downshifting vs braking
Thread Starter
Pro
Joined: Feb 2001
Posts: 606
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From: FL
Cruise-In II Veteran
downshifting vs braking
Downshifting vs braking
Hi all, :D
I was wondering which is better or worse on the car. I was always told to down shift any standard but I was talking to a mechanic over the past week and they said it tore up a clutch faster and to brake instead of downshifting.
Is this true? Just looking for some feed back on this.
CJ
:chevy :flag
Hi all, :D
I was wondering which is better or worse on the car. I was always told to down shift any standard but I was talking to a mechanic over the past week and they said it tore up a clutch faster and to brake instead of downshifting.
Is this true? Just looking for some feed back on this.
CJ
:chevy :flag
Team Owner
Joined: Aug 2000
Posts: 42,934
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From: Sydney, Australia
CI 6-7-8-9-10 Veteran
St. Jude Donor '07-'08-'09-'10-'11-'12-'13-'14-'15-'16-‘17, '22
Re: downshifting vs braking (Goody)
Which is cheaper to replace?? All the reving engine, tranny and driveline components or a couple sets of brake pads and maybe rotors? :rolleyes:
Racer
Joined: Jan 2002
Posts: 337
Likes: 0
From: Southern California
Re: downshifting vs braking (CJ454)
Depends on how much you want to slow down and what you want the car to do after you've slowed it down. If you want to accelerate out of a corner (after braking) then you'll want to do both. If you just want to stop at a traffic light then I'd suggest using the brakes. :D
Braking is a far more efficient means of slowing down a car than downshifting. Braking also results in less wear and tear on the drivetrain (as mentioned in the other posts).
However, unless the car is also in a gear while braking you might be giving up some level of control. For example, if the trans is in neutral, one foot is off the clutch, the other foot is on the brake, it will be very difficult to abruptly accelerate.
I'm sure that was the rational behind California Vehicle Code Section 21710 which states "The driver of a motor vehicle when traveling on down grade upon any highway shall not coast with the gears of such vehicle in neutral." (The implication is that even if your foot were on the brake you would still be giving up some level of control.) :eek:
......and for the record Your Honor, no, I'm not a lawyer or a policeman. :D
:seeya
Braking is a far more efficient means of slowing down a car than downshifting. Braking also results in less wear and tear on the drivetrain (as mentioned in the other posts).
However, unless the car is also in a gear while braking you might be giving up some level of control. For example, if the trans is in neutral, one foot is off the clutch, the other foot is on the brake, it will be very difficult to abruptly accelerate.
I'm sure that was the rational behind California Vehicle Code Section 21710 which states "The driver of a motor vehicle when traveling on down grade upon any highway shall not coast with the gears of such vehicle in neutral." (The implication is that even if your foot were on the brake you would still be giving up some level of control.) :eek:
......and for the record Your Honor, no, I'm not a lawyer or a policeman. :D
:seeya
Team Owner
Joined: Aug 2000
Posts: 42,934
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From: Sydney, Australia
CI 6-7-8-9-10 Veteran
St. Jude Donor '07-'08-'09-'10-'11-'12-'13-'14-'15-'16-‘17, '22
Re: downshifting vs braking (C4racing)
A few good points, C4racing. On the street, slowing while in neutral means if you need to accelerate or drive away from a possible (emergency or unseen) situation you'll be a sitting duck.
[Modified by Red 90 L98 Coupe, 1:45 AM 5/16/2002]
[Modified by Red 90 L98 Coupe, 1:45 AM 5/16/2002]
Burning Brakes
Joined: Feb 2002
Posts: 871
Likes: 1
From: Union KY
Re: downshifting vs braking (CJ454)
You've gotten sound advice in this thread. Common sence is the best guide. In traffic at 35 MPH on flat ground, coming to a red light, down shifting is silly. At 65 entering a turn that you'll exit at 45, it's a good practice.
One final word. DO IT RIGHT! Downshifting is a two footed action. The right foot "blips" the throttle to bring the engine speed up to sychronize with the speed of the lower gear you're going to. The clutch is not used to "drag" the engine up to the speed that the lower gear forces it to reach. What your mechanic is really saying is that if you downshift that way, don't. I have run several clutches (on perfomance cars) to 100K+ and downshift a great deal. Good luck getting the hang of this great driving skill. Cire96 :D
One final word. DO IT RIGHT! Downshifting is a two footed action. The right foot "blips" the throttle to bring the engine speed up to sychronize with the speed of the lower gear you're going to. The clutch is not used to "drag" the engine up to the speed that the lower gear forces it to reach. What your mechanic is really saying is that if you downshift that way, don't. I have run several clutches (on perfomance cars) to 100K+ and downshift a great deal. Good luck getting the hang of this great driving skill. Cire96 :D
Thread Starter
Pro
Joined: Feb 2001
Posts: 606
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From: FL
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Re: downshifting vs braking (CJ454)
Thanx all for the good info.
