Challenge Khumo question

Which Khumo's are the best choice for the challenge?

They have to be DOT legal per the rules.

How long do they last if used as a road tire versus only being used for autocrossing?

Do they have a tech line so we can discuss tire application/performance?

Are they requiring Kumhos this year?

Their stickiest DOT autocross tire are the Ecsta V710s shown on the left. Their UTQG rating is 30 C A meaning they aren't expected to last long on the road and "C" have very poor wet braking performance.

The Ecsta XS's on the right are their extreme performance summer tires (UTQG 180 AA A). These work quite well for autocrossing in a narrow temperature range on dry pavement (they need a good amount of heat, but fall of quickly with too much heat.) I really wouldn't recommend them for driving on the street either.

Neither works very well for hard acceleration.

Not so much a requirement but Khumo's are budget exempt which makes them the only choice if you can swing the $.

So we are definitely going to need a pair of drag tires?

We want max autocross grip, is the V710 the, hands down, best choice and why?

Rule 25

Kumho Tires do not count towards the total budget. This is to thank Kumho for years of support for our event—and the fact that their tires kick ass.

Cool, I just read that rule change that Kumhos are budget exempt this year.

Yes, V710s are the fastest dry Kumho for autocross. Andy Hollis compared the V710s and XSes for GRM and found the former a couple of seconds faster on his Civic. They may not be as fast as Hoosier A6s or even Hankook Ventus Z214 C71s, but they are only fractional slower than those at worst, and they last a lot longer. They do fall off gradually, so bring newish ones. I've also heard the W710s are the fastest wet autocross tires period. So bring sets of both.

Kumho doesn't make drag tires as far as I am aware. A shaved set of Ecsta LE Sports might better than V710s for the drag portion. Or just budget a pair of non-Kumhos for the drag competition.

You will need drag slicks. Those Kuhmos will suck really really bad in the drags.

That rule is a real game changer...

Will Khumo have a tech present to help us tune the tire pressures according to car, weight, and temps?

With the grip levels potentially increasing there could be some real changes in lap times. Some cars may move wayyyy up in the standings with good tires.

From a safety view point be sure to check ALL brake components before the challenge. The cars will have more cornering force and could lift inside wheels sooner or pull studs/bolts out of hubs. Power will get to the ground earlier so straits will be faster brakes will have to work better.

Cars that were traction limited before could be really surprising now....

Alan

Does Kumho make a decent drag radial?

93gsxturbo wrote: Does Kumho make a decent drag radial?

I have heard they do not make a good drag tire.

Anybody from Kumho want to get in on this, its getting closer

MrJoshua wrote: You will need drag slicks. Those Kuhmos will suck really really bad in the drags.

The newfound budget room for the autocross tires will net most teams the ability to buy new bias-ply slicks (at least in the 14-15" range)...