Why do people sometimes change gear while going to a stop?

zyran

zyran

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Mar 21, 2004
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What I mean is like lets say we're doing 200mph and we want to stop. Why, with a manual transmission, do people still change gears according to the speed? Wouldn't it just be easier to brake with the clutch depressed? I saw this once in the Koenigsegg episode and he was doing 174 miles and while going to a stop he still changes gear according to speed. Anything to do with rev-matching?
 
No when you engage the clutch the engine has no friction on the wheels, when you're going from 5th to 3rd gear and 3rd gear is like 5000rpm, the engine has lots of friction, so the car will stop sooner, it's just done to brake quicker.

another thing is, when approaching a corner you want to be IN the gear before actually making the turn at high speeds, engaging gears IN the corner can lead to instability of the car..
 
yup... it is only used when you want to brake quicker.. try doing it in NFS :U2... it works as well
 
it's not quicker, if you press your brakes to the max you'll come to a stop sooner. but it's more comfortable for the passengers (their head isn't thrown forward -if clutch is released gently-), doesn't wear out the brakes, and it's safer, almost no chance you'll start sliding
 
its quicker if you brake till a certain speed... then shift down to increase the revs ( this would pull your speed down slightly)... release the clutch while still braking then at a certain speed, shift down again
 
It saves fuel too, if the car with his mass is "powering" the engine there is no (or less) fuel injected into the cylinders...
 
The medal has other side as always. Somebody say valves are wearing out that way...
And yes, injector engines almost consume no fuel when engine-braking. So you get better stopping power, save your brakes from overheating and save fuel. Not a bad deal.
And as Jostyrostelli pointed out, touching clutch in corners is not a good idea. You end up easily sideways when driving wheels momentarily lock up (when racing, or simply in winter), so you have to be in right gear before corner. Of course there is a problem engaging a lower gear under intense braking. Then a tricky heel & toe technique must be used for rev-matching :) But has nothing to do with engine braking of course...
 
MXM said:
heel & toe technique must be used for rev-matching
Click to expand...

I only do the heel and tow when I'm at high speed and I need to shift down to take the corner... on my Subaru... I had to do it so I could get my flywheel spinning to match the clutch so it grips together easier... most subaru drivers do it so they could save their gearboxes as it is very fragile
 
Another reason for doing this is simply "in case shit happens". Has nothing to do with braking from maximum speeds on an empty runway but in normal traffic, or racing etc. its good to have the gear engaged in case shit happens and you have to react quickly and possibly make an emergency manouver...
 
btw 4got... blipping the throttle b4 you shift down to corner sounds really nice as well... thats why I keep doing it in the RX-7 even though I don't need to as it has a stock clutch and flywheel
 
I had to put on sparco pedals to do it... my accelerator pedal wasn't long enough to do the heel and toe... btw I heard its really difficult to do it in BMW's because of the different way the pedal pivots... is that true?
 
Yeah heard something about that too, never tried that in a BMW though, heard the acceleratorpedal pivots to the right..kinda sucks
 
I find it hard to do in my car. Pivot axis is at the lower side of accelerator pedal, not in higher. So it's easier to press with side of the foot instead of heel. But pedals are little bit too far apart to sucessfully do it everytime.
I want something like this:
911pedals.jpg

:)
 
read the first post and was preparing what i'll write here, by the time I came to the end of the thread I found out it has all already been said, so I have absolutely nothing to say :D
 
yeah, a friend's girlfriend drives a E46 BMW 3, and he has been complaining to about the accl pedal. he showed it me once, and it does turn like the hinch is placed on top of the gearbox. very stupid
 
actually pressing the clutch and slamming the brakes is the fastest way to stop.

but doing that at 200mph isn't recommended since you take away all the power that was going to the rear wheels so a more conventionnal braking technique is better, and using the engine compression to slow you down helps reduce the effort on the brakes too.
 
Renesis said:
actually pressing the clutch and slamming the brakes is the fastest way to stop.
Click to expand...
That can't be true cuz u'll always stop faster with the extra engine braking....
 
it does provide power to the wheels, for the same reason that if you release the clutch too fast it'll jerk, and adding power when you want to stop = no good.

All brake tests are done to get the best results and guess how they do? they use the brake and clutch, no gear change
 
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