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g-Tires for Your g-Machine

Kumho strikes back at the outrageous cost of ultra high performance tires

Johnny Hunkins Nov 24, 2004
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Every year, tire manufacturers battle it out for the top billing in the performance tire biz. Household names like Goodyear, Michelin and Pirelli spend millions of dollars on research and development, motorsport sponsorship and advertising to make sure they stay on top while making sure you know they're on top. And while you can surely be proud to say one of these top manufacturers is branded on the sidewalls of your g-Machine, there is a price to pay for name recognition.

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We were able to sample some of the new Kumho tires on three-identically prepared Minis. Underpowered and packing an automatic transmission, we charitably refer to these as "momentum cars." Still, it was enough to get a feel for Kumho's new MX ultra high-performance street tire and the new Ecsta V710 competition tire.

For years, Asian tire manufacturers have waited quietly on the sideline, providing competent products at a bargain price without creating a lot of attention. In the last few years, however, that has changed as many bit players in the market have improved their quality, their performance and especially their brand awareness with a younger crowd. To many enthusiasts under 30, a name like Kumho is just as big as Goodyear, and that may come as a shock to many older hot rodders.

South Korean tire manufacturer Kumho has historically been a worldwide producer of industrial and truck tires. But in the early '90s, the industrial giant decided to explore the world of performance tires with its breakthrough Victoracer V700, now a staple of club racers everywhere. As more high-performance street products filtered into the mix, Kumho quietly became the ninth-largest tire manufacturer in the world. And as 2004 comes to a close, the Korean company has just introduced even more performance products which must be considered seriously for your g-Machine.

We recently got a chance to sample some of these new wares at Fontana Speedway in California, and we were impressed. We got the chance to sample the entire array of Kumho performance products on an autocross course with a trio of identically prepared Minis. (Sure, we know they aren't true g-Machines, but these days Chevy is runnin' kinda low on LS1 Camaros!) We were offered the opportunity to sample a number of tires ranging from the relatively tame all-season Ecsta HP4 to the all-out street-legal-in-name-only competition Ecsta V710. In between, we got to try out the sure-footed Ecsta Supra 712, the ultra-high performance Ecsta MX, the fully treaded competition Ecsta V700 and our old friend, the competition Victoracer V700. Since PHR is all about full-bore performance, we're only going to look closely at the most aggressive street tire (the MX) and the new competition tires (Ecsta V700 and Ecsta V710).

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The Kumho MX is a serious low-cost contender for the Goodyear F1 Supercar tire, the BF Goodrich g-Force T/A KD and the Michelin Pilot Sport--which cost nearly twice as much as the MX. This is a max-effort street tire that has 80-85 percent of the grip of a competition DOT-approved tire and is made in all the serious sizes required by g-Machine musclecars.

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Originally intended as the replacement for the aging V700 Victoracer, the Ecsta V700 features an advanced silica tread, a lighter carcass and a symmetrical tread to enable rim reversal (swapping from side to side) for increased tire wear. Besides club racing, the Ecsta V700 is a great alternative to a drag radial on a street car since nobody will have the slightest idea what it is!

Ecsta MX

Kumho has done its homework with this new ultra high performance street tire by aiming squarely at the best in class: the BF Goodrich g-Force T/A KD, the Goodyear Eagle F1 Supercar and the Michelin Pilot Sport. While not full-on competition tires, all of these exhibit many of the traits of competition tires such as softer rubber compounds, aggressive dry weather tread patterns, and reinforced sidewalls for elevated lateral loads. With grip approaching 80 to 85 percent of a treaded DOT-legal competition tire, this class of tires has little down side, except for price. Obviously, these aren't tires that fare all that well in inclement weather, but they serve well enough to do the job adequately (i.e. don't put 'em on the wife's daily driver).

Although these other tires weren't available for us to test on the same day, we have recently spent time behind the wheel with the BF Goodrich KD (at Putnam Park Road Course with Paul Svinicki's Ignitor Mustang), the Goodyear Supercar (on a Z06 Corvette at Mid-Ohio Road Course) and the Michelin Pilot (at GingerMan Raceway with a 525-hp Cadillac CTS-V). Before sampling the Kumho MX, we didn't think the upstart MX could hang with the others (some of which cost nearly twice as much), but we were very wrong.

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The Kumho Victoracer V700 DOT-approved competition tire came out in 1993 and quickly became the darling of club racers everywhere for its impressive race tire grip and affordable price. It's still sold today, but is now complimented by the newer Ecsta V700 and Ecsta V710.

