i live in PA, and we just had this ice storm last night and the roads here were bad, we had a 2 hour delay for school. so i got ready and left. no more than 30 sec after leaving my house, i went down this hill and just felt my car fishtailing. i was going around 10mph too. the back end spun, my front tires went over this curb and i ended up doing a 180 down the whole hill. this other just watched me and drove past. i got out immediately to check for damage but saw nothing out of place. it kinda freaked me out, thats the first time i ever lost control of my car. but now my dad wants to get me snow tires for my car. BTW i was using the stock 16' rims.

any suggestions on good tires for snow?

 

i suggest u get your allignment checked out. it could have possibly bent a control arm or over stressed a cv boot and cracked it.. just to be cautious i'de get it checked out if you dont' know how to do it yourself.

 

Glad to hear you didn't get hurt... get your car checked.

 

Ya.. spinning out is a scary thing.. I would imagine especially downhill...

Did you by any chance step on the brakes before spinning out? Do you have traction control (not like it would've helped much in your situation), but still...

 

If your sliding was indeed caused by ICE and not SNOW, the addition of snow tires (unless studded) will be of little assistance. (not sure if studded tires are still legal in PA, there were when I last drove there, but that was 1974).

 

Glad that you are ok and nothing major happened to your car. But do get it checked out just to make sure.

 

Nokkian Hakka 10's are the best! Look for them, they are sometimes harder to find, but come highly recommended!

 

thanks for all your concerns guys. when i noticed the car starting to fishtail i turned my steering wheel into the turn. and i did hit the brakes right away then turned my steering wheel to the right. i think i ended up pumping the brakes then when i started to turn around. i dont know if that was the right thing to do, but it happens fast and i didnt have time to think. im just glad that when the car that was driving towards me, saw that i lost control, they stopped where they were, otherwise i wouldve definetly hit them.

 

My drivers ed book claims that you should turn your steering wheel out of the skid (ie. in the opposite direction that your skidding/spinning). I don't know, because the few times that I've skidded, it happens so fast, and you feel ABSOLUTELY no control over the car.. [no skids in my maxima yet, (THANKFULLY)..!!!

Even tho it depends on the exact situation, I have been led to believe that sometimes slamming on the brakes right away could worsen the condition. Nevertheless, important thing is that you and your car made it out alive!!

 

All 5thgen maxes have ABS so you shouldn't need to pump your brakes right? You should still be gentle as hard stopping causes weight shift. What about once you are in a spin, foot on or off the brakes?

 

Well ABS is just there so that your tires don't lock up, and you don't skid in the first place... When your traveling in a straight line, and you have to stop fast, first make sure that there's nobody tailgating you, and then slam on the brakes as hard as you can [the abs actually works rather well, and has saved my *** several times] Major advantage of ABS is that you can continue to steer the vehicle even while braking at a max!!!

Once your in a skid/spin, it's mostly intuition that would get you out of it. [Besides, he was on ice]

I would tend to think that pressing and releasing the brake at certain points, and clever turning of the wheel during the skid might help you, wheras ABS alone applies almost uniform braking, which is hopefully relatively even to all of the tires. {therefore having little net effect on your actual spin!!!} [If in fact, one tire brakes harder than the others, your more prone to a full spinout!!]. So basically, what I'm trying to get at here, is that every situation is unique, and most of us have 20/20 hindsight.... After the incident we know EXACTLY what we SHOULD have done!!!, but by then, it's often too late!!

Drive carefully!!!

 

Yeah, I went up to the snow this weekend and I took the opportunity to test the ABS system. It's rather noisy clackity clak. Kinda cool to see what it actually does. Of course I was going straight when I stomped on the brakes so no spinning action.

 

It works just as well on dry road !!! In fact, you should try it out in an empty parking lot somewhere, because it's sorta counter-intuitive if you've never driven a vehicle with it before!!! [pumping the brakes is an addictive habbit many carry over from older vehicles!!]

Your supposed to hear it.... It's supposed to make noise.. It's a feature :-)!!!

 

I'm on the same boat as you living in pa. I bought a set of Michelin Arctic Aplin for the winter for $350 at a local shop. Fitted with steel wheels for the winter. Although I haven't use them, my buddy from upstate recommed them to me. He said they are the best, right next to the Bridgestone Blizzak. hope that helps

 

I replaced the stock 17" tires and rims with 16"
steel wheels and 225R55-16 Toyo Observe Garit. These
are H rated snow tires that are amazing on ice and
snow. This package was assembled by my local Nissan
dealer.

 

Once you go into a spin, take your foot off the brake. Your car cannot reagin any directional traction if the brakes are on and the wheels are locked up. Once you are traveling in a straight line, you can attempt to brake again.

