Skip

What. The hell. Did I do.
December 15, 2012 1:51 PM   Subscribe

Driving home this afternoon, I spun my car 360 degrees. I have no idea what happened. Please help me figure out what it was so that it never, ever, dear god ever happens again.

I had just dropped a friend off at the airport. I was driving around a slight curve, accelerating gently, and going 38mph. I know this because I checked my speed before shifting; for whatever reason, the less-than-conscious part of my brain that governs shifting thought I was in second and needed to get to third, when I was, in fact, in fourth (I must have seen my gear stick out of the corner of my eye). I shifted into third and hadn't yet pulled my foot off the clutch when I heard the engine rev slightly and I realized I was in the wrong gear. I rapidly put the car into fourth and that's when I felt a slight jerk and then I was spinning. I was already steering into the skid so I just waited the spin out, and the car stopped at nearly a full 360 degree turn.

There are no factors in this scenario I haven't driven in and through a million times before. Some factors must have doubled or tripled up, but this is beyond my expertise.

Other factors: the road was damp but not wet - it wasn't raining so much as mildly sprinkling (I had my wipers on the lowest setting and even that was a bit much). It's decidedly above freezing here (Siri said 48, now that I'm home my local weather says 52), so no black ice. My car is a standard transmission (obviously), the car is in overall good condition, and my tires are a little more than a year old. Nothing is wrong with the road where I lost control. I've driven this spot countless times; it's a very normal, gentle curve - much like an entrance/exit ramp designed for ca. 40mph traffic. I've also, like every manual driver, hit the wrong gear many times and never had any issue other than excessive or insufficient revving. I pulled over afterward to calm down, and also checked all four tires while doing so; I could see no outward sign that anything had happened or would cause anything to happen.

Can someone tell me what happened, or may have happened, so I can ensure this never happens again? I'm thoroughly freaked out, partially from very nearly being in a bad accident, but more so because I don't know what happened and can't be sure it won't happen again. Also, my car is about 18,000 miles before its next service, but I'm happy to take it to my mechanic now, especially considering I've got a 12 hour drive coming up for the holidays.

Sweet baby jesus.
posted by AthenaPolias to Travel & Transportation (24 answers total) 3 users marked this as a favorite
 
Sometimes when it rains, it causes accumulated oil on the road to rise up and become slick. So although no black ice, perhaps it was still slippery. This can especially happen if it has not rained in awhile, so there is more buildup on the road than usual.
posted by SpacemanStix at 1:57 PM on December 15, 2012 [3 favorites]


You might have it the only spot of black ice on the otherwise above-freezing road. This happened to me - on a nice day, I was suddenly in the ditch across the road and pointed back the way I had come. Or your car may have a sense of humor and was trying to teach you a lesson about that wrong gear choosing thing.
posted by Cranberry at 1:59 PM on December 15, 2012


If it was the first 15 minutes or so of rain, that's a contributing factor. Apparently that's when the issue with oil in the asphalt is worst. See wet pavements here in the Pennsylvania driver's manual.
posted by Monsieur Caution at 2:01 PM on December 15, 2012


Classic oversteer error caused by an upset to fore-aft weight distribution.

Your initial condition was gentle acceleration, i.e. the car's weight was rear-biased. This would result in a degree of understeer, due to less grip at the front tires (which turn the car) and more at the rear.

When you messed up your gear shifts (twice!), not only did you stop accelerating, but you inadvertently threw in a bit of engine braking when the clutch engaged, transferring the weight to the front of the car. The front tires hooked up and suddenly provided more grip, while the rear tires lost grip. End result: your car swapped ends.

Moral of the story: no sudden moves (gear changes, aggressive gas or brake) while you're in a turn.
posted by wutangclan at 2:03 PM on December 15, 2012 [28 favorites]


I've done this, both accidentally on a racetrack and intentionally on a skid pad.

Is the car rear wheel drive or front wheel drive? What tires do you have?

