Re: compression braking

[SMILLER@xxxxxxxxxxxxxx]

Jason, there is a big difference between street driving and off-road
driving.  In off-road situations with a SUV or other 4 wheel drive vehicle,
traction is usually poor.  (Duh, that's why you're using 4 wheel drive,
right?)  The safest way to decend a steep hill is in 4 Low, transmission in
1st gear, foot off the brake, and just let it idle down the hill.  This keeps
the wheels turning.  When the wheels are turning, you can steer, which
is good.  

In this situation, if you use the brakes, you can easily lock up one or more
wheels and start sliding down the hill.  Sliding is bad, it means you're not
in control of the vehicle, and you can either slide into an immovable object
(tree, big rock, etc), or you can put a sliding tire into a ditch and flip the
vehicle over.

On the street, you're generally on pavement and have at least some
traction.  You're not too worried about locking up the wheels and sliding
into a tree or flipping over.  In this case it is more a matter of economics
than anything else.  Regardless of your rev-matching abilities, the more
times you operate the clutch and shift gears, the faster you will wear out
those parts.  In these situations, braking for slowing is better.

Having said that, I'll admit that I usually downshift one gear when coming
to a stop from 5th or 4th gear.  Mainly I do this just in case a change in
traffic conditions suddenly requires me to accelerate.  I'm already in a
better gear and can just hit the gas.  But mainly I use the brakes for
stopping.

Scott Miller
Golden Gate Chapter
BMW CCA #44977

>Date: Mon, 15 Mar 1999 15:58:02 -0800 (PST)
>From: Jason Bishop <jason@domain.elided>
>Subject: compression braking
>
>Ok, I ignored this thread until I saw the "overwhelming response" part. 
>What is wrong with compression braking?  I specifically bought an SUV
>with a manual gearbox specifically for going down hills.  As far as I'm
>concerned its the only way to go.  Just drop the transfer case into low4
>and idle down in 1st gear.  works great.  ABS can't touch it, because 
>the wheels won't lock, but they won't slip too much either (like ABS has
>a tendency to do).
>
>Don't see a problem with using same principle with my M3.  If you match
>revs then there is no wear on the clutch at all, and if the motor is
>slowing the car down, then there is no wear on the brakes either. 
>
>SUV is on original brakes at 65k miles and clutch is in good shape.
>
>Jason

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