Regaining control in a skid on ice can be tricky, since almost anything you do can create a new problem. I have had the best results by taking my foot off the brake, shifting the car into neutral, and attempting to steer out of the spin. You need both hands on the wheel (as opposed to one on you shifter), since it is quite easy to reverse the spin and send the car spinning in the other direction, and then needing to reverse the direction of you front wheels again.

I just put my Blizzaks on last week, and so far they seem great. However, I doubt any tire will help much one you're into a spin, they just improve traction and lessen your chances of losing control in the first place.

 

---------------------------------
Agree with you. I have also been looking at a set of winter tires for my 2K SE. Even though I live in NJ and winter weather isn't very severe here, it only takes one storm and one mishap to scrap your Max! Tire Rack has some good info on winter tire tests, and also recommends tires for the Max. Personally I am looking to get Pirelli SnowSport or Winter 210s over the Blizzaks or Alpins fitted in 16" wheels versus my stock 17". It is silly to get winter tires on 17" low profile tires, it defeats their snow/slush plowing capabilities.

Just more thoughts into this topic.

 

<<i live in PA, and we just had this ice storm last night and the roads here were bad, we had a 2 hour delay for school. so i got ready and left. no more than 30 sec after leaving my house, i went down this hill and just felt my car fishtailing. i was going around 10mph too. the back end spun, my front tires went over this curb and i ended up doing a 180 down the whole hill. this other just watched me and drove past. i got out immediately to check for damage but saw nothing out of place. it kinda freaked me out, thats the first time i ever lost control of my car. but now my dad wants to get me snow tires for my car. BTW i was using the stock 16' rims.

any suggestions on good tires for snow?>>

I'm in my second winter with my 2k and can say the stock 16" Toyos are pretty good in snow, and also not much less than studs will help with ice, though Blizzaks are pretty grippy. I can picture the problem you had - it is the largest fault with front wheel drive handling, and indeed the normal application of snows to the front only would have been worse. ---- The problem is this: You are going downhill in a low gear. The front tires have more static weight on them, downhill the weight transfer is to the front, decelerating the weight transfer is even more to the front. Therefore the front tires have much more traction than the rears and the fronts are trying to slow the car down. Now the rears want to pass the fronts - YAHOO - spin! Under normal circumstances you will notice that lifting off in the middle of a turn makes the nose tuck in - this was the extreme case.
To correct a skid you must turn the wheel in the direction of the skid.
The best thing you can do is find a big clear slippery parking lot and slide around every way possible, play with the ABS - even try handbrake turns.
If you go for snow tires be sure to get all four - this is much more critical for FWF than it was for RWD.

Dave

 

Well, I just have to add my two cents in here.. sorry..

First, the weight of each part of the car is irrelevant when going downhill in normal conditions.. Why? well, the acceleration due to gravity is the same regardless of the mass, which holds true on an inclined slope.. Therefore, in normal conditions the rear wheels do not "want to go faster" than the front... Quick experiment, get behind a semi, and going downhill, both of you just let go of the accelerator.. Now, even though both you and the semi differ in mass (by a LOT), your not going to have to slam on your brakes.... Why? because neglecting other factors (such as air resistance [the semi is a boxy shape], and differences in friction at the axle, etc..), you guys should be going roughly the same speed..

I say "normal conditons" above, because on an icy slope, it's a lil' different, and therefore a little counter-intuitive.. The back wheels tend to lose traction first.. Why?, because our Maxima's front is so much heavier than the back.. [in RWD vehicles, it tends to be at least a LITTLE more balanced] Therefore, the front tires exhibit more friction than the rear tires.. Now, if your not careful, and hit the brakes, chances are the the two tires in the front will not brake with exactly the same force, and bam!!! skid city... (in terms of the explanation above, the back continues going at roughly the same speed (because we're assuming that the back wheels lost traction), while the front slows down (still have traction)..

-Tom

PS.. weight is not shifted at any time, regardless of accelerations, de-acellerations.. Unless of course you have some really heavy bricks sliding around in your trunk??

**(or are accelerating somewhere near the speed of light, which I'm pretty sure is fairly illegal on most major US highways :-) **

 

You merely repeated what I said about traction and the rear passing the front except with two serious errors:

>>First, the weight of each part of the car is irrelevant when going downhill in normal conditions.. Why? well, the acceleration due to gravity is the same regardless of the mass, which holds true on an inclined slope.. Therefore, in normal conditions the rear wheels do not "want to go faster" than the front...<<

As I said - the situation was under engine braking - using a low gear to slow the car - therfore the front tires with more traction are trying to slow the car - the rear is still free to go downhill under the acceleration of gravity.