The little Mini with MX skins--thanks to an advanced silica tread--had tenacious grip on the dusty autocross course, but perhaps the most remarkable trait was how well this tire communicates its disposition. We found no surprises near the limit of handling. The MX doesn't let go suddenly when its limit is reached; it telegraphs the loss progressively with audible warnings and benign understeer. There is no Hail Mary loss of grip; no big change in adhesion at higher temperatures and no chunking after continuous lateral punishment. We would feel completely comfortable at speed with the MX on a high-speed track like Mid-Ohio or Watkins Glen where the wall is sometimes inches from the racing surface. If you're looking for a good dual-purpose street/track day tire in a max-effort street car, the MX is a cost-effective alternative to the Michelin Pilot Sport, the Goodyear Eagle F1 Supercar or the BFG g-Force KD. Without a direct comparison, we can't say the MX was empirically better, but it felt so good that we are very confident in placing it in the same category with these class leaders. The money you save will easily pay for the more aggressive track-day brake pads you'll need with the extra grip.

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The Kumho MX is a serious low-cost contender for the Goodyear F1 Supercar tire, the BF Goodrich g-Force T/A KD and the Michelin Pilot Sport--which cost nearly twice as much as the MX. This is a max-effort street tire that has 80-85 percent of the grip of a competition DOT-approved tire and is made in all the serious sizes required by g-Machine musclecars.

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Originally intended as the replacement for the aging V700 Victoracer, the Ecsta V700 features an advanced silica tread, a lighter carcass and a symmetrical tread to enable rim reversal (swapping from side to side) for increased tire wear. Besides club racing, the Ecsta V700 is a great alternative to a drag radial on a street car since nobody will have the slightest idea what it is!

Ecsta V700

When the original Kumho Victoracer V700 was released in 1993, it changed the club racing scene for good, and for the better. No longer would conglomerate tire companies be able to charge the little guy exorbitant amounts for DOT-approved competition tires. The Victoracer has soldiered on to this day (it is still being manufactured and actively raced) but has become somewhat dated by newer DOT-approved competition tires by Hoosier, BF Goodrich, Nitto and even South Korean competitor Hankook. While still a great deal for the dollar, the Victoracer was losing its competitive edge--until the Ecsta V700 made its appearance.

The Ecsta V700 differs from the Victoracer in that it is lighter (an obvious competitive advantage) and possesses a symmetrical tread pattern which can be remounted (reversed from side-to-side) for additional life expectancy. An advanced silica tread provides excellent repeatability and sustained grip after multiple heat cycles--unlike its predecessor, the Victoracer.

Our encounter with the Ecsta V700 occurred in the passenger seat of several Pro Solo and T1 prepared C4 and C5 Corvettes (Kumho didn't want to press its luck with the mostly green journalists in attendance), so our impression of this tire isn't as nailed down as it could've been, but we were impressed nonetheless. We were fortunate enough to be escorted around Fontana's temporary course by SCCA drivers Scotty White and Cindi Lux of NayKid Racing. No quarter was spared in putting the group of Corvettes right up to the limit.

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Kumho is active in SCCA racing and sponsors the NayKid Racing ZO6s of Scotty White (shown) and Cindi Lux. Both now run the Ecsta V710 competition tire (a slick with grooves for DOT approval) in the T1 class.

The new Ecsta 700 is Kumho's bread-and-butter competition tire, and as such it has a real tread pattern that can be used on the street without raising eyebrows among law enforcement. A tire like this is the maximum strength possible on a street car. Soft enough to generate the same grip as a drag radial (it has a treadwear rating of 50), it has the added benefit of being totally unexpected by the Nitto, Mickey Thompson and BFG drag radial cognoscenti. (Hint: If hooking up a sucker bet street race is your cup of tea, try the Ecsta V700 instead of a name brand drag radial. Nobody will be the wiser.)

Back in the 'Vettes, we were happy to see that the Ecsta V700 could be tossed pretty much sideways while maintaining whatever level of control the driver possessed to start with. And trust us, it takes a lot of throwing to turn a C5 sideways with a set of Ecsta V700s. Scotty and Cindi were able to put a lot of heat into the skins due to the longer and more complex course being used for the Corvettes. Based on our previous experience with the older Victoracer, we don't think the Victoracer would've maintained its grip toward the end of the course. The Z06, in particular, has a lot of torque which can really blister an outside rear tire on corner exit. We didn't notice any oiliness or loss of grip with the Ecsta V700 as we've experienced in the past with the Victoracer. We would've liked to try the Ecsta V700 and the next tire--the Ecsta V710--on a full road course, as this is where both of these tires would really shine.