Can you tell me more on how to tell if the syncros are up to speed or not?
I am very interested in this I am sure it will take pratice.
Than again
CJ :chevy :flag
Can you tell me more on how to tell if the syncros are up to speed or not?
I am very interested in this I am sure it will take pratice.
Than again
CJ :chevy :flag
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Racer
Joined: Jan 2002
Posts: 488
Likes: 0
From: Woodstock GA
Re: downshifting vs braking (cire96)
Hey, thanks for the tip. I am a habitual downshifter and never even thought about the blip to pick up the RPMS. Also explains why I just bought a new clutch. :-)
It's my first standard car...but talk about a way to learn!
It's my first standard car...but talk about a way to learn!
Racer
Joined: Jan 2002
Posts: 337
Likes: 0
From: Southern California
Re: downshifting vs braking (CJ454)
The "blip" (aka "heel and toe" downshifting) is very important to make the drivetrain and engine components last. The trans was off of my car at about 75k miles and just for the heck of it I replaced the clutch. The car had a lot of competition miles on it including autocrosses and road courses and when the mechanic saw the clutch disk he asked me if I had recently replaced it because it looked almost brand new. :D
Burning Brakes
Joined: Sep 2001
Posts: 1,011
Likes: 0
From: Jupiter Florida
Re: downshifting vs braking (CJ454)
Can you tell me more on how to tell if the syncros are up to speed or not?
To add a little more to the already good explanation, lines of stress in the friction material on the clutch normally develop in one direction as a result of the motor trying to accelerate the vehicle. When you 'dump' the clutch on a downshift, the vehicle is now trying to accelerate the motor. Consequently the stress is built in the opposite direction in the friction material, causing it to break down more rapidly. Aside from the rapid clutch wear, the abrupt rear-wheel braking effect can be a really bad thing in a corner. This is why rev-matching on a downshift is a good idea. My .02 :)
[Modified by rocketfinger, 6:09 PM 5/16/2002]
Burning Brakes
Joined: Sep 2001
Posts: 1,011
Likes: 0
From: Jupiter Florida
Re: downshifting vs braking (JasonL)
Keep in mind, double-clutching should greatly extend the life if your synchros if you are a habitual down-shifter.
It will also be the only way to get in gear cleanly on an upshift once your synchros are lunched. I had one car that, thanks to the previous owner, had to be double-clutched into FIFTH. :crazy:
Double-clutching is letting the clutch out in neutral between gears so you're not just matching engine/driveline speeds, you're also matching transmission input/output shaft speeds prior to shifting.
[Modified by rocketfinger, 7:18 PM 5/16/2002]
Melting Slicks
Joined: Apr 2000
Posts: 3,198
Likes: 2
From: Northern CA
Re: downshifting vs braking (rocketfinger)
Double-clutching is letting the clutch out in neutral between gears so you're not just matching engine/driveline speeds, you're also matching transmission input/output shaft speeds prior to shifting.
You double clutch a shift like this...
(car is in gear)
press clutch
shift to neutral
release clutch
blip gas to proper rpm for next gear
quickly press clutch
quickly shift into next gear
release clutch
If you're good, you can do all this while braking and heel-toeing! :D (I sure can't, though)
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: downshifting vs braking (abigfoot)
Matching drive train speeds is a matter of "feel". Practice it and you will develope a feel for how much to blip the throttle to get a very close match.
I even downshift my A4 from OD to D just as crest a hill to use engine braking on the down grade. If I shift just before I let off the gas I can hardly notice the gear change, but once started down the hill it's very noticible and so taking a toll on the clutches.
The basic idea is to train your moves so that you cannot feel the gear change at the instant you complete the shift. Practice.
I even downshift my A4 from OD to D just as crest a hill to use engine braking on the down grade. If I shift just before I let off the gas I can hardly notice the gear change, but once started down the hill it's very noticible and so taking a toll on the clutches.
The basic idea is to train your moves so that you cannot feel the gear change at the instant you complete the shift. Practice.
Melting Slicks
Joined: Apr 2000
Posts: 3,198
Likes: 2
From: Northern CA
Re: downshifting vs braking (Captain_Kaboom)
Cool! Thanks for the description. Now, would there be any reason to double clutch while shifting into a higher gear?
But as someone mentioned, if the synchro is dead, you will need to double clutch an upshift to get into that gear without grinding :)
I've only driven modern syncronized manuals though! Older gearboxes are probably different.
