Axial Adventure BFG KM3 2.9" Mud Terrain Tire
Axial SCX-6 Rubicon with BFG KM3's. Photo credit: Axial Adventures / Horizon Hobbies
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When Axial Adventure first released the SCX-6 Jeep Rubicon, I was pleased to see a set of BF Goodrich KM3 Mud Terrain tires as part of the package.
Some time ago, the 1:1 Jeep Rubicon came equipped from the factory with KM3’s, appealing to serious off-road adventurers and mall-crawlers alike. Admittedly so, when I see a set of Mud Terrain KM3’s on a local 1:1 truck, it catches my eye. While not nearly as popular with the mall-crawling crowd as the Nitto Trail Grapplers or Toyo Open Country MT’s, the KM3’s show up from time to time and their selection is deliberate. KM3’s are quite expensive, retailing at nearly twice the cost of most light-truck off-road tires. |
Offsetting that price-point is the KM3’s reputation in the off-road racing community. Their ubiquity amongst championship winning trucks and buggies across the desert racing spectrum has its reasons. Specifically, BF Goodrich has more off-road racing trophies in their display cabinet than any other off-road tire manufacturer in history, and the KM3’s are a big part of that story. KM3's are not just good tires; they are great tires.
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KM3 Details
If there is a more “scale” tire in the RC world for the 1/6th market, we’re not aware of it at the time of this writing. Axial absolutely nailed the scale details of the KM3 to such a level that you need to look close at the fine print molded into the sidewalls to see that it’s a 1/6th scale tire and not the real thing. Looking over the construction details, the KM3’s are perfectly molded with well-formed beads, highly detailed tread pattern, and a non-directional tread with molded lettering on the side walls. With this tread pattern, you can’t mount these tires backwards or reversed on the wheel. |
Out on the trail with the KM3's on our SCX-6 Honcho.
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It keeps things simple accurate in scale details and you can properly rotate your tires if you happen to have an aggressive overdrive on the front axle. The tire’s carcass is thick but pliable, making it well suited for both rock crawling and trail driving.
The KM3's need to be tough enough to handle the harsh desert terrain.
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Forced Compromise – Rubber Compound
If there is one area where Axial had to compromise, it was the rubber compound selected for these tires. The SCX-6 is a heavy beast with a two-speed transmission and option to run a large pinion gear for additional speed. Axial needed to select a rubber compound which would be soft enough to grip the rocks encountered on the trail yet tough enough to hold up to some abuse for those who dabble in a bit of high-speed bashing with their SCX-6. With a KM3 tire in hand, it feels that Axial selected a rubber compound somewhere between a bashing tire and a crawling tire. It feels tough and a bit harder than a crawling-specific tire, but not plastic hard like some of the low-quality knockoff tires. Nor do they have the gritty or grainy feel of “soft” cheap rubber. |
I did a bit of digging around on the Axial website, and there is virtually no supporting info on the tire’s description page other than “High traction and excellent grip.” That’s about as “phoned in” as it gets for a generic description.
Tire Sourcing and Setup
Usually, we start our reviews with a new set of tires, but in this case, we already had a set of KM3’s on the rack in pretty good shape. They had been mounted on a custom set of aluminum beadlock wheels and stuffed with Pro-Line Racing two-stage foams. We had driven this setup a few times at Badrock Ridge on a different stock SCX-6 Rubicon, mostly sticking to lower trails and basic desert terrain. On the few steeper sections of rock, I remember at the time being impressed with their performance.
Even though the KM3’s tires were still in excellent shape, our desire was to start with a new set of KM3’s, paint the lettering on the sides of the tires in white, and hit the trail with a fresh set of white-lettered KM3’s. If nothing else, the photos would have been fantastic, and we’d be starting with new tires.
Unfortunately, our limited dealings with Axial didn’t bear any fruit, so we checked the pricing of a few on-line outfits. Shopping around, on average a new set of KM3’s was about $110 for all 4 tires, and at that price we opted to just stay with the pair we had on hand. A new set of KM3’s wasn’t in the 2024 budget, so the decision was made to move forward with the KM3’s we had on hand and save the funds for the next set of 2.9” tires.
After verifying that the tires were properly vented with three 3mm holes, we bolted up the KM3’s and charged batteries for our first day of testing at Badrock Ridge.
