Krawl-TEK tread compound is designed to provide better grip and traction. The lines between the lugs are what they call Mud-Phobic bars, which assist in releasing compacted mud for improved traction.

With all of these improvements, the KM3 proudly touts a five percent increase in mud traction, an eight percent increase in rock traction, with 27 percent tougher sidewalls.

Testing

I ran the LT275/70R18/E KM3 on a 2018 Colorado ZR2 Crew Cab Diesel with trimmed fenders.  Since my testing area was near or on our property, I rarely air down from factory specifications.  The ZR2 is equipped with both front and rear lockers but I only engaged the front as required.

On Paved Roads

For many, road performance is just as important as off-road since most rigs tend run more on pavement than dirt. Plus, let’s be honest, looks are important too and the KM3 does not disappoint. Even when it sat idle, the tire’s tread pattern looked ready for action.

Even though it’s an off-road-biased tire, the KM3 performed well on paved roads – dare I say I found it comparable to some all-terrains on dry roads. In fact, the KM3 felt like it has a better ride than the KM2 and seemed to be a touch quieter. 

I also found the KM3 to have less grip on wet roads and had to take certain corners a fair amount slower than I could with my last set of all terrains. On more than one wet occasion, the front tires felt like they were plowing in the corners. I think that additional sipes could provide a more confident feeling in poor weather conditions, but that could affect its off-road durability. Since it’s a street legal mud-terrain, not an all-terrain, I think that it’s acceptable to expect compromises for different driving styles.

On Gravel Roads

Due to the area where I live and the nature of my job, I estimate that about two thirds of the kilometers that I travel are on gravel roads. I would say, in general, the KM3’s performance on gravel is on par with some of the more aggressive all-terrains. Yet, it exceeds in performance on certain sections when it gets muddy.

In Mud and Dirt

If there is just one condition when you would expect the KM3 to perform the best, this would be it. The KM3 is said to have five percent more traction in the sloppy wet stuff than the KM2, which was a leader in its class. I had been running another set of mud-terrains for about six months and there were a few spots on local trails where the other MT’s struggled. In fact, there were two small hills where I was not able to get my truck up to the top when it was dry, and another hill where it was tough to get up when it was wet. 

I don’t go really go mudding as my truck serves a dual-purpose for both play and work and it’s built more like an overland rig. That being said, I do attempt some of the holes that I probably shouldn’t. The limitation with testing the KM3 in mud for me was the fact that my truck is only able to fit 33” tires. Plus, it would get high-centered at times since other guys run these holes with 37” tires or larger. Any of the mud holes that I did get into, I was able to drive back out.  Some required a little extra effort, but I made it through.

One of these obstacles was a very short but steep 33-degree climb on loose dirt and the next one was also a very short hill but with only a 20-degree slope. Plus, it had sand under a very thin layer of brush. The third was a twisty gradual hill climb that turns into a sloppy, slippery, and muddy mess when wet. Having what I thought were a good set of MT’s before, I hoped the KM3 was going to perform better. I didn’t really expect it to, but I was wrong. 

With both lockers engaged and a little speed, the ZR2 climbed up both of the small hills with little effort. The day I tested them on the gradual twisty and muddy hill, it had been raining just before and it was sloppy. I engaged the rear locker only, kept my speed at approximately 10 to 12 kmh (6 to 7 mph) and steadily made it to the top. 

Of the three scenarios, the one that impressed me the most was the 33-degree dirt slope. This was a hill that I had been trying to conquer for more than a year with two different tires before I tried it with the KM3. Even after airing down the previous two tires, I was unable to make the climb after many attempts. The KM3 made it up on the second attempt with the front locker engaged. One thing I experienced was the bead along the rim seemed to have trouble keeping rocks from getting lodged in when aired down. I think an addition of a rim protector-style bead like the BFG AT KO2 could be a benefit for keeping rocks out.

On Rocks

My truck is not properly setup as a rock crawler, but I do occasionally enjoy some light technical rocky terrain. I decided to run down to a local river bank where there is a mix of rock in various shapes, sizes, and textures (smooth, coarse, and mixed with gravel).  The KM3 felt very sure footed over the terrain. Though there were moments when I worried I may slip on a smooth rock or sustain damage on a jagged little peak, they proved to handle the challenge with ease. I was very impressed with how much better the KM3 handled loose gravel on a mix of inclines. 

On one run, a friend of mine came along who has owned a range of vehicles – from domestic trucks to Land Rovers and Unimogs. Coming up to a short, steep, loose gravel hill after a shallow water crossing he asked me, “you’re not going to make it out that way are you?” I replied, “why not, it’s just a little hill.” He answered, “Yes, but with that sand and gravel you’re going to get us stuck with the back of the truck in the creek.”

I would only try that sort of thing in a Unimog, but I told him that we won’t know until we try. Low and behold, with only the rear locker engaged, the truck crawled up and out with no effort.  I once again attribute this to the aggressive tread and sidewall pattern on the KM3.

Conclusion

Aside from the BFG MT T/A KM3 having one of the longest abbreviations of any tire that I have seen, it offers a great advancement in off road tire technology. BFG really did take the class-leading KM2 mud-terrain and make it even better with the release of the KM3.