I didn’t get an H3 just to watch it look pretty in my garage. I love wheeling. That’s why one of the first things I did when I got the old girl was go hunting for a new set of tires.  I didn’t want to be an uninformed buyer so I logged onto Off-Road.com’s Hummer forum and asked what sort of tires to get. After careful research and deliberation I ended up taking the advice of my fellow H3 enthusiasts and ended up with a set of BF Goodrich All Terrain KO’s sized 315/75R16. The dirt bound members of the Off-Road nation all had nothing but accolades for the KO, but here in New England we only have dirt for a few months out of the year. For the most part, we’ve got mud, which just happens to be the BFG’s biggest weakness. Apparently “All Terrain” needed to be amended with “except for mud”.

I made a classic mistake. I asked for advice and I got it. What I failed to do was get advice from people who wheel in my part of the world and in my terrain. After putting my new tires through a few weekends worth of slippery slopes I came up with Rob’s two rules for getting tire advice:

1. Make sure that the tire you choose works in the terrain you intend to use it in.
2. If you need advice, be sure to get it from locals, not the well intentioned guy from across the continent/internet.  

My personal accounting department, also known as my beautiful wife, knew how unhappy I was with my current tires and gave me the go-ahead to get another set. Originally, I had wanted to go with something like the Interco TSL or IROK. Unfortunately, since Interco doesn’t make a size to fit my truck which, unlike these tires, is intended to be a daily driver anyway, I was forced to broaden my search a bit.

I was hearing great reviews from local FJ Cruiser owners using a new tire from Hankook called the DynaPro MT RT03. Since these guys had nothing but good, relavent, reports I decided to grab a set for myself. I went with the same size as my BFG’s, 315/75R16. This is a 35” tire and is the largest tire you can reasonably fit onto an H3 without modifications to the body or drive train.

For reference, the Base and Lux H3 come equipped with tires sized 265/75R16. This equates to a 32” tire. H3’s equipped with the Adventure package come with an upgraded tire, the Bridgestone Dueler AT, sized 285/75R16. This equates to a 33” tire.

You can determine the additional clearance you’ll get from a larger tire by dividing the difference of the diameters of the new tire and stock tire (respectively) by two, or by simply subtracting the difference in radius instead. For example, the difference in diameter between the base/lux and the adventure package tires is one inch and results in ½” greater ground clearance for the Adventure package equipped H3.

This half inch is great and all that, but anyone who has taken their H3 thropugh rough terrain knows that you can always use more ground clearance. By going with a 315/75R16 you have increased the diameter over the base tire by three inches. This gives you an additional 1-1/2 inches of well needed clearance over the base tires and one inch over the Adventure tires. Hey! Every little bit counts!

I ordered my tires. Eventually, delivery day came. The UPS man was very happy to get the Hankook DynaPro MT RT03’s out of his truck. Tires of this size are very substantial to non-wheelers; and at 72 pounds each they are not the lightest things in the world. To us they’re just cool!

My initial impressions were that the reports were right. This is an impressive tire. Its sidewalls are very thick and the sidebiters are prominent on the sidewall, promising good extra grip and protection. The lugs are not siped but the outer lugs are prepped for studs (if your state allows them for winter driving). Studs are not allowed in Massachusetts so I won’t be testing this feature of the tire. The edge of the tire immediately above the bead is ridged so that it will get better bite on a beadlock wheel.

I already had a spare set of OEM H3 wheels and seeing as the accounting department was in a generous mood (did I mention that I have a really beautiful, wonderful wife?) I decided to get a set of Staun Internal Beadlocks to keep the RT03’s firmly on the wheels at the low tire pressures I plan on running.

Mounting the tires with the Staun Internal Beadlocks was a bit of a challenge due to the nature of the Stauns, but the tires themselves did not add to the difficulty at all. What really impressed me was that once the tires were mounted and I took them to be balanced, the worst of the five wheel/tire/beadlock combinations required only 6.25 ounces to balance. The best required only 1.25 ounces and all were perfectly balanced in two spins or less. As each wheel/tire/beadlock weighs in at over 100 lbs. this is pretty impressive and says a lot about the quality manufacturing that goes into this tire.

