DamonB

I needed new street rubber for my stock wheels and decided to try the Kumho MX in 225/50/16 (no 245 made). They've only been on a few days but so far I like them for $103 apiece. First thing I noticed before even putting them on is that the sidewall and the rest of the tire carcass is very flexible.

They do have very large tread blocks and so make a low, drumming sound at highway speeds; it's not obtrusive IMO but I can hear it. The soft carcass absorbs pavement breaks and "dots" without as much thunking and the dry grip is very good; better than I expected. I will have to wait till it rains to see about the wet.

I run a lot of negative camber and I can feel the tire initially push and then grip as you wind the steering in, the soft sidewall just takes longer to react and put the footprint on the ground. They don't feel as mushy as I expected though, just a little slower in transition.

I'll be at a test and tune this weekend and if time permits I'll run them around the course a few times and see what I think of them when pushed hard.

adam c

iTrader: (2)

Damon,

I would be interested to hear how they compare to your last set of tires ............ whatever they were, when they were new.

roadsterdoc

Good info. Thanks for posting. Looking fwd to more opinions. This tire seems to be a great bargain.

rynberg

Good info. I'd like to hear the comparison that adamc mentioned.

OC_

That’s a good tire for the money, great for eating at auto-x. There grip in the rain is amazing...

DamonB

More thoughts on the MX. I didn't get to run them during the test day because I already had 2 sets of race rubber to run and spent all my time working with those.

A lot of STS guys run the MX and to a man they all agree with me: The MX has good grip but its carcass is soft and so turns in and transitions slowly. You have to learn to literally turn the car in early as the tire takes a moment to "catch up" and actually turn in. The tire also gets better as it gets hotter. That's on the racetrack though.

On the street they ride softer than any other tire I have had but they do make some tread noise from the giant tread blocks; I notice the low humming when driving through town. It's possible this is worse on my car because I'm running more than 1.5* of negative camber and therefore more on the shoulder of the tire; I dunno. On the highway I don't hear more tire noise compared to what else I have had on this car as the humming is drowned out by wind noise around the cabin. Their dry traction is impressive; more than I expected and most I've had yet other than race tires. Still haven't got in the wet stuff yet and no I can't tell you how they compare to anything costing $150 a tire. I pay less than that for my competition rubber

Other tires I have had on this car:

Dunlop SP5000 (Really like them; highly under rated IMO)
Continental Contact Sport (Liked these as well but once worn halfway they really started to give up, especially in the wet)
Kumho Ecsta 712 (Absolutely hated them. No grip at all. They did appear to last well but I got rid of them quickly)

Race tires:
Yokohama RS008 II
BFG R1
Hoosier AS303
Kumho V700 Victoracer

1st to 3rd

I agree with what DamonB stated. I don’t have a lot of experience to pull from, but I have trashed on the MX’s through 4-5k street miles, an autocross, 5 track events, and 12 or so trips down the drag strip (pulled low 1.9's with 1.5* camber). They still have plenty of life left.
My only complaint about Kumho tires is they are a little too soft. That seems to be common across their entire line though (I've had everything from touring to their A/T's on a variety of vehicles).
They seem to have excellent hydroplane resistance. I'm a little mixed on the wet grip. Overall they stick very well, but they have stepped out unexpectedly on a few occasions. It just may have been the track/road, because it only happened a couple times.
Dry grip is exceptional and they are very predicable at the limit and after they break loose. Perhaps that’s a positive of the soft sidewalls.
Grip increases noticeably when warmed up and they have a fairly high tolerance to overheating. You have to pretty much overdrive them to get them greasy.
They get pretty hard around 40F and forget about traction around the freezing mark.
Overall assessment: I will be buying another set.
Damon, you liked the SP5000’s? I unloaded my 8000’s before they were worn out. They were turds compared to the MX’s.

Cheers!

Damon, what tire pressure are you running?

DamonB

The MX on the street I have 32 psi in them. With all the camber they feel better with a little extra pressure.