You unsettled the car by lifting throttle during a turn, and the wheels broke traction. Probably compounded by rain.
posted by joshu at 2:04 PM on December 15, 2012


What wutangclan said. Also, steering into/out of skids - the semantics of the rule are confusing, and it sounds like you had the wheels turned in the direction that the road was curving and kept them turned in that same direction for the duration of the skid. In the future, you want to steer (gently!) in the opposite direction that the front end of the car is moving. I once hit a patch of black ice going around a curve on a highway and proper steering is what saved me from spinning and possibly rolling my car at 60 miles an hour.
posted by keep it under cover at 2:05 PM on December 15, 2012 [2 favorites]


I will bet with 99.9% surety this was the result of your tire's conditions causing hydroplaning.

1. What are the conditions of your tires, inc thread wear?
2. Are your tires from a cheap/stock pep boys type brand?
posted by Kruger5 at 2:12 PM on December 15, 2012


Joshu, it's a front-wheel drive car, and as for what particular tires I can't say, but I live in an area that doesn't get much snow (even less in the past two years than normal, i.e. none) so they're all-weather. I do recall asking for the better of the three brands offered to me when I last had them replaced.

keep it - you nailed it. In the spin, I was trying to sort out which direction my tires needed to be in, and all I could figure in those few seconds was that there was the potential that turning my tires in the opposite direction could flip me, so I stayed the course. I was also wondering if I was going to flip regardless of any action at that point, though, so I had a fair number of worries to grapple with. I'm a little more self-possessed driving in snow and have done this correctly in the past, but I was caught unaware today.

wutangclan, joshu, keep it under cover - got it. Wow. I had no idea those things could come together in such a dramatic fashion. Lesson very much learned. Thanks.
posted by AthenaPolias at 2:14 PM on December 15, 2012


BTW, the correct reaction when this happens is:

1) Opposite steering lock to correct the spin direction.
2) Gas, and lots of it, to regain rear traction by shifting weight to the rear again.

But you will certainly mess this up unless you have practiced it a lot at the race track (and gone through many sets of tires). Controlled oversteer is very hard to do correctly, especially in a street car that hasn't been set up for it. This is exactly what all those drifting, burnout, gymkhana, etc. videos you've seen are demonstrating.

For the average driver, avoid getting into this in the first place by driving a well-maintained car gently (especially in turns).
posted by wutangclan at 2:19 PM on December 15, 2012


Steer into the skid, hold the throttle where it was - do NOT 'gas, and lots of it', and wait for the car to stop sliding, then when the tyres are gripping at both ends steer as normal.

Hard acceleration will only make matters worse.

These things happen, black ice, slick roads after a long dry spell, or (as has happened to me) spilt diesel fuel. You are not in control, so don't expect the car to respond immediately, you do the right things, and wait for the car to slow enough to regain grip, or to pass through the problem area. Hydroplaning is a bit different, but treated the same way.
posted by GeeEmm at 2:32 PM on December 15, 2012


But you will certainly mess this up unless you have practiced it a lot at the race track (and gone through many sets of tires).

A snowy parking lot will work, too. Make sure it's empty and safe, of course, but a little practice goes a long way.
posted by Pogo_Fuzzybutt at 2:32 PM on December 15, 2012


wutangclan, as it's a front wheel drive, i'm not sure that's the right thing to do, since it's front wheel drive.
posted by joshu at 2:33 PM on December 15, 2012


as it's a front wheel drive, i'm not sure that's the right thing to do

Oh yeah, my bad. Scratch that.
posted by wutangclan at 2:34 PM on December 15, 2012


You may be interested to know that all 2012 models sold in North America are required to have ESC, which should help prevent this kind of thing.
posted by modernnomad at 2:46 PM on December 15, 2012


It's not inconceivable that another car spilled a little oil (gas, diesel, whatever) on the road. With damp asphalt, it would be harder to see on the road and would tend to spread out more.
posted by Daddy-O at 2:46 PM on December 15, 2012


The single question I missed on my first license exam was "When is the road most slick?" and I had picked "During a rainstorm" instead of the correct "As it just begins raining."
posted by odinsdream at 2:54 PM on December 15, 2012


The physics of it are this: the car wants to go in a straight line. Even on a gentle curve at a moderate speed, there is significant force on the tires to stop the rear from coming out from under you. The rear of the car wants to keep going straight (from its perspective) while the front of the car is pulling it around the turn.

