: SVT Kumho tire issues; car fishtails on hwy
02-09-2008, 12:35 AM
I purcahsed a set of 4 Kumho ECSTA 215 45 17's and had a four wheel alignment and balancing when I first purchased them last summer. However, as the winter has rolled on, I've noticed that the car's handling can best be classified as "spooky". It's gotten to the point where the car fishtails on most road surfaces, and at all speeds, although it's more pronounced at highway speeds. But, it doesn't do this all the time, only sporadically. However, my girlfriend was following me the other day and swore I was sawing the wheel back and forth, the motion was that pronounced.
After a little while, I figured that maybe I hit a pothole or other road imperfection hard enough where it was causing the "odd" handling, so I brought it to a very reputable alignment shop and had them check the alignment as well as the caster/camber and my suspension; I do not have any damaged suspension parts. What the owner of the shop told me made sense, but I wanted to hear from other members as to their opinion on this.
What he told me was, although the ECSTAs are technically all-season tires, they do not perform well at below freezing temps, and the fact that we have such a small sidewall on the SVT's just exacerbates the issue. He further explained that the rubber compound on these tires is such that, at below freezing temps, it makes the tires perform like they are just kind of "skating" along sometimes.
I'm thinking of bringing the car for a "second opinion" elsewhere as I feel that there is an alignment issue, but I'm confused as whether or not that would solve the issue. The car tracks straight sometimes, and corners well....it almost seems like it's a bad case of tramlining/fishtailing at other times. Anyone else have similar issues with their tires? This is my first experience with an issue like this and am not sure how to proceed. BTW, the tire pressures are dead-on and there is no balancing issues ....the car drives smooth otherwise.
02-09-2008, 12:41 AM
I bought a set of Bridgestone Potenza G009's in 205/50/16 once and had to return them because they were like riding on water balloons. The back end would fishtail with any kind of aggressive maneuver. It was in summer though with no freezing temps. I took em back and got the Firehawk GT's and no more problem. But the owner of the shop said it was very odd and that they had never heard of this problem on those tires as they are supposed to be a "high performance" all season with a decent H rated sidewall. It doesn't quite sound exactly like your issue but similar i guess.
02-09-2008, 05:54 AM
granted my zetec isnt an svt but i share your problem. my fuzions also cause the same issue. the compound must literally freeze and then its like driving on a set of bowling balls right? if so thats how i feel. what you neeed is a set of 16 inch focus whels (why risk the 17's unless you have better wheels for summer...) and some of the pirelli p6 4 seasons. the main reason i suggest this is out cars have traction control. the priellis dont get so hard in winter so they are a lot more user freindly. (plus the tread design works a lot better in snow too). this will keep your svt's tcs from going into hyper mode when it starts to get slippery.and if you find the car getting dancy every time you slow down on the highway it's probably wise to back off a bit.
02-09-2008, 07:00 AM
It is definitely a tire issue.
The first thing I would check are the sidewall markings.
You are looking for the temperature rating. Tires have approved/rated operational temperatures.
Higher speed rated tires have MUCH higher temperature ratings. Rain and snow lower temperature. So, the Kuhmo you have may not be coming up to temperature to work properly.
The tire simply cannot get enough heat through the tread surface to enable the tire to grip properly.
Cold = hard and inflexible rubber. Hence your fishtailing.
Tire rack does a good job of explaining the markings. I tried to download the image, but it wouldn't let me.
You can find more HERE:
02-09-2008, 07:48 AM
I've got ContiExtreme Contact tires and have had no problems like you've described. They are a very soft compound and will flatspot, even over night. After a few miles, they smooth back out. They're also relatively inexpensive < $100 US and are "W" speed rated (170MPH)
What a drag it would be to have a handling problem in a SVT though.
02-09-2008, 12:56 PM
Thanks for the input!!
WeeAsp....after I read your response, I started doing some searches on speed ratings/tire wear, etc.....and found you absolutely "hit the nail on the head". I spent hours researching tire wear ratings, handling, price, etc. and never thought I'd have an issue like this. Checking more on this tire, showed that, while it will work icolder temps, it is not "recommended" as a winter tire because of the bricklike 400 treadwear rating as well as the ZR speed rating. Of course, the morons I bought it from could care less about my application, they just want to make the sale.
It's funny, I ve owned : 5.0L Mustang, IROC-Z, SE-R, Probe GT, SVT Contour, et al. and have used ALL kinds of high performance tires over the years and have NEVER run into an issue like this!! Many of the above cars had some sort of "summer performance" tire (e.g HR, VR, ZR rated)that one would figure would cause the issues I'm having. The really ironic thing is that these Kumhos actually perform quite admirably in the snow! Well, I guess, unless you are TOTALLY dense, that you "learn something everday"....I just learned a very expensive lesson!
