Decided to replace 25K mile stock RE040 tires 225/45-18. They were down to wear bands, and over three years old. Tired... NOT safe in the wet, and more slippery than owl snot in the dry (Please do NOT ask how I know for comparison. Really long story, with some endangered species thrown in for fun).

New Kumho Ecsta MX 245/40-18 tires installed this morning on stock rims with TPMS. These tires are wider than stock and beefier than stock. Much deeper tread than what was removed (duh). Since I purchased my car used, I don't have a good comparison against tread depth for OEM RE040s. Kumhos have 220 wear rating, RE040s have 140 wear rating. Both are Z rated, with AA traction and A temperature ratings.

Researched quite a bit before deciding to spend a large chunk of money. Since I autocross, I was willing to give up some road comfort for some better traction. For comparison, the Kumhos are still about $60 per tire cheaper than the RE040s. I could have saved even more money by going with the Kumho Ecsta SPT, but decided to get a lower tread life rating and more noise, for better traction in the dry.

First impression - Compared to old, tired, dried out stock tires? Not much comparison. Smoother rolling, less road imperfections are felt. Seem to turn in as well as the RE040s that came off. Not sure about control at the limit yet. These tires produce a 'thrum' with light buzz-type vibration felt through steering wheel at approx 58mph, but are still quieter than RE040s. Have not had them above that speed yet. Should have some more high-speed impressions this evening. I have some traveling to do.

Purchased from Tire Rack via the internet. Recieved next day (northern FL delivery, Tire Rack is in Georgia, I believe). Drop-shipped to Tire Kingdom for install. Total price as delivered, including road hazard insurance and freight, was approx $770.

Installed by Tire Kingdom (TK Performance) in Jacksonville. Good job, they were busy, and tire machine broke when handling my last rim. No damage to rim (whew). Balanced correctly. Total cost for mounting, balancing, etc (including fee for handling rims with TPMS) was approx $90.

No rubbing problems, even though they seem significantly wider. Diameter is within 1/2" larger than worn-out stock tires. I would guess that when comparing to new, with no wear, these would be almost exactly the same diameter as stock size.

Will break them in for a couple hundred miles before next weekend. First autocross on new tires will be next Sunday. Will report back afterwards.

Here are some before and after pictures. Sorry for the different angles and light quality. Best is picture of the front with the new tires.

 

Grats on the MX's, these tires rock! Here's a pic of mine:

 

You'll find that they are much better auto-x tires than the stockers. They are very light in any size which is good for unsprung weight. However as a result of the low weight they haven't done as much as possible with sidewall reinfocement so your going to have to play around with your tire pressures to find a happy balance between low front end grip due to too high of a pressure and low front end grip because of too low of a pressure resulting in the sidewalls rolling over.

Take this next bit with a grain of salt as I've only seen cars driven very well with this tire but never driven one myself. I and I assume others would reccomend the Hankook Ventus R-S2 Z212 as a much better tire from an overall aspect.
They cost less then the MX and the life of the tire is similar, and they just released 18'' sizes.

http://www.hankooktireusa.com/produc...ail.asp?pid=13

 

I had MX's on my mazda3, sticky but NOISY

 

nice tires and pics!

 

The MX's rock, but you should have picked the street version ESTCA

 

^^ I was going to pick the street version SPT tires, but wanted something one more step stickier to do dual duty for street and for autocrossing.

And I do think they ARE noisier than new RE040s, especially around 45-60mph, but at highway speeds above 65 they seem to find their place and quiet down a bit.

Now have approx 80 miles on them. Will put another 120 or so on today.

So far, they do seem to have the same turn-in reactions as the Bridgestones, and the softer sidewall (not run-flats) makes for a more comfortable street-ride. Not getting whacked by crosswalk decals and small road imperfections.

 

I would think the SPT's have better grip since they are a 3+ year newer design than the MX. I ran the MX on my BMW M3 before and I liked them though. I didn't know that the RE040's were runflats although the sidewall does seem pretty stiff to me. I just went with a second set of track wheels with falkens will probably replace the RE040's with the SPTs soon.

 

Newer doesn't necessarily have anything to do with the tire's intended purpose. Bridgestone 750 is a lot newer tire than the S02, but the latter destroys the former in dry grip.

My experience with SPTs (not on my 8) is that they're not an ultimate performer in dry weather. Not even close. And unless one lives in the tropics and has to drive through rain every day dry weather tire grip is what should matter most for a sports or high performance car.