Summer Rubber: Testing performance tires from Hankook and Kumho

With summer in full swing, you've probably already been to an autocross or an open track day this year. And you're either glad you picked up that new set of tires--or really bummed that you didn't. As any performance driver will tell you, tires are the single most important factor in determining how well or how poorly a car performs.

So if you're a racer who attempted to squeeze another season out of some tired rubber with disappointing results, you can still spring for new tires now and salvage the second half of the year.

Over the past few months, we were invited to sample some performance tire offerings from Hankook and Kumho and came away contemplating making one of them the next tire we put on our own weekend racer.

Hankook Ventus V12 evo

Hankook has been making plenty of headway in the tire industry winning OE supplier contracts with the likes of Ford, GM, Hyundai, Kia, Volkswagen and Chrysler, but it's also been active in the performance and motorsports arenas. In the past, it's participated in the American Le Mans Series and continues to support drifting with its Ventus family of tires.

We tested the Hankook Ventus V12 evo against the Bridgestone Potenza RE760 Sport on a dry autocross course with a lane change section, slalom, 180-degree turn and fast sweeping right- and left-handers on identical Mustang GTs. Through all the exercises, the Hankooks were more predictable, responded faster to steering inputs and offered more grip through the fast portions of the course. The Bridgestones still offered respectable performance, but compared to the Hankooks, they understeered more and weren't as quick to change direction.

Hankook's explanation for its superior performance comes down to a number of things. Engineers first credited the V12 evo's 3D tread block edges and continuous center rib which provides optimal ground contact pressure to improve response and brake performance. Much credit also went to the evo's construction, which utilizes twin steel belts reinforced with two-ply nylon and a lower side wall made from hard rubber with steel reinforcement (Bridgestone only uses hard rubber for its lower side wall).

We didn't get a chance to test the V12 evo's wet weather performance, but Hankook says the tread's wide linear grooves and Y-shaped pattern make it efficiently channel water away from the tire for good wet weather performance.

On top of all that, Hankook representatives say that the Ventus V12 evo retails on average between 15 to 20 percent cheaper than the Bridgestone, which makes it a mighty enticing tire for both its performance and value.

Kumho Ecsta XS

Another high-performance Korean tire that we strongly suggest checking out is Kumho's Ecsta XS, which launched last fall to replace the aging Ecsta MX. Changes to the XS include an asymmetric tread design, flatter center tread design for a maximum footprint and an ultra fine carbon black tread compound for improved traction and better heat management. Additional features include a solid center tread rib for better steering response and rim protector bars on all size tires.

We spent a day wringing out the XS at Mid-Ohio Sports Car Course on an autocross and hot lapping the 2.4-mile road course. We also got the chance to sample the older MX to compare the new against the old. On the autocross, we drove Acura TSXs and Honda S2000s and could easily pick up the differences. The XS offered much more grip in the corners with better response at turn-in. After only a few loops around the course, we were pushing it really hard. The XS did not disappoint and were noticeably quieter giving off less tire squeal when pushed to the limit compared to the MX. In the S2000, we ended up being 0.8-seconds faster around the short autocross on the XS than on the MX.

For the hot laps, we really put the improved heat management of the tread compound to the test. In addition to the heavy flogging, the tires had to deal with hot outside temps. After roughly 10 laps of the road course, the tires showed no signs of going away and stayed consistently good the entire time. The stellar performance allowed us to build a good amount of confidence behind the wheel at a track we had never been on prior and do surprisingly well.

One of the tires Kumho cited as a main competitor is the Falken Azenis RT-615, which happen to be the tires on this writer's personal 1994 Mazda RX-7. We were so impressed with the Ecsta XS that they probably will be replacing our Falkens soon. Count us as a conquest sale.

(autoweek.com)