Killer ZETEC...thanks for your response, but my SVT came stock with the Argent EAP rims and tires, which are 17's. You point is well taken with the smaller rim diameter...I may look into 15 or 16 inch rims next year with dedicated "winter tires" (e.g. Blizzaks, etc.).
Basically, I'm stuck with these tires right now...being a single Dad, who's going back onto Active Duty in a few weeks at a "pending" E-5 rate of pay, doesn't lend itself to buying much except for food, gas, etc.
02-09-2008, 02:02 PM
i know u said you got an alignment, but what exactly are you rear toe settings? If they are near the outer edge of "within spec" they might be causing or contributing to your wagging ass end of the car. I know that when i lowered my focus and before i got an alignment to fix the toe, my car would wobble like that on snowy roads. To fix it i set the rear toe to 0. i've had no problems since.
02-09-2008, 02:19 PM
I noticed that problem with my Falkens when I drove on them when it was really cold. With my Dunlop Winter Sport's it's perfect. Even if it's not snowing winter tires are a good idea if you live in a cold climate.
02-09-2008, 04:23 PM
Could you clarify which Ecsta model you have. Kumho makes about a dozen Ecsta models. There should be some letters on the sidewall like AST, ASX, SPT, etc. This would help pinpoint the model and its intended operational characteristics.
02-10-2008, 03:07 PM
Here's a tip. Don't run summer tires in the cold.
02-10-2008, 05:23 PM
Hey, thanks for the feedback, guys!
Grey, you are absolutely right, but, with the Kumhos I have (AST's link)
I figured that they were the best comprimise between price/performance that i could find...plus, I figured that the H-rating (I screwed up my earlier post-they aren't ZR rated) would mean that the tires wouldn't have the issues that say a VR or ZR tire would have in the snow. What I didn't realize was that, with it's bricklike 400 treadwear rating, they aren't exactly the best tire for when the mercury drops.
My toe in toe out is exactly zero....that was one of the first things I had the alignment shop check, as I figured that was the first thing that would cause the wierd handling.
Again, Life is a series of learning experiences, and I just learned another valuable lesson about tires...[B)]
02-10-2008, 06:00 PM
We have AST's on our Focus and they don't have the problems you described. We do have an Eibach pro system and a carefully thought out alignment with a little toe out in the front and a little toe-in in the rear with moderate camber angles. In addition i would not call these tires "brick like". The 400 tread wear doesn't really mean a lot in terms for tire firmness. Our old Ecsta 711's were much stiffer than these and had a lower tread wear rating (if i remember correctly). What tire pressures are you running?
02-10-2008, 10:11 PM
Here's a tip. Don't run summer tires in the cold.
Couldn't have said it better myself! I recently put my stock wheels back on with winter tires after experiencing some scary driving on Kumho Ecsta AST's. You are right. It's like they lose all grip when the weather gets cold. I'm saving them for the summer when I can get that rubber nice and hot!
02-10-2008, 10:26 PM
I have the khumo 711's and i can do a 100 foot burn out in the cold and i've got an auto haha =)
02-11-2008, 05:02 PM
Well, the tire pressures I'm running factory spec....32 psi front, 29 psi rear...other than that, nothing out of the ordinary with suspension settings, etc. That being said, I would assume that the suspension took/takes abeating on the roads out here and will need an alignment in the Spring after the frost heaves go away....
Rear alignment is your most likely culprit.
You want minimum camber, and minimum toe in, which is .04 according to the specs.
02-11-2008, 05:24 PM
Here's a tip. Don't run summer tires in the cold.
[rolleyes] Such wonderful input as always....[rolleyes]
There should be a guide in this place that lists tried brands and our opinions on performance.
My contribution to that hypothetical chart would put Fuzions on the no-no list for winter driving. Their supersoft compound (hence the lack of a warranty) will not heat up properly in cold climates and result in fishtailing, even with substantial tread left on them.
02-11-2008, 06:06 PM
yai agree...get winter tires dude...
its gotta be a tire problem.
02-16-2008, 08:05 AM
as I don't have the $$ to get another dedicated winter set right now, it would appear that I'm stuck with these for the forseeable future.
WD, thanks for the input as well as everyone else who opined about the rear suspension settings...that is something I will definitely do in the Spring...no sense doing it no with the apearance of so many potholes around here lately...gotta love winter in New england!