Usually, we start our reviews with a new set of tires, but in this case, we already had a set of KM3’s on the rack in pretty good shape. They had been mounted on a custom set of aluminum beadlock wheels and stuffed with Pro-Line Racing two-stage foams. We had driven this setup a few times at Badrock Ridge on a different stock SCX-6 Rubicon, mostly sticking to lower trails and basic desert terrain. On the few steeper sections of rock, I remember at the time being impressed with their performance.
Even though the KM3’s tires were still in excellent shape, our desire was to start with a new set of KM3’s, paint the lettering on the sides of the tires in white, and hit the trail with a fresh set of white-lettered KM3’s. If nothing else, the photos would have been fantastic, and we’d be starting with new tires.
Unfortunately, our limited dealings with Axial didn’t bear any fruit, so we checked the pricing of a few on-line outfits. Shopping around, on average a new set of KM3’s was about $110 for all 4 tires, and at that price we opted to just stay with the pair we had on hand. A new set of KM3’s wasn’t in the 2024 budget, so the decision was made to move forward with the KM3’s we had on hand and save the funds for the next set of 2.9” tires.
After verifying that the tires were properly vented with three 3mm holes, we bolted up the KM3’s and charged batteries for our first day of testing at Badrock Ridge.
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Badrock Ridge
As most of you know by now, Badrock Ridge is our main crawling area for testing out trucks, tires, foams, etc., and we’ve spent well over 100 hours with the SCX-6 in that desert terrain. Our plan for Badrock was to test out the KM3’s on a variety of rock types, such as slick rock, steep technical rock, and a little bit of casual trailing. To kick things off, we opted not to crawl up a rocky trail, but to drop down a steep rocky trail. Often overlooked in crawler performance is the truck’s ability to maintain traction on steep descents. |
Out and about at Badrock Ridge.
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Interestingly, I’ve seen quite a few trucks handle ascents and side-hill terrain quite well, but many of the “Power Wagon” builds struggle on steep, technical descents. Most of their weight is pushed forward, giving the Power Wagon builds a bulldog look. The moment the trail drops down steep, the rear axles unload and flip over the top, bouncing the truck down the remainder of the trail while shedding its scale accessories like rats jumping from a sinking ship. Looks like a yard sale of plastic truck parts when it’s over.
With the layout of our Honcho, we’ve achieved a 59/41 weight distribution with a relatively low CG, resulting in a highly stable and controlled feel on any of the trails at Badrock Ridge.
With the layout of our Honcho, we’ve achieved a 59/41 weight distribution with a relatively low CG, resulting in a highly stable and controlled feel on any of the trails at Badrock Ridge.
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Dropping into the first descent, I wanted to see just how well the KM3’s would keep things under control. I’ve run down this section of trail in the past. It’s steep, off-camber, and features a funky transition half-way down to the bottom.
To make it safely to the bottom, you need to have traction and a good eye to keep at least three tires in contact with the rock. Plan on floating the 4th tire for a good amount distance before reaching the bottom. |
We ended up filming this part because not only does it give you a much better understanding of how the KM3’s performed, but it also shows the Honcho's ability to handle the weight transition. In the video, there are three things to make note of:
1. The weight distribution of the Honcho prevented it from flipping over onto its roof during the descent. It’s amazing what four weight scales and a calculator can do for you on truck setup, and no, and out-of-the-box Honcho can’t do this line.
2. The suspension is set up for slow progression through its range of motion, resulting in a controlled movement as the shocks load and unload. For those with a very keen eye, you'll notice that we have internal springs in the shocks. The CG of the Honcho also plays into this equation.
3. The KM3’s slide, but they don’t break loose suddenly. Even as they start to lose the battle for traction, they maintain a high-level of control. The truck slides but doesn’t break completely free. The tire’s carcass and foam setup play a big role here in that it prevents the tire lugs from rolling back and folding down into the wheel. The KM3’s carcass is thick enough to support the tread pattern, but flexible enough to allow the tire to conform to the rocks for traction. Excellent design and rubber choice on display here.
1. The weight distribution of the Honcho prevented it from flipping over onto its roof during the descent. It’s amazing what four weight scales and a calculator can do for you on truck setup, and no, and out-of-the-box Honcho can’t do this line.
2. The suspension is set up for slow progression through its range of motion, resulting in a controlled movement as the shocks load and unload. For those with a very keen eye, you'll notice that we have internal springs in the shocks. The CG of the Honcho also plays into this equation.
