Hyundai Forum: Hyundai Performance Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
611 Posts
Discussion Starter #1
Do you reccomend downshifting when it is snowy/icy out to reduce your speed instead of using brakes? My mom swears up and down that this is the best way to do it... seems like when I do this, I lose traction nearly every time. So what are your opinions?:smoking:
 

·
Registered
Joined
·
7,256 Posts
You're gonna need to learn heel-and-toe so as to balance out the difference in traction between the gears, i.e. loading the contact patch evenly throughout the process. Since your car is FWD we cannot make the same manouvers as RWD; we actually have to downshift on the brake and then lead into the turn or we run out of traction[think of your tyre's tractive potential as 100%, on a bad surface it may go as low as 20% so we cant push our tyres too far if they're not condition specific.]

PS: This is based on driving on an oily[diesel] smooth concrete surface in the rain, the amount of traction you have in the snow may be even lower than that!
 

·
Registered
Joined
·
786 Posts
yes i think downshifting is the way to go. when i hit the brakes i just seem to slide all over the place. also you can tap on the brakes to simulate ABS if you dont have it. i think there is a happy medium when it comes to downshifting and braking you have to use the right combination of both at the same time for the most efective results.

also when you downshift are you staying on the gass or are you just letting the clutch out. if you stay on the gass your wheels will start spinning and you will lose controll. next time you are out try downshifting and just let the clutch out slowly and you should not lose controll

[body]You're gonna need to learn heel-and-toe so as to balance out the difference in traction between the gears[/body]
hmmmm i dont heel to toe and i can still downshift pretty smooth this isnt cart racing all you need to do is downshift quickly let of the clutch then you are free to brake as needed because you dont need to be on the gas. especially on a turn just coast through it and then hit the gass after you are straightened back out.

or

you can turn the wheel hard and pull the E-brake hard :D (my prefered method of taking snowy corners only if the intersection is clear though)

[Edited by CCSPMP on Jan 28, 2003 7:55 PM]
 

·
Registered
Joined
·
83 Posts
Downshifting to control speed on slippery conditions may not be such a good idea. If your on the street, rememer that your major concern is safety. It's a common practice and well known rule in truck driving, that the use of an engine brake in slippery conditions is to be avoided at all times. The forces acting on a tractor/trailer are different from that of a car, but the physics of traction are the same. Your downshifting is decelerating you because of an increase of compression in the engine. Thus, it is the engine that is braking the car by applying "negative torque" (I know there is no such thing as negative torque, but it helps to explain this). The resistance applied by the engine is slowing the spin of the wheels. This is the same thing your brakes are designed to do. You may now be asking; So what if the engine is braking instead of the brakes. Braking-schmaking (please excuse this highly technical lingo) it's all the same. You would be correct in saying this, but the problem is all in control and feel. When the engine is braking, you have little or no feel for the available traction or the amount of force that's being applied. This is normally transmitted through brake pedal. Your car can, very quickly, send too much braking force to the wheels and you will lose traction and die. While it is true that the amount of force can be controlled by the throttle, it's not recommended. With your car in a lower gear, your torque output will be greater. If you try to reduce engine braking by applying more throttle, you could very easily appy too much. The use of a higher gear is actually recommended in slippery conditions for this purpose. Available traction in snow is extremly low. The loss of traction comes suddenly. Remember, you should be focused on safety. Use your engine to go, and your brakes to stop.
 

·
Registered
Joined
·
12 Posts
I dont think downshifting in snow is bad, but remember that the prices of changing your brakes is really lower than changing the clutch or the transmission
 

·
Registered
Joined
·
7,377 Posts
i know downshifting is the snow/slippery surface is bad. you'll either burn out your clutch trying to do so or you'll wind up breaking the tires lose from the road. i've done it many times messing arround.
 

·
Registered
Joined
·
220 Posts
i live in contry that snow (just frost now.. very little snow now)

yeah good to use downshift.. just take car out of gear before you use brake
 

·
Registered
Joined
·
5,295 Posts
Laurie,

Growing up in NY and driving in winters there up until last year, I think braking is a better method of slowing down than using the engine. This topic was discussed in great length a few months ago, but I'll give you the summary version here:

When using the brakes, you are slowing all tires down somewhat equally. If you use the engine to brake by down shifting, your two front tires are slowing down. What you can possibly do in slippery situations is give your car and axis to pivot on (especially if you're like most people who put the better tread tires on the front of the car)... and the back end will come around...

I personally think you're better off braking to reduce speed, then downshifting in slippery conditions.

http://www.hyundaiperformance.com/forums/topic.php?t=16387
 

·
Registered
Joined
·
244 Posts
I'm going to go against the grain here and say that downshifting really is the best way to go.

Funny that you mention it, Tugger, but brake bias is one of the reasons why downshifting is a better idea. Typically, on a FWD car, braking is heavily biased to the front, which is one of the reasons why the car's nose dives as you brake. On cars with drum brakes on the rear wheels, this is even more pronounced, taking on a typically 90% front / 10% rear distribution. So engine braking really isn't that much different.