>> PS.. weight is not shifted at any time, regardless of accelerations, de-acellerations.. Unless of course you have some really heavy bricks sliding around in your trunk?? <<

Absolutely incorrect. The center of mass of a car is above the ground. Any acceleration force or inclination moves the weight distribution. That is why the nose dives under braking and the rear squats under acceleration and the car leans when cornering. On an incline the G vector is straight down, if the center of gravity is abve surface level the weight distribution is biased toward the downhill side.

Dave

 

Ya.. the engine braking plays a factor.. But I'm assuming that the engine is working evenly on both front tires In theory, it should be even on both tires... right?? , so that doesn't play a factor until you turn the wheel (ie. no longer travel in a straight line), and since turning the wheel changes the problem significantly, I didn't even go into details about that scenario (moral of the story, is don't switch lanes when going down an icy slope!!!)

I am assuming "G vector" is really "g vector", big difference, and if it isn't then you lost me somewhere in the beginning. But it was my understanding that the center of mass of a solid object does not change. Perhaps I'm wrong, but it just seems implausiable that weight distribution could change due to accelerations.. However, I have no hard facts to back up my statement about, so I can't really be certain..

-Tom

 

>>But it was my understanding that the center of mass of a solid object does not change. Perhaps I'm wrong, but it just seems implausiable that weight distribution could change due to accelerations.. <<

Correct - the center of mass doesn't change, but acceleration is a force acting on the center of mass. The center of mass in a Maxima is somewhere around the base of the shifter, not the center of the car or at ground level. The four contact patches are not at the center of mass, not equidistant from the center of mass nor at the same height as the center of mass.

 

Wait didn't you say something to the effect of "center of mass and weight distrubiton moving around" in a previous post??

<<---------->>

K.. you've managed to thoroughly confuse me (and that's usually a difficult thing to do)

#1. Acceleration is a force?? don't think so... its the rate at which velocity changes, by definition.. Which just translates rougly into how far down your holding the accelerator in a car... As far as I know, the amount of acceleration an object undergoes does not affect the placement of the center of gravity. for future reference, you could calculate the force by one of Newton's laws... Force = Mass * Acceleration

#2. For similar reasons, I think your confused, because you claim that acceleration is a force which acts on the center of mass..

ehhh.. not really.. There are many types of forces, and tons of ways in which you can accelerate something. You probably had the force of gravity PARTICULARLY in mind (which is a very unique and special force we don't even claim to understand) in which case, you can "pretend" that it is acting upon the center of mass of an object (wheras in reality, it is acting on every single particle).

#3.. Base of the shifter sounds about right to me (if I had to take a wild guess, I'd say it'd be a few inches behind the shifter), since the Maxima is heavier in the front... My whole problem here, is that as far as I know, the center of gravity STAYS there, regardless of what the car is doing!!!

And no, there is no possible way that you could make a car with center of mass at ground level... that's just absurd..

There is also no way in which you could make a car with center(s) of mass at the wheels. (again, absurd)

Distance from the center of gravity does not matter for our purposes, simply because your mathematically allowed to pick any arbitrary point when calculating torques..


->Tom

 

I realized the source of confusion about 5 minutes ago (this server is amazingly slow - took forever ((me too)).)

Mass and weight are not interchangeable terms. Weight is actually a force - 1 pound mass x 1 gravity = 1 pound weight. Indeed I misstated acceleration as a force - it requires force. Gravity is an acceleration of 1g. When you accelerate an object the resultant force (every action requires an equal but opposite reaction) acts through the center of mass. In the case of a car, the center of mass on level ground, not moving, gives a certain static weight distribution. Since the center of mass of the car is not at ground level, anytime you change the angle of acceleration (tilt, accelerate, decelerate, side accelerate), the resulting force (f=ma) acts as a vector through the center of mass to the four contact patches and the weight at each wheel is changed.
Center of gravity is an unfortunate, shortsighted term for center of mass, probably coined before we were able to make objects of mass weightless in space (the absence of the force of gravity).
Dave

 

Anyway - you can easily look up vehicle dynamics in any one of a number of racing books, pictures help. This doesn't help the kid who spun - he needs to go out and practice so he can avoid this problem in the future.

Dave

 

Originally posted by wdave

Mass and weight are not interchangeable terms.
Agreed... apples and oranges

[i]Weight is actually a force - 1 pound mass x 1 gravity = 1 pound weight.[i]
Agreed again... But little g only works on earth... (since we don't drive a whole lot of maxima's on other planets, there's no prob.. just wanted to be clear).. And I would avoid pounds like the plague.. Use Kg, it makes things SO much more convenient...