3. The KM3’s slide, but they don’t break loose suddenly. Even as they start to lose the battle for traction, they maintain a high-level of control. The truck slides but doesn’t break completely free. The tire’s carcass and foam setup play a big role here in that it prevents the tire lugs from rolling back and folding down into the wheel. The KM3’s carcass is thick enough to support the tread pattern, but flexible enough to allow the tire to conform to the rocks for traction. Excellent design and rubber choice on display here.
Slick Rock
If there was an anticipated deficiency with the KM3’s design, it was mostly likely going to be a presumed struggle on the slick sandstone blocks comprising various sections of trail. The KM3’s rubber compound is not as soft and sticky as other crawler tires, but the tread pattern is well suited to the task of rock crawling.
On the far north side of Badrock Ridge, there’s a trail wrapping around the lower terrain, sweeping up to the east as it ascends a steep and slick sandstone slab. Early in the morning, the trail is still tucked away in the shadows, but it doesn’t take long for the sun to start warming up the surrounding rock.
If there was an anticipated deficiency with the KM3’s design, it was mostly likely going to be a presumed struggle on the slick sandstone blocks comprising various sections of trail. The KM3’s rubber compound is not as soft and sticky as other crawler tires, but the tread pattern is well suited to the task of rock crawling.
On the far north side of Badrock Ridge, there’s a trail wrapping around the lower terrain, sweeping up to the east as it ascends a steep and slick sandstone slab. Early in the morning, the trail is still tucked away in the shadows, but it doesn’t take long for the sun to start warming up the surrounding rock.
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Starting from the fine red sand at the bottom of the trail, I nosed the Honcho up to the rock until the rear tires made contact. This is always the easy part, but now it was time to do our Spider-Man impression and start working our way up the wall.
I was curious as to if the KM3’s would be able to stick to this difficult surface, but to my surprise, they hooked up rather well. The slick rock extends for about 6’ before leveling off, so we opted to make a number of loops on this slab and film the results. |
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In this take, we crawl up the slab about halfway and then stop in order to highlight a few things:
First is how strong the drag brake is on the 3 Brothers Racing Blackjacket outrunner motor; the wheels don’t move one bit. The Honcho tips the scales north of 11,000 grams, yet the Blackjacket had no trouble locking the wheels in place. Of course, the transmission’s gearing plays a favorable role in this aspect, but the fact that a motor both smaller and lighter than the OEM unit yet delivers a brag brake capable of handing the Honcho's considerable weight was impressive.
Second is the surprisingly good traction of the KM3’s. While they are a tough, do-everything in the desert rubber compound, they do have the ability to scale slick, steep rock. I hadn’t expected the Honcho to perform this well on the rock’s surface, and in fact we didn't think it would have been able to crawl up this slab at all. At a full stop, you can also see the Honcho just starting to slip back down the rock. This is where a stickier rubber compound would be beneficial.
After a few moments, we gently ramped up the throttle, showing the smooth and controlled startup of the Blackjacket motor. This sensored outrunner motor perfectly suited for this kind of crawling. We hit a few more sections of slick sandstone on the trail, and the KM3’s continued their respectable performance on this rock type.
First is how strong the drag brake is on the 3 Brothers Racing Blackjacket outrunner motor; the wheels don’t move one bit. The Honcho tips the scales north of 11,000 grams, yet the Blackjacket had no trouble locking the wheels in place. Of course, the transmission’s gearing plays a favorable role in this aspect, but the fact that a motor both smaller and lighter than the OEM unit yet delivers a brag brake capable of handing the Honcho's considerable weight was impressive.
Second is the surprisingly good traction of the KM3’s. While they are a tough, do-everything in the desert rubber compound, they do have the ability to scale slick, steep rock. I hadn’t expected the Honcho to perform this well on the rock’s surface, and in fact we didn't think it would have been able to crawl up this slab at all. At a full stop, you can also see the Honcho just starting to slip back down the rock. This is where a stickier rubber compound would be beneficial.
After a few moments, we gently ramped up the throttle, showing the smooth and controlled startup of the Blackjacket motor. This sensored outrunner motor perfectly suited for this kind of crawling. We hit a few more sections of slick sandstone on the trail, and the KM3’s continued their respectable performance on this rock type.
SCX-6 Honcho headed up another difficult trail.
