Kumho Ecsta Supra 712
Well, I have a couple weeks and about 2000 miles on the new Kumhos.
My initial reaction is WOW! Wierd tire design for the street. Built like a race tire with a real soft tread construction and STIFFFFFFFF sidewall layers. The compound used is sticky but not soft and the Tread wear is rated at 280 (we'll see how they wear). They are quiter than any tire I have ever run and the Old Buggers transmit road noise to the cabin much more than the newer cars so that's important. The quiet running extends all the way to the traction limit until the onset of breakaway where there is a slight scrub and then a small squeal in some conditions. For the last couple days I have finally had a chance to experiment with wet grip and they are amazing. I chose these tires over the RE730 because I thought the tread design was more advanced and the reviews and comments I heard were pointing to a tire that didn't give up as much dry traction to get longer life. Also, because of the sizes available specifically 225/40 and 225/45 and 225/50 for 16".
The wierdest part is the tire pressures I am running cold. I have run 40 front and 36 rear in my RE71 for a season and a half and 40 in all corners with the old phone dials and D40s. That was after much experimenting. With these new tires I started at 38 front and 36 rear mainly because I have a 5% lower profile in the front this time. The car was unmanageable and the rear was loose. I pulled the car up in my garage and could see the problem immediately. I was only using about 2/3 of the contact patch in the rear. So I started letting air out and ripping down the 4 miles of corners in my favorite canyon. I chalked the sidewalls as I went and let out air in a couple of pound increments. In the end I had 32 front and 30 rear. I have been flogging the car pretty hard and it seems to be running and handling perfectly. The tires are not rolling over at these pressures and the old palm pyrometer is telling me that the center of the contact patch is anchored.
So here's the deal: They are just awesome and they are dirt cheap. If they wear like they are rated to wear I may put them on my Audi next summer. They are available in all kinds of sizes and profiles too so they seem to be tailoring them to the tweeker. BTW I am running 225/45 ZR16 W63 on 16 x 7.5 and 245/45 ZR16 W89 on 16 x 9 Design 90 wheels. It's just a different car now!
79 US 5 speed
I put on new tires a couple of weeks ago. In choosing a tire I was interested in the cheapest thing available in my needed 17" sizes. I searched TireRack, Discount Tire and TiresOnline and found the Kumho ECSTA Supra 712. I was amazed at the prices on these tires. They were consistently the least expensive high performance tire available. In my sizes, 245/40/17 Front & 265/40/17 Rear, they were $105 and $124 each respectively. I ended up purchasing them from my local shop (Tires Plus) and ended up with tax, a little shipping and mounting/balancing a total of under $550!!!
Previously I have been an ardent supporter of the Firehawk SZ50. But the Kumhos are wwaayy quieter and wwaayy cheaper. So far I am very impressed with the tires. Haven't had them in the rain yet so I can't comment on that. Also, I used to run teh SZ50s at 42 psi front and 40 psi rear and had a reasonable ride. The Kumhos are too harsh at those pressures. They seem to ride much better at 36 psi front and 34 psi rear.
I have no vested interest in these tires or Kumho....just thought I would pass along the data. Tires for our cars can be very expensive and although they may not be quite as sticky as S0-3s, I can go through 2 complete sets of the Kumhos and have change left over (or get a set of track tires!)
Michael G. Wachholz
The only negative I have heard about the new street Kumho is that they are too stiff. for at least one street car old bugger owner I conversed with they were just too darned stiff. But he changed from a regular tire on a stock rim to 17" and the new Kumho's all at once so I can understand his bewilderment. Going from cush to kidney belt ride quality is always an eye opener. On my car I changed from RE71's on 16" design 90's and there is just no comparison. Quiet, wearing like iron, grip like a leach to quote another 914 owning lister, dry and wet, great updated vectoresque tread design, 180 something miles an hour rating, stiff sidewall but good ride, available in all kinds of widths and profiles and rim sizes... and to top it all off dirt cheap. Why would anyone want another tire for the street unless they wanted to trade that last little bit of grip for no life and wanted a "real" brand name. I am about 8k miles into my first set of them and they are still going strong and I will buy another set when they are done. They are the first tire that has gotten to the end of the second summer on my car so far.
The real surprise for me has been the relative sticky and soft feel with the high tread wear rating. I didn't believe it at first but it seems to be panning out.
I reluctanly jumped into a set of Kumhos ECSTA 712's after running both the Michelin Pilots and Birdstone RE730's on my 2000 328i. Switched to the new Kumho ECSTA 712's. For about 100 bucks cheaper per tire - Found them to be as good, IF NOT BETTER, than my Michelins and Birdstones. Cheapest ZR rated tire on the market and Specs out better than most. I have not looked back since and I am quite satisfied. They are going on my 993 as soon as the lousy Dunlop SP8000"s start to show a little bit more wear.
As for the Yokohama db I have not run that tire yet but have run the AVS S1-Z and AVS Sport. Great Tires (AVS Sport) but EXPENSIVE! However stay away from the Yokohama Sport S1-Z (discontinued anyway) the wet weather traction of the S1-Z is very poor, especially in the wet. I used them both on my 928.
I personally beleive the Kumho ECSTA 712's can compare easily for tread wear (much longer than the Yoko), wet and dry weather performance. The Kumho are remarkably sticky and when you toss in the price I think nothing comes even close.
The problem with the Kumho's is they are "FLYING OFF THE SHELVES" I had to drive from Hillsboro, Oregon to Gresham, Oregan (about 35miles cross-town) just to get mine becuase all the dealers here in area were "sold out" except one!
1996 993 Cabriolet- Polar Silver (trade for a mint condition 94/95 928GTS)
2001 BMW 325I
Former Owner of "The Predator"
1985 928S 5Spd Garnet Red
Ott Performance Engineering Exhaust & Drop Links, Bilstein & Eibachs, S4
Brakes,variable brake proportioning, and a loud azz RMB "nutt'n but pipe!"
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