So what happened is that when you put it into third, you put a lot of engine braking onto just the front wheels. The front of the car was trying to stop while the rear of the car was trying to keep going. If you are going straight, that would be fine, since the front of the car will stop the rear of the car. But since you were in a curve, the rear of the car was not completely stopped from moving and swung around.

In other words, the momentum of the car was pointing out your side window. When your traction broke free, that momentum was no longer being constrained and your car tried going in the direction the momentum was pointing. The front wheels had more traction than the rear wheels at that instant, so the rear of the car swung around an axis created by the front wheels.

This happened to me once, and it is heart stopping to realize how much actual energy is in your vehicle. I was going like 10 mph, and someone hit my very rear bumper going like 5 mph. I spun around almost 180 degrees.
posted by gjc at 3:49 PM on December 15, 2012 [3 favorites]


For the record, gjc has the physics half right. When cornering, ALL the car (not just the front, not just the rear, but all of the car) wants to go straight ahead. The tyres, or more accurately, the interaction of the tyres with the road through the bit of rubber in contact with the road, force the car to turn (or stop, or accelerate).

When turning, either end can slide (rear slide = oversteer; front slide = understeer) regardless of where the engine is, or where the driven wheels are, and while you can do things to speed the process, and/or minimise the chance of an accident, basically you are waiting for the car to slow enough for the tyres to regain their grip. When that happens, you can get things back to normal with brakes, steering etc that work as you are used to.
posted by GeeEmm at 4:45 AM on December 16, 2012


You might want to the about taking an evasive driving course. I took one many years ago and it has saved me from a few accidents. Plus, it is also really fun to spin out on a skid pad.
posted by kamikazegopher at 8:52 AM on December 16, 2012


Oooh absolutely seconding the suggestion for taking a defensive driving course. These are tons of fun! My dad and I took one back when I was in high school, and aside from the fun of being literally the only two people who weren't attending due to court order (and therefore having a blast whilst everyone else moped), it was full of awesome activities like getting to drive a car that had hydraulics mounted on each wheel which allowed the trainer to reduce friction on any combination of the wheels to simulate all kinds of slide conditions. Fantastic fun, and really helpful in getting a feel for situations you won't otherwise encounter until it's far too late to know what to do.
posted by odinsdream at 10:27 AM on December 16, 2012


Adding my voice to greasy roads (rather than wet ones) being much more problematic in terms of grip. Also, the wrong gear selection did cause the spin. It is likely, however, that you were much nearer the edge of grip than you realised. That, to me, is much more the issue. A sharp deceleration like partially selecting the wrong gear shouldn't have had enough energy to spin the car 360, even with the wrong steering input. Consider that you may have a little more confidence in your cars grip in adverse conditions than is warranted.

The gear shift issue (inattentive driving) will have caused the spin (differential braking of front wheels only, combined with relatively high loaded turn) but it should have been easily quelled by just lifting off the throttle and easing off the throttle (even just pointing the wheels straight ahead should have done it). The fact that it didn't meant speed was also a factor. You had a very very cheap lesson there and I urge you to listen to it closely. If the tyres have good tread and are not more than 5 years old (as you mention), I think there is likely nothing wrong with the car.

I was already steering into the skid so I just waited the spin out, and the car stopped at nearly a full 360 degree turn.

This is the main issue with oversteer - people do have very genuine difficulty understanding what people mean when they say 'steer into the skid'. Driving eduction on this is pretty poor, to be honest. It's only instinctive if you are are an instinctive driver anyway.

On one hand, it's completely logical to anyone that has a really slow oversteer (where the car turns more than you wanted it to, like in this example) to steer the other way - ie cancel out the extra turning that just happened. The car turns more right than you want? Well just turn left a bit. But often the oversteer is so shocking and surprising that instinct is stopped and people say to themselves "Steer into it? Well 'in' is in the direction.... and so the over thinking starts and people usually think wrong because they are flustered. It's really a muscle memory thing you need to train into yourself and the suggestions for a skid school are something you should very much consider. Well worth spending the money on it because the next 360 degree spin may have a tree somewhere in its arc...