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Technical Rock
Working our way across the terrain, we turned off to the right and headed up a heavily weathered block of sandstone. This unusual pattern on the rock is due to wind and water erosion, resulting in a series of slick undercuts which have a nasty habit of hooking rear tires. At one spot on the trail, there is a series of undercuts which are unfortunately spaced at nearly the same distance as the centerline of the SCX-6's axles. If you try to hit these undercuts straight-on, the tires will butt up against the undercut and just spin in place. There's no way to get traction. To beat this, you must attack the line at extreme angles, stepping one tire up at a time. It's easier said than done, and of course we got caught a few times in this section. |
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Sometimes you can slowly spin the tires when stuck in an undercut, and something will grab.
The problem with this is that the sandstone will live up to its name, slowly sanding away the tread of the tire as you attempt to hook up traction. We set up the camera to show the sanding effect of this rock as the Honcho tries to work its way to the top of the trail. If you look closely at the video, you can see small bits of rubber peeling away from the tire. |
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With purpose-built crawling tires of a stickier compound, they will grab better in this terrain, but the harder rubber compound of the KM3’s makes this trail just a bit more difficult. After a bit of working the steering to the left and right, I was able to get the Honcho out of this jam and on the way to the top of the trail. We did leave a small trace of rubber bits behind for our efforts.
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We spent the next few weekends exploring the trail system at Badrock, enjoying the warm weather, and monitoring the KM3’s performance.
Other than a few tricky spots on the slick sandstone, the KM3’s continued to impress us with their traction, toughness, and overall ability to perform on any terrain. I don’t think one could overstate just how versatile of a tire the KM3’s were proving to be. |
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Leclerc Rock Formation
Kicking off the final round of testing, we headed over to our newest crawling location, Leclerc Rock Formation, excited to see how the Honcho handles this brutal terrain. Recently we added a new section on the website about the Leclerc Rock Formation, so follow this short link here if you want to learn more the details about the type of rock and some of the associated geology info. Leclerc Rock Formation Link |
Leclerc Rock Formation
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Starting from the base of the main formation, the Honcho easily made its way up the steep incline. The traction was superb on this rock with minimal slipping.
Unlike sandstone, this eroded limestone formation provides far better traction due to its hard and sharp edges, but it comes at the cost of tire life. It’s almost like crawling up a wood rasp, and taxes the rubber tire heavily. |
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After scaling the first incline, we followed a trail running to the east side, weaving between some rock fall debris and desert shrubs.
Cruising along the trail, we passed through a small cactus garden and found a new “possible” trail to the top via a narrow spine of rock. Filming was tricky in that the far-right side was little more than a sheer drop down a 20’ rock wall, leaving the left side for us to stand and film among the cacti. Due to the length tricky setup of the camera’s location, I opted to film the first bit of the crawl, relocate the camera and tripod a few feet to the right and film the second section. Later on I spliced the two clips into one video. |
Gotta steer clear of these little buggers.
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For the crawl itself, I was forced to creep along this line a bit more cautiously in that the rock is fairly narrow and there was no way I would be able to catch the Honcho if it slid off to the right.
Slow and steady was the pace, and between the coarse surface texture of the limestone and the KM3’s high-level of performance, the Honcho walked up this with surprising ease. By this point, my confidence was growing in the tire and foam setup for this truck. It seemed that there was little the Honcho couldn't handle on this terrain. |
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Once up the trail, we worked our way through a small flat strewn with rockfall, doing our best to not get the bumpers hung up on the corners.
This isn’t the kind of rock you can slide past; it grabs you tight like a wall of hooks. It's in terrain like this that make you want a bit more steering angle. I've always found the SCX-6 a bit limited as how tight it can steer. This route fed us into a larger open area of the formation, stuffed with desert plants and a few smaller blocks of limestone which had fractured and fallen away from the main formation. |
Our SCX-6 Honcho navigating through a bit of rockfall.
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Between these blocks were several tight trails weaving their way to the top, with one of these catching our eye.
This trail was steep and extremely rough in terms of rock texture, really presenting a challenge for the Honcho. There wasn’t much room to maneuver and plenty of little rock spines waiting to grab an axle. Portal axles would be a big help on this terrain. |
To best show the Honcho’s performance, we set the camera up at the top and filmed looking down. Much like the earlier sections of trail, the rock’s rough texture made crawling up these difficulty lines much easier. Having enough traction on the rock was proving to be a non-issue, with the Honcho easily making its way to the top of this small climb.
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We closed out the day with a few more hours on the rock, searching out new trails and paths to the top.
