| ULTRA HIGH-PERFORMANCE |
| WHAT: | KUMHO ECSTA MX |
| WHERE: | ENGLISHTOWN, NJ |
| HOW IT WAS TESTED: | DRY SKIDPAD |
| TEST VEHICLE: | 2005 GTO LS2 SIX-SPEED |
Tire Details:
245/40/18, Z rated, 220 treadwear rating, traction AA, temperature A, $660. The Ecsta uses advanced Silica tread compounds combined with directional tread design for accelerating, braking, and cornering prowess. Cornering is further enhanced with two wide steel belts, and nylon cap plies provide high-speed stability. A Rim Protector in the lower sidewall protects against wheel scratches.
Testing:
GMHTP's own LS2 GTO would be the tester, equipped with the factory 17-inch rims/tires. However, our Goat had several suspension upgrades from SLP; a bigger 19mm rear stabilizer bar, progressive rate lowering springs, poly end-link bushings, and a rear camber kit. Previous stock-suspension g-testing showed a .85g average; on this day with the SLP suspension, we recorded a .85g clockwise, .90g counter-clockwise, for an average of .87g.
In preparing for this test, we searched for an affordable 18-inch rim that would not only fit in the GTO's tiny wheelwells, but look great doing it. The Tire Rack was up to the challenge, supplying GMHTP with not only the kumho rubber, but the awesome ASA ST4 rims as well. This complex 5-spoke design came in an 18x8 size, with a silver finish and a machined lip. At 24 pounds, the 18-inch ST4 is lighter than the stock 17. And at only $199/each, practically a steal. The ST4s and Ecsta MXs showed up already mounted and fully balanced, and were soon put to the test at Etown -once they were bolted down and warmed up, we hit the record button and started turning gs. For the clockwise laps we saw .89g, and for the counter-clockwise runs, .91g. That turned into an average of .90g, a .030g improvement.
With the SLP suspension, the Real-World Skidpad was too rough to confidently hold our modded 'Goat at the limit. Though the 18-inch ASAs and kumho tires really did a number to the understeer, and the kumhos proved extremely sticky on smoother portions of the 'pad, the modified suspension couldn't calm the worst patches, and the maximum g-force suffered. It was still a great-handling tire, and a sweetlooking rim/tire combo.