Locke

Maybe I've been hiding under a rock but I've just noticed a new offering in high performace tires that fit the rears of our C-4s with the 11" wheels.
Those of us autocrossing in the street tire, stock class have had the Goodyear Eagle F1 and the Sumitomo HTR Z to choose from. The Goodyear is pretty good but expensive and the Sumitomo is priced great but the grip seemed to be what you paid for.
Has anyone tried the new Ecsta XS?

rasrboy

Hey buddy,

I am over at Road Atlanta for the Walter Mitty doing a ride and drive program on the back skid pad area. We have 3 mazda's with the new XS
on them and I must say they ROCK!

If you were closer, we have this open to the public sat from 10-5 but today is for our dealers. Sunday we head back to Ohio.

If anyone here from the forum is in the area tomorrow (sat), stop by and say hi and try the cars out. Best part is it's FREE!

Aaron Quine
Kumho Tire (Motorsports)

sgsvette

Aaron,
I'm going to take you up on your offer since I happen to be at Road Atlanta also, and have never driven a Miatta.

Locke,

The XS is a great tire with lots of grip, get them! I use them on a Corvette also and besides great grip the price blows the competition away.

95jersey

Can you provide a comparison? Great grip compared to what? An expensive set of street tires or Hoosiers? I am thinking for sure they are not as good as Hoosiers, but like to hear how close. I would bet they would probably last much longer.

Oobus

I've got a set on my LS1 RX7 and really like them. Tons of grip (when warm), they don't tram and sidewall stifness is good. I would not put them on a car that is driven in cold areas. I've only had them on for about 1,000m, but so far they seem like a great tire for the $. I think the grip was better than my S03's.

Z06_BluByU

a few years ago when they came out with the new MX tire i tried that... and it was the most awful tire i ever had on my C4..

except maybe those crappy futura pep boys garbage the car came with..

sgsvette

:Without getting to technical, simply put: XS street tire compared to most street tires has great grip. Not as good as the Hoosier? Well, let's compare apples to apples: Hoosier DOT race tire vs Kumho DOT race tire. One will be a little better than the other and everyone you talk to will give you a different opinion. I personally like the Kumho better.
Unless you are out there trying to get every hundreds of a second out of your car, it really doesn't matter which of the two brands you use. Driver talent has more to do with lap times than tires.

GrantB

I posted a review here. They probably aren't quite as sticky as Direzza Star Specs or RE11s, but are stickier than nearly every other street tire. They do overheat more easily than MXs and fall off pretty quickly when hot (despite Kumho's claims of the tire being optimal at 203F, my stopwatch and DAQ showed significant drop in performance by 190F).

Wear is very good. After four track days, mine are only about half gone (I typically only get about 4000 miles out of my tires; a mix of track and street driving).

trackboss

I'd buy these now for the street if they offered a 295/35-18. I've called kumho to try and get an answer whether they will make them and they wouldn't say. They make a 305/30-18, but it is a tad smaller diameter than the 275/35-18 I run on the front. I'd personally rather run a taller rear tire. Is there any way to push kumho to make more sizes? They offer the size I need in the mx so why not the xs?

MySR71

The latest issue of Grassroots Motorsports (which I just got today in the mail) has a review of these vs. Falken R615's and others. The Kumhos won their street tire test.

PA Z06

I almost bought them, but noone had the sizes I needed. I bought the new nitto's nts instead.

avizandum

I have Star Specs on the front and XSs on the rear. A guy who was chasing me all last year smoked me at the first event of this year and he has XSs all around.

I took a ride with him and he could brake much later and deeper into the corners. I was really impressed and will be putting the XSs up front when the Dunlops wear out.

They do require a little warming up and the Dunlops don't FWIW.

This was AutoX, so I don't know how they would deal with track temps.

bse53

I've got to decide soon what to put on my C4 this year (for the events I don't want to drag dot-R tires to).
I was ready to buy NT-05's when I read that they are narrow (section width 10.79" vs 11" for the Kumho XS). In addition if you look at the cross section, the actual tread on the ground is narrower than the XS also (more like an old set of AD032's I have).
But if this statement is true: tire compound > tire width the NT05 might still be a good tire.
I've ruled out Toyo's R1R, so the only choices are XS and NT05.

NT05's have slightly less tread depth new (which should make the tire more responsive new).
Which tire has stiffer sidewalls?
Is the NT05 tire compound stickier than the XS?
Will the slightly wider tread width of the XS translate to better cornering grip?
Which tire heats up quicker?
Is the NT05 a better tire for track days and the XS better for autocross?

I hope these questions aren't hijacking this thread.

Brian