Hydroplaning KM2s

[Hilldweller]

Well, today was a really bad pucker event. My KM2s have been on since April, a mere 10,000 miles. But I've had 4 butt-clenching hydroplane events in that time and today was the last straw.
I went over to Discount tire and explained what's been happening; they called BFG and Michelin will buy them back at about 50%. I ordered some Discoverer STTs.

I know some people who worship the KM2s; I'll never get another set.

EDIT: This is an interesting thread with plenty of insight but is irrelevant without looking at post #62. If you're looking for info on tires, don't miss that post.

 

[Corey]

What speed did this happen at?

My ******** Cepek Mountaincats are made in the same factory as the Cooper STTs from what I hear.
They are pretty similar.

Never had mine hydroplane on me in heavy rain on the freeway, but I do not go much over 62 MPH.

 

[The Adam Blaster]

How fast were you going and how deep was the water?

 

[Mr. Leary]

I noticed that they aren't nearly as good as my old Revos in the rain, but nothing to write home about... did they just start behaving that way after around 10k miles or have they been that was all along?

Mine have around 7k now, and this makes me worry about future performance.

 

[wrench-head]

Sorry to hear about your bad luck. I have the 37s on my rig and they have been great on a 6000lb tahoe, but there is a large 4x4 shop here that specializes in jeeps near me and they hate them. All the employees and customers installed them when they came out and almost everyone of them changed them out in the first fall with rain/snow mix. After the winter they all changed them out. Now all of those guys are running the new MTRs. I think that was since they are new, not necessarily any more thought than that. The few full size trucks running the MTRs have changed them out. Loud, pull to one side, and refuse to balance. Ahh the never ending debates...

I am a firm believer that the tire to vehicle weight is every bit as important as the tread pattern. If I owned a Jeep or other light vehicle I would not run them, much less any 12.50 wide tire, just not enough weight. I had the old MTRs on a LJ rubicon and they did good but were done at 18K.

-Alex

 

[sasaholic]

i have 35 12.5 15 km2's on my tacoma and so far the only problem i have with em is they chunk and cut easily, but im not in rocks that much usually. i have had em in snow and at 6 pounds i was basically unstopable. ive hit quite a few water patches and they never hydroplaned. actually it was quite the opposite when i hit the tires "dug" down nearly stopping my truck(no really, but really slowed it down" as they were looking for traction. for the price i got these tires for (660) there good, but i honesly will go back the the mickey thompson mtz's that ive ran and loved in the past.

 

[RusM]

Weird, during monsoon season (which will hopefully end next week!) I've hit some deep puddles:snorkel: on the freeway at anywhere between 67-74 (speedo's not so accurate anymore) and just rolled right through:smiley_drive:. 255/85's on a relatively heavy truck. But really, tires are like shoes, everyone's opinions and experiences are different.

 

[modelbuilder]

I thought MT's were pretty much expected to hydroplane more than normal AT tires.


.

 

[sasaholic]

I thought MT's were pretty much expected to hydroplane more than normal AT tires.


.

ya, but not nowhere near what hes describing, thats just plain unsafe

 

[modelbuilder]

ya, but not nowhere near what hes describing, thats just plain unsafe

Ya...but how fast was the truck moving, how deep was the water...etc. A lot factors go into this besides that fact that they hydroplaned.


.

 

[sasaholic]

very true. we havent hear much about the "how" yet

 

[Hilldweller]

How fast were you going and how deep was the water?

About 35 mph in a straight and relatively flat section of 45 mph zoned 2-lane; no standing water but it was raining hard.
I slid sideways toward a fire hydrant and got traction when I hit the grass, spun a little to the left, straightened, and kept going okay.
The MTR/kevlars never came unglued like that except on solid ice.

I thought MT's were pretty much expected to hydroplane more than normal AT tires.

The BFG rep told the Discount Tire manager that KM2s were not intended for highway use, just offroad.
Seriously.


These are 255/85-16s on a 2-door JK, loaded with my usual daily kit (about 250 pounds in back), bumpers, winch, 2.5" lift.
Each of the 4 scary events happened at less than 45 mph; the roads that I commute on are twisty 2-lanes with lots of elevation changes.

 

[DaveInDenver]

Interesting to hear. I still run the old KM tread that was known to be horrible, it's a slick as far as snow and rain are concerned. I had Discount sipe them and that helped a ton. However I thought the new KM2 tread solved that with the factory sipes molded in. They looked to me like an aggressive AT more than strict MT pattern. But at 35MPH I would not expect the KM2 to have been that bad at all. Wow. I've had my back end break loose more than occasionally, but I wonder if driving a pickup you just get used to that. I mean unless you are running chains or studded snows you are pretty much guaranteed to eventually find the wrong combo of speed, light load and road surface to get a white knuckle situation on a snow packed road.

BTW, I run 33x10.50x15 size and my truck is probably closer to yours in weight (about 5,000 lbs typically loaded) and wonder if the narrower width is making a difference. I ski on the order of 2 dozen times a season and so see easily 12 to 18 days of really wet, sloppy highways at fairly high speed. I put the siped old KM tires as about 70% of the standard BFG AT and unsiped KM tread at about 10% of the AT in hydroplaning. I only have to use 4WD if the road is actually hard snow packed and icy from the snow plows rather than just wet, melting snow. With unsiped MT KM treads I would have to pretty much 4WD on anything other than dry pavement. Even rain on roads that have been dry for a long time would be enough to slide. We get long stretches of weather without a good rain to wash the road, so when it does rain it's not just water, but oil and lots of contamination that make the roads slick. Not to mention the de-icer they use is a pre-snow sprayed liquid magnesium chloride that might be a good engine oil it's so slick on dry pavement.

The old MT tread was really, really bad on wet pavement. The AT is my only real comparison since BFG is the only company to have consistently bothered with the tall and narrow market for the most part.

 

[wrench-head]

Never would have expected them to be that bad either. Most of the jeep people here remvoved them due to fall/winter performance. In fact that one shop recommends against them for any jeep application now. I have yet to have any problems with mine and do almost all my onroad driving in 2WD through the winter. I had the old KMs on a 1 ton truck and they did fine for me as well. I guess I have just been lucky or heavy.

 

[DaveInDenver]

I guess I have just been lucky or heavy.

Betting location has a lot to do with it, too. Fact is Colorado is full of fun hogs who (a) drive pickups and Jeeps and (b) spend a lot of time in the mountains. So since weather-wise summer is the best weekend of the month in the Rockies, you're gonna be dealing with snow from Sept to July. Practice makes perfect, eh?