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Old 08-20-2007, 07:57 PM
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Downshifting vs. Braking

So today as I walked home, it was a little wet and i was wondering to myself about downshifting vs. braking. Conventionally, brakes will slow you down much faster then downshifting and downshifting isn't too good for your car's tranny so i've heard. So say you're driving in slush or snow, bad conditions. if you step on your brakes by the time ur tires try to grip and ur ABS tries to stop lock up it takes forever for you to stop. Now in this situation if you were to downshift would you slow down faster because you use the engines power which slows the car down but could that lead to locking up the wheels and skidding?

Basically my question is, in terrible traction conditions, would downshifting cause ur tires to lock up and or be better then applying brakes.

Thank you and i hope to look forward to yet another interesting discussion!
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Old 08-20-2007, 08:24 PM
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I suppose if you are terrible at downshifting it could happen. I've seen 16 y/o noobsauc3's chirp the tires wile stopping on dry pavement.
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Old 08-20-2007, 08:35 PM
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Well you shouldnt be trying to brake at the maximum capability of the car, meaning the ABS shouldnt be anywhere near trying to activate.

I'd say though in slippery conditions, anyone other than a professional would more likely skid the car using engine braking than conventional braking, as they'll be getting sudden jerks through the car as they go through each lower gear, each one unsettling the car. If you know what youre doing you can do engine braking without unsettling the car, but having never compared double de-clutching to simply letting the synchros do their job, i wouldnt know how they compare to how effectively they slow you down.
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Old 08-20-2007, 08:36 PM
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Downshifting. If you downshift properly it won't do any damage to the transmission and if you do it slowly and preferably double clutch it gives you much more traction in the wet. A really good driver knows that brakes are really for slowing down the RPMs in order to downshift properly and not immediately stopping.
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Old 08-20-2007, 08:37 PM
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I wouldnt mind being called a n00bsauc3 if i could have a car with a manual trans.
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Old 08-20-2007, 08:38 PM
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what is this... snow?
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Old 08-20-2007, 08:51 PM
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Quote:
Originally Posted by whiteballz View Post
what is this... snow?
I'll UPS some to you in a couple months


BTW ABS is for the weak.
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Old 08-20-2007, 08:52 PM
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yup wet slushy snow! that even if you use ur brakes, eventually ur ABS kicks in cause u have no traction, its happened here in NYC

now what about downshifting in a car with a semi auto. for instance a G35 u can downshift the car, it won't let you do it early but when it can it will does that damage and if u do it and ur car starts to skid could traction control do anything? the enigne isn't gettin throtttle its trying to slow down but is spinning fast
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Old 08-20-2007, 08:59 PM
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Quote:
Originally Posted by coolieman1220 View Post
yup wet slushy snow! that even if you use ur brakes, eventually ur ABS kicks in cause u have no traction, its happened here in NYC

now what about downshifting in a car with a semi auto. for instance a G35 u can downshift the car, it won't let you do it early but when it can it will does that damage and if u do it and ur car starts to skid could traction control do anything? the enigne isn't gettin throtttle its trying to slow down but is spinning fast
Imagine that. Snow in NYC.
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Old 08-20-2007, 09:18 PM
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One thing I can see in your G35 example is that if you do a downshift instead of braking in that condition, all that is going to affect if the rear wheel, which is more likely to cause instability issue in bad condition. Though in an auto G35, as you noted it won't let you downshift when it doesn't get the right rpm, which probably minimize the chance of it being jerky on the downshift to upset the balance of the car....Personally in my G35 in winter(auto also) I do downshift first before I get on the brake, though to note this is in no emergency condition. As in winter anyway I usually don't try to gamble on making any corner at any significant speed....
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Old 08-20-2007, 09:29 PM
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Traction control wont do anything if your brakes have locked up under braking. You need things like ABS, EBD and stability control for that which can actually electronically monitor the brake loading.

Also, unless youve got snow chains or studded tyres, which it sounds like you definately need for the conditions, you shouldnt be on the roads. Even then, you need to allow much longer braking distances.
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Last edited by fpv_gtho; 08-20-2007 at 09:32 PM.
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Old 08-20-2007, 09:59 PM
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You definitely don't need snow chains or studded tires for slush.
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so i had to dump acid into the block tank today
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Old 08-20-2007, 10:52 PM
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OK then fair enough. Still wouldnt hurt to allow a bit more room to brake though
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Old 08-21-2007, 12:38 AM
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Quote:
Originally Posted by baddabang View Post
You definitely don't need snow chains or studded tires for slush.
i think the conditions dictate whether you need chains baddabang the F1 driver
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Old 08-21-2007, 01:16 AM
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Originally Posted by h22a View Post
i think the conditions dictate whether you need chains baddabang the F1 driver
German ordinary people regularly drive their families up a mountain in the Alps through a couple of centimeters of snow. That also without ABS,ESP. It all depends of the driver and his experience.

In certain conditions both systems help, but for example, driving in snow with ABS is extremely dangerous. It is learned to us on school, that it is better to try and bury the wheels in a layer of now or other shit creating resistance than to skid over it...

A good driver also needs no ESP. He knows the limits of his vehicle and can adjust his driving to that. He can also quickly respond to sudden situations and correct.

To the point of downshfting again. I do it every time I stop, every traffic light and or urban situation (if possible). I think if you let the clutch slip a little you won't get any sudden reaction of the vehicle, but will drive smoothly. The hardest thing of shifting is making the gear changes unfeelable for your passengers...
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