How can you know if this will happen again

I have used Kumho tires since about 2006 and have been quite happy with them. Friday I replaced the front tires with Kumho Ecsta 4X tires, rear still have the Kumho Ecsta ASX tires I put on last year. I had been using the ASX tires before, but tire rack had better reviews for the 4X tires. Seems like I get 2 years out of a pair. Anyway I drove about 400 miles over the weekend, everything feels great. I purchased a lifetime alignment from Sullivan tire last year so I can get an alignment every time I get a pair of tires, so also got an alignment.

Today I am driving home and am on the fellsway in Saugus (for those familiar with the area) and crossing up and over Rt1 to get on RT1 North. Coming down the other side the rode makes a bit of an S curve. It had been raining today and when I started into the first turn at approx 35MPH (or less, heavy traffic) I went into a spin and just whipped around into a 360, and stopped almost right in line with my travel path. It was like I hit ice, I am still vague as to which tire lost it first, but I was hitting the left curve of the S turn first so assuming right front or rear would be viable. I drove the rest of the onramp and immediately into a gas station there to asses things. I found nothing really except what could have been oil reside on the right rear tire and also the fender area behind it, I wiped it with a paper towel and also the tire, seemed like a lot more of something there as compared to the other 3 tires. Also the roadways are still quite wet from heavy afternoon rains.

My questions: (I have only ever spun a car once before and that was black ice for sure). Can I spin like that just from a wet road at 35 MPH? Are the tires likely crappy tires and that bad on wet surfaces?

Thanks,
Eric

and took a right hand corner ( north bound Saratoga Ave. to east bound Stevens Creek, in San Jose, CA) and the back of the truck came around and I ended up looking over my right shoulder through the rear window to see where I was going. The truck did a 180 and not a 360. Took my foot off the gas and the truck came to a stop before any tires kissed the curb.

BTW, I was not driving fast either: the road was wet; not soaking but wet.

Sincerely,

MarcW.

My guess is that the different grip characteristics between front and rear axles caused or contributed to this spin. I have no experience with either of these tires but running different tires is not a good idea.

Does your car have PSM? Was it on when you spun?

I have spun twice. Both times with PSM off, once when it was 35 degrees F and I was running summer tires and turned PSM off on purpose to get some fun oversteer, I was going less than 30mph but power on ... the car came around so fast it was scary. Very dumb mistake to push those tires in the cold and I was lucky to have no damage. The second spin was during an autocross . I run with PSM off during autocross so I can learn. I entered a turn too fast and lifted the throttle too suddenly and experienced "lift throttle oversteer". The car came around really fast, this time it was in a safe environment however and I learned from it. With the engine and mass in the middle of the car, Boxsters handle great, but they will spin, and when they do they can spin like a top.

Quote
newt
My guess is that the different grip characteristics between front and rear axles caused or contributed to this spin. I have no experience with either of these tires but running different tires is not a good idea.

fallacy.

the tires that were on my car when it came from the factory were VERY different; 205 in front and 255 in back, you can't get much more difference than that.

in countries like germany and switzerland where you can't even put different wheels on a car without them being homologated by the authorities, it is legal to have different brands, tread depths, and sizes front to back and it is very illegal to have ANY difference from left to right on the same axle. if you get a flat and your tire has more than (IIRC) 20-30% wear then you are obligated to buy two new tires so they match. it is illegal for any tire dealer to sell and mount a tire on an axle where the other tire is worn.

it is simple physics, a difference in grip from left to right will destabilize a car. front to back may not be optimal with different tires but the car remains predictable and thus safe.

--
MY 2000 S, Ocean Blue, Metropol Blue, Savanah Beige.
Bought June 2000 - Sold May 2010

That's a good point about the 205s being very different from the 255s regarding grip. I have just always heard that you shouldn't mix tires on the car and I believe it is not recommended.

I think different tires means tires of different brands and handling characteristics.

The front and back tires on Boxsters and 911 are different in width, but need to have the same handling characterists. If you have tires with more grip at the front than at the back, corning and or braking become very dangerous.

An extreme example would be having a front wheel drive car with snow tires on the front only. That works great when you want to get moving, but slam on the brakes and those rear summer tires are going to want to get right out there ahead of the front snows. Same type of thing will happen in a corner.

Guenter
2014 Boxster S
GT Silver, 6 Speed Manual, Bi-Xenons, Sports Suspension (lowers car 20mm), Porsche Sports Exhaust, Porsche Torque Vectoring, Auto Climate control, heated and vented seats, 20" Carrera S Wheels, Pedro's TechNoWind, Sport Design steering wheel, Roll bars in GT Silver
[www.cyberdesignconcepts.com]

and there was heavy traffic, why didn't the other cars spin? Just wondering.

I thought about that and also thought maybe I drove through some oil before that and it was at that spot the conditions were such that I slipped.

Aside from minimizing oversteer, etc, water evacuation became more of an issue. Ultimately, two different tread patterns and/or compounds could be used, and as a practical, manufacturing concern, possibly using two brands. I'm confident the folks at Weissach can work this out.

The differences are in general small. Much smaller in fact than the differences in staggered width setups, and vastly less than road surface variations and weight transfer (friction =force * Cf, but of course, tires don't obey only friction, but that's a logn story best told by Prof Lewin....). It was likely the road surface, and next in line, weight tranfer. Might tires contribute? Sure. They might contribute to or resist the spin. Please provide detailed vector analysis on whcih it is, because that's beynd my pay grade!