Hummer X Club’s national event X Rocks 2007 gave me the opportunity to drive from Massachusetts to Ouray, CO, on to Moab, UT, and finally back to Massachusetts at the end of June. A distance of roughly 5000 miles covered over two weeks of driving. Not only did I get to wheel the trails I had been dreaming about, it gave me a unique opportunity to evaluate the effects of mileage on the new rubber in a short amount of time.

So far I can safely say that I remain impressed. On the road the RT03’s are very smooth and they handle predictably. To date, I have not noticed any vibration from the tire lugs at slow speed and while not the quietest tire out there, they are not all that noisy. To put it in perspective, you can talk on your cell phone at 80mph with the windows up and still hear who you’re talking to.

Before leaving to go out west I joined with a Hummer X Club member and did some quick off road testing. As is typical of New England, it was wet, slippery and all out fun. Where my BFG’s would be spinning slicks, my new Hankooks cleared out what mud we could find, and gripped the wet rocks like a starved rottweiler on a tough steak.

When I got out west to Ouray and Moab I found that the RT03’s did well just about everywhere. They hooked up without an issue in the loose rocks of  Colorado’s San Juan mountains. Even on the slickrock at Moab they worked everywhere without falter.

Aired down to 14psi the tires had well over 80% of their fully inflated height and conformed well to the changing rock surfaces. At these lower air pressures the sidebiters fold down to become an extension of the tread, greatly increasing the surface area of the tire.  Even aired down to 9psi the RT03’s stand at roughly 75% of their fully inflated height, and the grip offered is impressive. That grip allowed me to do something that, as far as I know of, is unprecedented for an H3 at Moab.

In on the Golden Spike trail in Moab there is an obstacle called the Golden Stairs. In and of themselves, the Golden Stairs are no big deal. But to an H3 the Golden Stairs are a VERY big deal. You see, the H3’s wheelbase is exactly the same as the distance between steps. When you climb the first step with your front wheels and approach the second step, your rear wheels will come to the first step at the exact same moment as the front wheels come to the second. This combination has been deadly to the H3. Front differentials, rear differentials, transfer cases, and steering racks have all been destroyed in H3’s attempting to climb the Golden Stairs.

I came to the Golden Stairs expecting to get strapped or winched up. After all, I had 2500 miles to drive home just days later. I had no intention of breaking my truck. I told myself I would give it two tries, and if I couldn’t make it, I couldn’t make it.

To help my chances of success I aired down to 9psi. With my new beadlocks in place I could have gone lower, but didn’t. I approached the Golden Stairs, the front wheels went up, I rolled forward and came to the second step… and just went right up. No worries at all. I was amazed (and pretty happy!). I attribute that successful climb to the Hankook DynaPro MT RT03/Staun Internal Beadlock combo.

While the RT03/Staun combo did allow me to climb the Golden Stairs, they do seem to have a weakness, and that is they seem to lack grip on the smoothest of rock. This isn’t saying that they are slippery. They’re not. The tires just didn’t have the raw tenacious grip that some other tires on H3’s did on the smoothest rocks. Its possible this due to the tires not being siped, however, unless you are going to be driving on slickrock every weekend, I don’t see this as a major shortcoming. I was still able to successfully complete every obstacle I tried except for one. I wasn’t disappointed, however, as another H3 with stickier tires was unable to climb that obstacle either.  

Over the (approximately) 7000 miles I’ve put on the RT03’s so far, which has included highway miles, and wheeling in New England, Colorado, and Moab, the tires have shown remarkably little wear. A five tire rotation was done at roughly 4000 miles, and the balance remains perfect. Overall the tires have lost roughly 1/32” of tread depth. They’ve also shown very little, if any trail damage. The sidewalls remain intact with no slices or cuts. The tread surface remains supple but uncut, and in all five tires I have only been able to find one torn lug, and it’s a tiny tear at that.

In summary, yes, I’m impressed with the Hankook DynaPro MT RT03. Soon they’ll be back on my trails and I’ll get a better understanding of how they handle New England granite, tree roots, and mud and I’ll be able to follow this article up with a wet weather assessment. But until then I’ll extend my wholehearted recommendation of the Hankook DynaPro MT RT03 to the masses of the Off-Road Nation.