Kumho V710 in real-life use at the race track...

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If you spend time in the autocross community, you’ve likely had experience with (or at least exposure to) Kumho’s V710 DOT-legal competition tire. With a treadwear rating of 30 and basically no tread pattern (two tiny grooves don’t count as a “pattern”), the V710 puts down tremendous grip. It has nicely-rounded shoulders to help camber-challenged cars (Tire Rack calls this “an inflated shape”), and it manages temperatures pretty well. Users tell me the V710 has a clearly-defined life term… that it simply “goes dead” after a certain number of heat cycles. Naturally, the number of heat cycles seems to vary, depending on who’s telling.

So, what happens when you reassign the V710 to road course duty? It wasn’t my plan from the start… I bought V710s in size 205/50/15, planning for a full season of autocross (averaging 2 events per month), and I intended to keep using Falken Azenis on the road courses. But my Azenis tires died and I wasn’t sure when the new ones were coming out, so I began to wonder if I could “get away with” using the V710s at an upcoming GVC-BMWCCA school at Watkins Glen.

I showed up at the Glen and it was wet, so I left crummy Dunlop 195/65/14 street tires mounted, thinking they’d be the smarter choice on a wet track. Besides, I’d never had this car on a road course before, and wanted to shake it out gradually. After a half-session in the morning, my instructor was whining about the Dunlops in an admonishing tone. “If you brought stickier tires, just put them on the car” he says. “OK, I’ve got some stickier tires for ya Buddy” was my only thought.

So I bolted on the V710s.

Holy cow. That’s a lot of grip! We’re talking about brand-new, green-as-they-get R-compounds, but they stuck like dog poop to a hardwood floor. Soon my instructor and I were trying to sort the chassis, knowing I’d never be able to fully utilize the V710s on a 325i with only springs, shocks, and camber-correction mounts. On this 55-degree day, they didn’t overheat, but they overpowered my brakes! Lockup and ABS activity during trail-braking became things of the past. After that Glen event, I added a larger front swaybar and fixed camber plates from Ireland Engineering, along with Hawk HT10 front pads (www.essexparts.com). Next came a VSR roll bar with Deist 6-point harnesses (www.stableenergies.com). These modifications were done solely to make better use of the grip offered by the V710s. For me it was certain: these tires needed to stay on the car for road-course events.

But would they last?

My car weighs 2600-2650 lbs with driver. I’d like to think this is light-duty for the V710s, considering some of the heavy-car applications I’ve seen in autocross. The V710s have lasted an entire season of road course driving. For me, this season included 6 days at Watkins Glen, 2 days at VIR, 2 days at Pocono North, and a day at Lime Rock. I didn’t use my V710s for autocross this year (mainly because I drove other people’s cars on V710s in autocross). At this season’s conclusion, there is still measurable tread-depth on each of the four tires. I used a very careful rotation schedule to ensure even wear.

How perfect are they?

Of course they’ll overheat when you screw up on a hot day (I’m thinking of this summer at VIR). The V710s will comfortably carry ridiculous slip angles for as long as you like, but as in autocross, the driver must remain conscientious of the rapid temperature build-up this causes. Drive with the tail tucked in, however, and it’s hard to fault these tires. So while you don’t look like Tiff Needel when making laps, your friends in traffic are amazed at the speed you carry into (and through) the corners. I even learned to love the V710s in the wet during a rainy session at Pocono North. On wet track surface, but without “standing water,” the grip was astounding… a couple of autocrossers have reported similar findings. Oh, and be sure to trim down those ludicrous slip angles when it rains.