I put on a new set of Kuhmo Ecsta SPT tires on my RX8, and I feel that the car rides really bad now. The tires seem to be tracking really bad on the highway, and feel very loose and not well planted. I went back to the place that mounted them, and they rechecked the balance, and I also had a 4 wheel realligned done.
That did not fix the issues. Could there be something actually wrong with the tires, and if so, how could I check that? Or could it be that the tires are just softer then the OEMS and just "feel" different?

Thanks

 

Do a search on them in the tire section. Kumho Ecsta SPTs are softer in the sidewall than the OEM tires. They do have better ride and noise level though.

Most people inflate them 1-4 pounds above Mazda recommended PSI. It stiffens the sidewalls and improves feel without wrecking better ride. They also last a long time.

 

i have the same tiers and never had a problem. they are alot softer than OEM and you can feel the differents. im running 38psi rear and 40psi front. i have no problems. hope you get everything straightend out cuz these tiers a pretty good.

 

I have driven with these tires on a 350Z and I have my nitto's on my 8 and they did feel weird to me too (also the feel of the 350) but I have never been a fan of Kuhmo at all....they are soft..

 

what air pressures are you running in the tires?

the spt tire does very well.. compared to the stock birdgestones, and the dunlop star specs i am running now..

beers

 

Are they the same size as your OEMs? I went to Kumho Ecsta ASX all weathers, but had to get 245 instead of 225. Sometimes they are hard to keep on the road because of the width difference - especially on the highway.

 

I'm running these tires on the street and they seem fine to me. For value, it's hard to beat Kuhmos.

Carefully check the tires sizes. You may have one or more tires of a different size. It happens.

 

i have these right now, they feel OK, no issues with sidewall.

the only issue i have with them is they develop flat spots when the tires cool, so the car can feel like i'm going over cobblestones for the first mile or two.

I use 32 psi.

 

I will choose different tires the next time. In the past couple years, there have been a lot more tires out in our size that are really great. You can't beat the price of the Kumhos, but they don't have the dry traction that some of the newer tires in stock size that also have good ride/noise and wear traits.

 

Have u ever tried 2-3 lbs higher?

 

What size and PSI are you running? And where are you in NNJ?

 

The tires I got are the same exact size as the OEM's. I have been running them with 32PSI, but I am going to add 3-4 PSI and see if that makes a difference. Some days they feel better then others, so it might be the outside temperature effecting the PSI.

Transam kid 01 - I live in Morris County, Jefferson Twp.

 

I can say my SPT's are MUCH better than the stock Dunlops as far as wet traction, and maybe a bit less for dry. The road noise is very low on them too, just as you said.

I'm running 35 psi, that changed the sidewall flex a lot over 32 psi.

 

I have these tires too.

Like already has been said, boost the PSI up a bit (I run mine at 35) - helps with the soft sidewalls and improves handling.

I've also noticed that (these tires or the car) get squirrelly on roads that are worn in with tire treads. If you're regularly driving roads that have indentations, this could also be some of what you're feeling. I will say, though, that I've only had Ecsta's , so I'm not sure if this is a result of the tire or just the feel of the car.

 

i had the same problem when i used them on now deceased 97 miata. i had to deflate them a little. but really good tires.

 

you guys run way higher psi then me. I have a digital reader and I always go about 28-30psi lol.

 

Wow - really low. Does it make the car feel soft? You might want to up the tire pressure a bit.

I run my SPTs around 34-35. Definitely tightens up the steering feel.

 

Am I insane for running my RE-01r's at like 38 psi, then?

 

Nope, as long as you like the feel, you're not getting dangerous with the pressure. Check the tires for even wear, though, just to be sure. Of course that is something to do no matter the pressure you run.

 

Modern tires can take a lot more pressure than that. It all depends on if you like the stiffer ride from them at that PSI.

On topic of SPTs, I think I'll get something else next time, but my mechanic says I have a lot of tread left. Guess that's what I get for buying tires with good treadlife.

 

I have those tires on my 8 - were on there when I got it. According to the seller, they had about 16k miles on them when I bought it and we've put another 1k on the car since we've had it. I may be crazy but it almost seems like I can see a difference in the tread wear after just that 1000 miles. If they are soft, I assume they would wear pretty quick. How many miles should I expect to get out of a set of these?

I'm not sure what pressures I'm running. I guess I should check. But my understanding is that you aren't supposed to exceed the Mazda PSI rating on the tires but it's technically okay to exceed it as long as you don't exceed the psi rating on the sidewall of the tire. What does Mazda recommend and what is supposed to be the max for these tires?

 

you cant be that lazy. seriously. go look at your door panel and go look on the sidewall of the tire.

 

^side wall usually only gives a MAX pressure which you don't want to run your tires at....I believe it's 32 on the door....but I run more

 

I just use these bad boys, when I see red I take a look

http://www.amazon.com/Perfect-Soluti.../dp/B000WS5SES

 

he asked for max pressure. which is on the sidewall