Additionally, engine braking provides a smooth, steady brake all the way to the entrance of a turn, at which point you can gently ease the power back on and use that slight accelleration to keep the rear wheels planted through the curve. With standard braking, you have to lift off the brake and then apply the gas. Additionally, downshifting ensures that you have maximum power... and more importantly, torque, available to you at any point during the process, providing manuverability if needed.


But the bottom line is, you shouldn't be braking or downshifting in icy conditions unless you are going in a straight line. Braking mid turn is going to put you in a ditch no matter how you do it. Brake sufficiently as you approach the turn and you'll be fine no matter the conditions.
 

·
Registered
Joined
·
5,295 Posts
In most cases, I would agree with except in extremely slick conditions.

I suppose it is a matter of driving style... However, I think it's easier to get your foot off of the brake (to pump it if you start to lose it) than to try and get back into your previous gear wear there is less power to the wheels. With the lower gear, the car will still understeer if there is power to the wheels (at least in the Accent).
 

·
Registered
Joined
·
3,943 Posts
ok...
if you have 4 wheel disc brakes youre brake bias is probably a constant 60/40 maybe 65/35. now look at your weight bias on a FF(fwd and front engine) car. about 55/45?? now if you are on dry road and braking hard; and youre putting say 70% of the cars weight on the front tires and only 30% left in the back. now applying 40% of braking power in the rear you can see that the back tires will slide before the front. however in the snow traction is greatly reduced; and your original wieght bias of 55/45 plus braking weight transfer the wieght ration may be as low as say 58/42. and with a 60/40 braking ratio you now notice that the front tires will lock up before the back ones. and if that is the case AND you downshift; youre just placing MORE brake torque on the front wheels ONLY; while you may have to let off the breaks altogether; giving the front tires 100% braking duty.

the goal is to match brake bias to available grip. the power assisted brake bias is a set constant but if MORE grip is available; more brake can be added to the front wheels as more weight is being placed on them. THAT is what downshifting is for and unless its on a dry or damp road downshifting can easily upset your car. i live in upstate NY i know this. if the sidestreets have slush or packed snow i will be using brakes only; and under moderation- but as soon as i turn onto a main road where its salted and plowed i will be right back to downshifting again.
this is just how it works guys :D
 

·
Registered
Joined
·
244 Posts
Originally posted by beppomarx
[body]
now look at your weight bias on a FF(fwd and front engine) car. about 55/45??
[/body]
I wish. :ermm:

60/40 at best. 70/30 at worst.

[Edited by qtiger on Feb 5, 2003 12:27 PM]
 

·
Registered
Joined
·
3,943 Posts
ok well if its that unbalanced then downshifting would help IF DONE CORRECTLY AND SMOOTHLY and evenly. but with drum breaks in the back such as an accent youll probably never lock up the back tires in the snow; so it wouldnt be worth it. it depends let me drive your car in teh snow and ill let you know. lol
 

·
Registered
Joined
·
142 Posts
I live in Canada and I think it is sucidal to downshift in snow. If you downshift in the snow, you are likely to loose front grip (steering's gone!) for a moment and that could make you slide and if you are not used to have your car moving a lot on the road you may overcorrect it and then end up in the ditch.
We have 4 tires on cars, let's use all of them for slowing down. Just be careful with the brake pedal. :) I don't see the point of downshifting in the snow since you only use 2 tires to slow down.

Also, it's very easy to lock 4 wheels in the snow in a car which has no abs, regardless of the brake config.

Wait, it's bad to use your engine to slow down to begin with, the new small engines are not made for that. They are made to generate energy not to absorb it.
[Edited by Moonrider GSI 2k2 on Jun 20, 2003 8:34 PM]

[Edited by Moonrider GSI 2k2 on Jun 20, 2003 9:06 PM]
 

·
Registered
Joined
·
145 Posts
i always down shift in snow as well as taping (or pumping) the brakes and when cornering you kind of want a side to side action then pulling the e brake (just for a second ) timing and practice is the only way to get good at this, back roads is where to do this as in any case of being an over aggressive on the streets ,this also depends on the conditions ie. ice, deep snow ,by the way whats with talking about driving in the snow its summer time we just got rid of that ****:nervous:
 

·
Registered
Joined
·
694 Posts
Okay, a lot of long explanations. My short answer:

If you have ABS, don't really need to. You are not going to stop the car any quicker, and locking the brakes is rather difficult ;):

If you don't, downshifting can't hurt. If you need to adjust your speed slightly, downshifting can do this without locking the wheels like tapping the brakes can.
 

·
Registered
Joined
·
1 Posts
Do you reccomend downshifting when it is snowy/icy out to reduce your speed instead of using brakes? My mom swears up and down that this is the best way to do it... seems like when I do this, I lose traction nearly every time. So what are your opinions?:smoking:
You have to learn an elementary things about driving on winter. Go easy on all commands ( steering, acceleration, brake, downshift and even lift off). Depending on the surface you may need to downshift gently or very gently to avoid loosing traction.
Also would be good to learn double clutch aka heel and toe.

Forget about people telling that you should protect the clutch because is expensive and to use only brakes... This is the way a car should be driven! (downshifting)

Use engine brake as much as you can, in any slowdown, slope, curve).
 
1 - 18 of 18 Posts
Top