DamonB

Yeah, I liked them. Never been on the 8000 but the 5000 is supposedly a high performance tire with good wet and winter traction; it has sipes through the tread blocks and lots of void. They never felt squirmy, and had great dry drip all the way down to the wear bars.

Rated R1

I've been running these for about 2 years, and unless they start making Azenis in 225/50/16 or 245/45/16 I'll be buying them again.

DamonB

Rated R1, any comments on wear since you've had them a while?

Rated R1

They seem to be wearing just fine. They perform just as good now as they did new. I don't drive the car daily though.

DamonB

Just wanted to add that we have had torrential rain here in Dallas over the past few weeks and the MX tires have exceeded my expectations in the really bad wet stuff. I've been driving in literally inches of water and have yet to hydroplane. Overall wet grip is excellent as well.

Still very, very happy with these tires except for the slight drumming sound they make due to the large tread blocks at low city speeds.

reza

Kumho MX ? Very2 Bad.
A month ago on my way to autox, I got vibration at speed, turns out the rubber has separated, when we swap tires to Victos.
Lucky I got home okay.
I will post photos....

reza

2 tires with separations:

DamonB

Looks like those tires are worn way past the wear bar and are nearly to the carcass; should have been replaced long ago. Just because there is rubber left doesn't make the tire safe or usable.

The bottom pic especially looks like the tire was locked or overheated in that one area and so the rubber wore through. A street tire just can't survive with that little rubber on it. It will quickly overheat if pushed hard.

edv

I'm looking at the Kuhmos for a new set of SSR wheels I'm buying.
The only complaint I've found when researching this tire is that it can have a propensity to becoming out-of-round (when used on track, mostly). But this complaint was by one guy who went thru several of these tires suffering the same problem each time. Others never encountered the problem.

DamonB

I actually ran an autox event in the dry on the MX tires last weekend. Essentially it's what I expected as the grip was quite good but they transition very slowly. Slaloms just plain tested my patience because the tire is so slow to change direction; I had to steer very early. Anywhere else they felt great. It took me a while to adjust myself to street tires again and to get the pressures in the ball park; I had no idea where to start other than "high". I ended up at the end of the day with 45 psi in the fronts and 40 psi in the rears for autox work. I think I needed to go up a little more yet on the rears but the car felt much better than I expected. Once I learned how they liked to be driven I was going much faster than I expected.

I think for track use these tires would be a great choice as far as street tires go. They get better as they get hotter (opposite of most street tires) and they inspire good confidence. Turning into fast corners is just fine, it's only on things like slaloms where you are constantly weaving back and forth that I really didn't care for them. My tires are at nearly full tread depth though, I would expect that if they were shaved they would be better.

Carl Byck

I'll second Damons comments, I am running MXs on my Supra, 285-40-17, and 255-40-17. They are outperforming all other street tires I have tried, except the BFGKD at twice the price. They do not turn in like the BFG, but they wear twice as long, and are safe in the rain unlike the KDs. I see alot of them on high HP cars at HPDEs, everyone I talked to had positive comments. Reza, These are not race tires with the obligatory wear bar, they are street tires, and will be dangerously slick, and prone to failure once well past the wear bar per your photos. Peace, Carl

REFLUX

awesome, this only reinforces my previous conceptions of the MXs
they will definitly be my next set of tires after my Azenis wear out

KaiFD3S

iTrader: (37)

I am running them and I love them...but I still like my SO3's better....

reza

Yea..the Kumho MX are good.
The wear could go way past those in photos. I still use a pair on the front. The grip is still okay, but not in the rain, because the tread is no longer there.
The reason they look like that is in this picture below:

Tofuball

Interesting, would you say the drumming becomes unbearable for long highway trips?

DamonB

No. Every performance tire I have been on makes some tread noise and the MX is no exception. In my car the drumming is most noticeable around 40-45 mph. The noise is at just the right frequency at that point to be loudest. Many people may not notice it because I hear weird sounds come from cars all the time that other people don't notice The noise isn't bad enough for me to dislike the tire but it is something I notice.