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

has to be a big question. If there was a spot of oil just in the wrong place that's one thing.

I think if I were in your shoes I'd find a big empty parking lot on a rainy day and see if your car contiues this behavior. If it does, the tire setup has to be questioned. If it doesn't, I'd think the oil was to blame.

Maybe you should move to the south shore!

The road surface may have been contaminated with the rain spreading it over a larger area.

First, its not your tires. Despite the fun we haev debating variosu tires, they are all +/- 35% of each other; yours were all-seasons (good in wet) and you were going 35 mph *with traffic* whcih means way under normal limits. I am 99% positive it was the road surface- whcih can be vary incredibly with conditions. Its oen reason speed limits are arbitrary adn worth ignoring. Int he dry thety are universally low. Int eh wet and snow they are universally high. They are never correct.

Its easy to spin a car, given the right circumstances. Its VERY easy to spin a boxster once it gets going too. I'll ntoe its also very easy to catch, btu you must be quick and decisive. That's rare. The boxster is mid-engine. So it has little mass at either end - that's great when you wish to turn - very little mass opposes your tires' wish. On the other hand, very little opposes a spin. It can accelerate (rotationally, not linearly) very qucikly. And yours did.

I would pretty much promise that you spun due to a wet road, whcih the wet brought oil to the surface. That can be very slick - maybe 25% the traction of a dry road. That's not a meaningful number, just to illustrate the magnitude of the possible difference. Its even worse if the road is mostly godio adhesion, btu one tire hits a spot of oil. Now you have traction on one side pulliong the car back, adn not the other side. Just like a differential-tracked buklldozer, that's the recipe for turning. Sometimes quickly. Voila.

I'll also bet you went off throttle or touched the brakes in the turn too. Most people do. That transfers weight off the rear, adn it lets go even sooner. Its nto necessarily a fault, i dont advice rear-ending the taffic in front of you jsut to keep ideal weight distribution!

Its really a lesson that:

1 wet roads are treacherous
2 boxsters spin quickly due to centrally located mass
3 weight transfer is meaningful

Glad you and the car appear to be no worse for the wear. btu i bet you didnt go into the station to assess. Mroe likely for a change of garments :-)

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

and once just to see what had happened I went back and ran the same line at the same speed and sure enough I spun just like the first time. One corner the front end just slid, in the other the rear spun around.

In both situations it had just started to rain and curves are where a car will deposit any dripping oil and if it has been dry for a while, oil from many cars accumulates and when wet, disperses and you feel like you just hit a load of ball bearings. It isn't water dispersion grooves that help you as the "rubber" is sliding on the oil slick.

I know a number of people running those tires on their BMW's with similar results. Spinning out in the rain was one of the big complaints. It's why I went with the Kuhmo LX Plats for our city beater(318ia), but the tires are not as performance oriented as I would like. Definitely a decent tire for the $ though, especially if your running a separate set of winters. If you want all seasons, you might consider the Conti DWS. We've had them on the 986 for over a year now and love them. They seem unaffected by big temp swings or drops.
regards

Interesting stuff guys, thanks for all the replies and conversation. I am convinced it was the road and not my driving. and no Grant I wasn't changing garments , I honestly was assessing the damage. My girlfriend was pleased at my calmness and the fact that I was able to maintain control and keep us in the road. She even commented most people wouldn't have reacted as quickly as I did. While this was a bit unnerving, I knew I wasn't in danger so I really just pulled out of the spin and kept going as I knew the station was only a few hundred yards away and I didn't want to snarl traffic knowing we were ok and I never hit anything so the car felt fine.

That being said, as I mentioned I got the new tires Friday. I previously had mixed Kumhos on before without issue, just not this new model (at least new to me). I was mostly asking if oil on 1 tire could really induce a spin like this, and based on all this feedback I believe that to be so. I hadn't thought about the weight in the middle and how that would allow the spin to really grab hold, but it makes sense.

Noone was hurt, car is fine and all in all I feel better understanding this stuff. Rain again today and drove the exact same route, I was a bit nervous hitting the same turn, but felt firmly planted all the way through. I do plan to hit a parking lot on a rainy day and exercising the tires.

Cheers!
Eric

In fact, that is exactly how anti-spin technology - for example PSM ("please save me") works. It applies some combination of braking to different wheels to counter a spin(like driving a bulldozer, sorta). Your experienced the reverse.

very very possible.

now if the other 3 had excess grip, then no, it should not likely cause them to lose traction. But the reality is probably messy - nothing had a ton of grip, weight distribution changes, one tire loses it all, back end is now reliant on one tire, on water, to keep it from starting to slide, centrifugal force overcomes mediocre traction, and the rest is history.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Tires frequently are extra slippery for the first few hundred miles and you are advised to drive extra carefully until they have worn off the "factory finish" on the tread. So that may have had something to do with it.

1. could very well have contributed
2. but still, overall, differences in tires pale compared to differences in road conditions

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

I did some surfing and saw a lot of discussions, a couple having posts that seemed credible, wherein the writer claimed to be quoting a representative from Pirelli or Dunlop. It's possible that nowadays Teflon or similar coatings are on the molds themselves, and don't transfer to the tires.
Also, it's possible that a new tire requires a few heat cycles to finish curing.



Edited 1 time(s). Last edit at 05/15/2012 09:31PM by Laz. (view changes)

Too much water, a bit much on the throttle, but at the time it came as a complete surprise.
And I thought that I was going to recover right up until it stopped.

Fun starts at 15 secs.