Of just as much importance and potential problems is the issue of over-correcting - even if you steer the the right way, steering too much (or too late/slowly) will just result in a spin the other way. It's too tempting to keep winding the steering on until something happens, but usually if you do that, you end up with a turn and a half of steering lock on and the car will snap back into a spin the other way. Usually, a fast and sudden correction of about 3/4 turn of opposite lock from where you are (ie turning left while in a right hand turn) will be enough. Get the steering lock on and hold it and wait. This is not at all an easy skill to master so, again, get yourself to a skid school.
posted by Brockles at 11:27 AM on December 16, 2012


A snowy parking lot will work, too [for practising threshold manoevres]

Not really. While it's a lot of fun, the lack of traction means that it's impossible to get any significant weight-transfer happening. Thus whatever you learn on snow, while useful for driving on snow, is not as applicable to bare-road driving.

[The defensive driving school] was full of awesome activities like getting to drive a car that had hydraulics mounted on each wheel which allowed the trainer to reduce friction on any combination of the wheels to simulate all kinds of slide conditions.

Similar problem to driving on snow. A) It's dynamic balance transfer that you must learn to deal with, not a static imbalance. B) These skid rigs reduce friction to such a degree that the lessons learned are not as applicable to the real world. C) Reacting immediately, instinctively and correctly is essential -- you won't hone these reflexes if everything is slowed down with snow, ice or a skid rig. Many high-performance driving schools have stopped these practices precisely because they don't really work.

The best defensive / high-performance driving courses are the ones that let you use YOUR car (the one that you drive every day) and run drills using nothing more than cones, a skidpad or a dedicated track.
posted by wutangclan at 11:47 AM on December 16, 2012


A) It's dynamic balance transfer that you must learn to deal with, not a static imbalance.

You don't need to replicate the load transfer characteristics to teach control of the consequences, though. Not at all. It is many times harder to teach someone the car control and understanding to get their head around weight transfer than it is to get them to understand and mitigate oversteer and understeer enough to make them safer.

B) These skid rigs reduce friction to such a degree that the lessons learned are not as applicable to the real world.

Disagree. With a skilled operator you can very accurately model loss of grip to get the driver to feel and learn to cope with the resulting behaviour (ie someone sitting alongside you who doesn't just take all the weight off the wheels as their grip failure case). They're designed to model grip loss, not weight transfer mechanics, though.

As such, skid schools have their place. They are a first port of call level of understanding a car that loses grip and are really good for low skilled drivers to experience and appreciate the sensations and results of different styes of grip loss. They are not, however, something suitable for a high performance driving school. They should have been completed (or understood) before you get to a high performance driving school, as HPD is a step further on than normal skid school skills.
posted by Brockles at 2:12 PM on December 16, 2012


I would argue that this wouldn't have happened if the road conditions were dry. You note that you were going under 40 MPH, which is generally much too slow to get a car to loose complete traction/spin. As others have discussed- you prompted the spin by upsetting your car in the turn, so remember that even a gentle turn represents a great deal of change in inertia, and even a small amount of water can introduce significant traction loss.

Another significant factor in traction control is a bad tire setup - you mentioned yours are only a year old and should have good tread, but they could be very badly aligned. Bad alignment, which is the toe and camber (and caster but nevermind that one) of the wheel, dictates the angles that the wheel sits on the ground. If the wheels are misaligned, especially the front ones, you will have much less traction. The tire shop you got your wheels at can check this - and be certain to mention what happened.

All season tires are not as well designed for wet conditions as summer tires (or dedicated wet tires) so this will also be a factor, as will the width of the tire - in this case narrow is much better. All season and summer tires generally get hard at cooler temperatures - hard tires give you less traction. You can check your tire's hardness by looking up your treadwear rating- the a three-digit number on the sidewall that ranges between 0 (soft race tire) and 700 (semi tire). Higher number means a harder tire, and those fuel saver tires can have a really high rating - in the 6oo's.

So to prevent this in the future - get your alignment checked, pick narrow seasonally appropriate tires, or go all out and get hydra tires and drive slowly through wet corners.
posted by zenon at 9:16 AM on December 18, 2012


« Older Musicfilter//: I love the fol...   |  In the State of Indiana, is it... Newer »
This thread is closed to new comments.


Post