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Kumho is serving notice to its race tire competitors with the new Ecsta V710. It's a no-holds-barred slick, with a pair of 4/32-inch grooves for DOT compliance. This tire is going to give the Goodyear GS-CS and the Hoosier R3S04 fits in SCCA classes across the country--and at a scandalously low price.

Ecsta V710

Once again, we were treated to a ride-along with Scotty White and Cindi Lux, this time with a Z06 shod with the Ecsta V710. The V710 is for all practical purposes a slick with two circumferential grooves--the minimum needed for DOT approval. Even with the DOT rating, there's no way this is gonna slip by the cops, so don't even try. Still, you'll be tempted, because these things grip like a full racing slick (which it is).

The V710 was introduced last year after a pretty unspectacular year of racing (for Kumho) the year prior. Essentially, the brass at Kumho were sitting around one day at the SCCA run-offs at Mid-Ohio, commiserating about what happened to all the class wins they used to get. Other tires had come from behind over the years and they figured it was now time to do something about it--namely the V710.

The Kumho press kit says the V710 is lighter and faster than its two predecessors (the Victoracer and the Ecsta V700), but truthfully, it has no predecessors. Neither the Victoracer nor the Ecsta V700 are true slicks, and they certainly don't have the ultra-sticky (and ultra short-lived) compound (the V710 has a treadwear rating of 30). The only rear competition for this tire is a true slick from Goodyear, Dunlop or Hoosier. The only difference? You'll have enough money to take on four tires at that pitstop instead of just two! The V710 does not need to be shaved for best grip, although a heat cycling is best prior to serious competition.

In the shotgun seat of the T1 prepped NayKid Racing Z06, the grip of the V710s seemed to have no limit at all. In fact, our photo of the car in a high-speed right-hand sweeper shows the front right tire completely off the ground. The V710 does have a limit somewhere out there, but we didn't find it in the passenger seat--and we didn't find it in the Mini we drove later.

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How much grip does the Ecsta V710 have? Check out the front right tire which is completely off the ground in this dusty parking lot.

The V710-shod Mini was a great litmus test for the V710. With an automatic transmission and no blower, our Mini is what we would charitably call a "momentum car." Readers of Popular Hot Rodding might find this hard to believe, but there's a whole world of racers out there who actually prefer to drive cars with no power--and most of them drive imports like the Mini. Basically, you've got to carry a lot of speed through the corners without screwing up. (No speed, no good lap time. Too much speed, no lap time at all.) It's a fine line that rewards a good driver with a good tire--but the better the tire, the less it matters that the driver is good. That certainly was the case with us, as we managed to look like consummate pros behind the wheel of the Mini--thanks to the V710.

Few people have ever driven a handling car with a true slick, but once you do, it's in your blood forever. If this is you, you've got to try the V710--especially if you're already on the Hoosiers (R3S04) or Goodyears (GS-CS). Club racers and autocrossers take note: the V710 is going to equal the best racing slicks in 2005 all while being the best bang for the buck, so if you're considering a few sets of fresh race rubber for the spring, take a look at the Kumho V710--you owe it to yourself to try at least one set.

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Here's the Kumho MX in action. The tire communicates well at the limit and doesn't complain. The tire gets up to temperature quickly and doesn't chunk under heavy lateral loads such as found in autocrossing--that's due to its advanced silica coumpound.

SummaryWith these three new tires from Kumho, it's plain to see that they aren't messing around when it comes to maximum grip at a budget price. For most serious street cars, the MX is going to be the best bet 70 percent of the time. As you can see from the size chart, Kumho is really taking care of the g-Machines out there with the 17-, 18- and 19-inch rims. And they're wide too. Most manufacturers make plenty of big-inch rim sizes, but you can always tell the men from the boys when it comes to width--and Kumho doesn't disappoint.For the guys in the top 30 percent bracket, the Ecsta V700 is the way to go. You're going to get 95 percent of the grip found in a full race tire, but enough tread void to negotiate the occasional drizzle. With a good set of brakes, look for stopping distance from 60 mph in the 110-115 foot range for the typical g-Machine. Likewise, you won't have to worry about holding your own at the Friday night test and tune. The Ecsta V700 has serious grip along the lines of Nitto, BFG and Mickey Thompson drag radials. Only they go around corners too.

If you're in the top 5 percent, the V710 is your tire--but don't think about running it on the street. Mount 'em on a second set of rims and change them at the road race track or the autocross. You'll be blowing past cars with street tires that have a lot more power. If it were us, we'd get a little tag-along trailer to tow the tires behind your street car. That ought to make the point!


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