Indeed I misstated acceleration as a force - it requires force.
Yuppers... don't do it again :-)

Gravity is an acceleration of 1g.
Let's not get into the definition of gravity... I've seen many physics professor's throw a tantrum over this.. Apparently we're not sure what it is.. But we call it a force, not an acceleration nonetheless...

When you accelerate an object the resultant force (every action requires an equal but opposite reaction) acts through the center of mass.
Not true, not true... but we can sure "pretend" it does, because it turns out that all the math still works out correctly in the end


In the case of a car, the center of mass on level ground, not moving, gives a certain static weight distribution. Since the center of mass of the car is not at ground level, anytime you change the angle of acceleration (tilt, accelerate, decelerate, side accelerate), the resulting force (f=ma) acts as a vector through the center of mass to the four contact patches and the weight at each wheel is changed.
Well, since velocity is a vector, therefore acceleration must be a vector. Mass is a scalar, but when multiplied by Acceleartion gives another vector (force).. so Yes, you got me there on a technicality.. The force at the wheels does change, but I'm still not convined it has anything to do with a shift in center of mass or weight distribution, and weight is definitely not the word to use right here, force is a much more generally applicable term.


Center of gravity is an unfortunate, shortsighted term for center of mass, probably coined before we were able to make objects of mass weightless in space (the absence of the force of gravity).
I've seen both terms used interchangeably... The parenthesis do you in again... There is no direct and concrete corollation between "weightless" and "absence of gravity". Indeed an object in freefall (think space shuttle in orbit), can be "weightless", but the acceleration due to gravity up there is almost as strong as here on Earth. (around 9.7m/s I believe) Einstein did some fairly interesting work with this concept of "weightlessness".

-Tom

PS... let's just drop the topic... and agree that the kid does have to in fact go out and try some skids (preferrably on slippery surfaces)... [not in public places!!]

It may save a few lives one day!!!

 

1st time.... somewhere in upstate NYC... doing about 30mph on the highway... try to get out of the way of this big chuck of ice... spun... went down this ditch... good thing a Hummer stopped and towed me out..., second time, doing 20 mph... did nothing, the car just lost control... and the third time... doing 30 mph... just lost control of the car... the last two times are in WI.... that is why as soon as I graudated.. I moved to CA... NO MORE SNOW!!!!!

 

I spun a few times.. Mostly on icy local (smaller), low-traffic streets.. BUT!!

One time, I was on Rt. 22 (anyone from NJ will see where this is going), and doing about 55 mph, when a huge truck merged into my lane (from a complete stop) right in front of me!!!.. It had just started raining, and everyone knows that the road is pretty slippery when it JUST starts raining. I slammed on the brakes (with a lil pumpin action on the side --> no ABS!!!) (**dumbass move, since i wasn't in my maxima, but an 85' buick**), and the car just spun out (YES, on RT. 22) It was actually more of an uncontrolled skid, than a complete spin .. In fact, I went about halfway into a lane of opposing traffic before I stopped (There are cement barriers almost everywhere on Rt. 22 , but not where I spun!!! THANK GOD!!)..


I'm a lucky SOB, so nobody got hit.. I'm just thankful that the guy in the left lane was apparently a good driver, and saw me lose control, and let me skid through his lane...

Once you lose control, nothing but a lil' luck can save you from tragedy.. (assuming you know enough to regain control of the car)

Moral of the story #1 --> I shouldn't have tried to stop completely, but slowed down a lil', and hoped that I could find a spoot to merge into the left lane before smacking into the truck!!

Moral of the story #2 --> Sometimes your just at the wrong place at the wrong time... that's why we have insurance..!!


-Tom

 

I had RWD too... soo....
Anyhow Last thing I had was new this year...
BF Goodrich Winter Slaloms... Studded on the Rear Wheels and I hadn't had a problem

 

 

No, that was what I meant... your picturing the scenario occuring with respect to transverse motion, in which case you would describe it as "in"..

I was lookning at the angular motion of the car, and would describe the action as "out".. (picture a spin, since the directions should be clearer than a skid)..

Simply saying to "turn in the direction you want to go", isn't very helpful now, is it?? It's a very subjective thing, and would bother most people, since they always turn the wheel in the direction they want to go...

If we wanted to be absolutely certain that we're saying the exact same thing, there is a mathematical way... but that reuquires a few properties of vectors, and your right hand (no kidding). In which case, in your scenario, your rear end is skidding to the right, therefore the direction of the cars angular kinetic energy / momentum is "up" (no joke), and you turn the wheel to the right (to apply a torque "down") I would describe that as turning "out of the skid" (notice the difference in directions.. up/down)..


Moral of the story -- we both meant the same thing... But the only surefire way to get out of skids and spins is to practice a bit in controlled conditions (ie.. empty parking lot)..

 

The simple and direct way to state it is "turn in the same direction as the skid".