During that time the Honcho continued to shine, with the KM3’s holding up quite well to the brutal surface of the limestone. I had expected to see much more wear and damage to the tread pattern, but other than a bit of chunking and feathering at the edges, the KM3’s seemed to be holding up. Once the last battery was spent, we packed it up and headed back to the shop. The terrain at Leclerc was fantastic, and we’re looking forward to our next crawling session. There’s a good amount of rock waiting to be explored, and it seems that the KM3’s are perfectly suited to that task. Without question, I know they will stand up to the abuse. |
Other than a bit of wear on the edges, these KM3's are having no problems with the limestone rock.
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An afternoon crawl as the sun sets.
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Conclusion
The Axial BFG KM3’s are excellent tires, handling the worst of our desert terrain and coming out on top. Their solid performance is nicely paired with an outstanding scale look, bringing a level of realism to the Honcho like no other tire. The KM3 is rightfully the OEM tire of choice for Axial’s Jeep Rubicon, capturing the essence of an exceptionally well-rounded trail and rock-crawling tire. The historical pedigree of the KM3 was well represented out on the trail during our testing, with this tire showing an uncanny ability to grind through the chunkiest of scree and rockfall as well as hauling our Honcho to the top of some steep, technical lines. |
It would be interesting to experiment with a new set of these tires and a bit of sanding / trimming of the lug pattern, as well as testing with softer and smaller foams. I’m suspicious there is some untapped potential yet to be seen.
The KM3’s are truly a “do everything well in the desert” kind of tire and not a specialist design, and that’s exactly what the engineers at BFG intended them to be. From what I have observed, Axial has carefully replicated the true essence of the KM3, delivering an excellent tire for the SCX-6 product line.
The KM3’s are truly a “do everything well in the desert” kind of tire and not a specialist design, and that’s exactly what the engineers at BFG intended them to be. From what I have observed, Axial has carefully replicated the true essence of the KM3, delivering an excellent tire for the SCX-6 product line.
Axial BFG KM3 Evaluation Results
Technical Rock: 27/30
Large Slab ( Slick Rock ): 17/20
Tire Construction Quality and Appearance: 20/20
Rubber Compound: 17/20
Tread Life: 5/5
Versatility: 5/5
Total Score: 91/100
Technical Rock: 27/30
- The KM3’s really shine on technical rock. The tread pattern is well designed, and the tire’s construction lends itself to a solid level of performance. At times the harder rubber compound made it difficult to hook a tire on tall, rounded rock edges, but with a bit of patience they were able to climb the same difficult trails we had conquered with other crawling-specific tires.
Large Slab ( Slick Rock ): 17/20
- As anticipated, the harder rubber compound hindered the Honcho on steep ascents. When compared to a stickier tire like the JConcepts Landmines, they do give up some performance. That said, they were still able to get the Honcho to the top of a few challenging slick-rock climbs.
Tire Construction Quality and Appearance: 20/20
- When it comes to fit and finish, as well as the scale details, the Axial KM3’s are superb. The molding is precise, the rubber quality is excellent, and carcass thickness is spot-on in relation to the lug height. These are surprisingly good tires for an OEM product in today's market.
Rubber Compound: 17/20
- Sorting out which rubber compound is used for these tires remains a question. Axial doesn’t make this easy with their limited details about their crawler tires, and “High traction and excellent grip” doesn’t tell us much. Compared to a few Axial tires in our collection, this rubber feels a bit harder than their R-35 compound. It’s a tough, highly durable rubber type, but doesn’t feel gritty or of low quality. I wouldn’t call it sticky, but it’s soft and pliable. For the SCX-6, I think they hit the mark with this rubber compound, and it proved to be well balanced for its intended use.
Tread Life: 5/5
- We did our best to beat these tires down, attacking steep rock formations as well as spending a long day on the highly abrasive rock surfaces of Leclerc Formation. Other than a bit of fraying at the lug’s edges, the KM3’s show only minor wear. Our guess is that it would take something close to a full year of rock crawling in this terrain to wear out a set of the KM3’s.
Versatility: 5/5
- Outside of exceptionally steep, slick blocks of sandstone, the KM3’s were evenly matched to the crawling ability of the Honcho. They handed the rough rock of Leclerc with little wear and happily crunched through chunky bits of trail at Badrock Ridge. This is an excellent do-everything SCX-6 tire.
Total Score: 91/100
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Specs
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KM3's bring a fantastic scale realism to the SCX-6 Honcho.
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