I was invited to see these tires in action on some of California's most challenging trails and twisty highways in the San Bernardino Mountains near Big Bear Lake. We staged up early at the Knickerbocker Mansion Country Inn, where we were treated to a wonderful breakfast before we hit the trails and pavement. Our test fleet included a 2006 Nissan Xterra 4x4 and a 2007 Jeep Wrangler Unlimited equipped with Hankook RF10 All-Terrain Tires. I was excited to see the Jeep Wrangler Unlimited. I've taken Truck Trend's long-term Wrangler out on a few adventures on its stock tires, which gave me a base to judge how these new RF10s would handle.

We were in good hands for this trip. Our team was led by Don Alexander, who has quite the history as a respected test driver, writer, and racer. He holds the title for driving the world's fastest pickup truck at Bonneville in 2002, hitting 222.139 mph in the Gale Banks Sidewinder -- a Dodge Dakota with a 5.9-liter Cummins turbodiesel engine. Alexander lives to drive and has hit nearly all the trails in the San Bernardino Mountains and then some. Also on board was Malcolm Buckeridge who works with Don on creating a local off-road TV show and off-roading school.

Don and Malcolm started the trip by explaining their thoughts about these new tires. Our first run was a quick jaunt down the back side of the mountain on highway 18. I rode shotgun with Don in the Nissan Xterra as he whipped around the corners to show how the tires had the sticking ability to get around tight turns at average speeds. The RF10s performed as promised, with less noise than other all-terrain tires I've ridden on. I was impressed with the lack of humming on the highway. We switched seats once we reached the base of the mountain, and I worked my way back up the highway feeling the road in much the same way as before; once again the tires stuck to the road as a performance tire should.

According to Hankook representatives on our trip, the RF10s were designed to make daily on-road driving and off-roading more comfortable without compromising performance from either platform. I was impressed with the sticky grip of these tires as we ran up and down the highway. I've driven this highway more times than I can count. As an avid driver, my personal vehicle is setup with high-performance tires to handle these same curvy roads. I've also driven here in several different makes of SUVs. I was surprised that the RF10s felt as sporty as they did on the Xterra and Wrangler. I was able to take the corners and curves with ease, which I find harder to do in the other SUVs I've driven on this road.

The Dynapro RF10 ATs feature an all-new tread design with a seven-to-eight-percent-wider footprint over conventional all-terrains. This new tread involves an aggressive tiger-tooth pattern with deep wave kerfs to reduce heat, extend the tread life, and increase performance on wet roads. Another gripping additive is to the tread-block edge that features a zigzag cut that provides more grip in wet, icy, and dry conditions. Between the tread blocks, tiered side grooves provide less movement of the tread block for increase performance and safer cornering. The tiered side grooves also act as stone ejectors. Their step-like shape more easily expels rocks from the grooves to protect the tire and prevent damage without lost of traction. Scallop grooves between the tread blocks increase off-road traction with this new patent-pending design. The outer tread blocks also have angled side grooves on the exposed side just above the sidewall teeth, which enhance wet traction with a self-cleaning ability that easily pushes mud away.

The RF10s sidewalls have a thick, rugged, wraparound tread whose chunky teeth protect against punctures, cuts, and impact brakes while providing better traction on trails and in mud and snow. A larger rim cushion helps protect wheels from curb or rock damage. It also protects the redesigned sidewall from separation that might occur with low tire pressure. The sidewall of the tire is composed of a thicker-gauge rubber. When tire pressures are low, the thicker sidewall helps prevent the tire from folding and retains an almost full shape for even heat distribution and less wear.

We turned off the main road to air-down the tires to 19 psi. I jumped into the Jeep with Malcolm as my copilot. We continued for a few minutes down a tame dirt road on the mountainside, with Malcolm guiding me over our first set of rocky terrain. It wasn't difficult, but I was still wet behind the ears in off-roading. I soaked up anything he told me. The tires' sticky handling was apparent as we crept over the rocks. There was a strong, secure feeling of control that was missing the time I took our long-term Jeep off-roading.