Downhill: brakes or in gear?

[Hendog]

There's a couple threads about when to up shift, when/if to downshift but how about leaving your engine engaged on a down hill slope to maintain speed? There's one particular slope on my way home where I leave it in gear and allow the engine drag to keep my speed even. If I need to add a little speed all I do is touch the gas.

[911pcars]

It depends on the hill.

On curvy mountain roads, the suggestion is to keep it in gear. You have less vehicle control when you disconnect the drive wheels from your foot.

On straight-shot gradual downhills, I would put it in neutral, maybe even play "hybrid" and shut off the engine (don't do this if you have power brakes in your 911). I wouldn't coast in neutral on any hill that resembles those in San Francisco.

In either case, you shouldn't continually ride the brake pedal as this may overheat the pads. In that case, leave it in gear and use engine compression and brakes to help maintain a controllable vehicle speed.

MHO,
Sherwood

[carnutzzz]

Always in gear.

I would NEVER turn my car off while operating it. If the ignition were off and steering wheel locked you would be fuched. You also lose the ability to accelerate and avoid a situation that may arise.

[911pcars]

If your vehicle has a steering wheel lock, don't do this at home. It's dangerous.

Sorry, I overlooked those cars, most cars, with steering wheel locks. Mine doesn't have one ('69). In addition, I would only coast with engine off if traffic and road conditions were ideal.

The "Grapevine" is a long stretch of road climbing to/from the central CA valley into the L.A. basin. I coasted in our Camry Hybrid for many miles. 80 mph; engine and electric motor normally OFF (but charging). Might do the same in the 911 some day if only the SUVs and minivans would stay out of the no. 1 lane, blindly blocking all those behind them.

Sherwood

[defcon65]

Every time I follow someone who rides their brakes downhill, I imagine another Midas shop being constructed. The preferred way to reduce speed on hill descents is to crest them at lower initial speeds and use engine braking.

The only time I coast in neutral is rolling up to stoplights.

[rs6er]

One other reason to not turn off your engine. Iff you have a cat, you will fuch it up.

[911pcars]

Originally posted by rs6er
One other reason to not turn off your engine. Iff you have a cat, you will fuch it up.

How does that work?

Sherwood

[ChrisBennet]

Taking it out of gear going down hill is also illegal last I knew...
-Chris

[SandyI]

Originally posted by ChrisBennet
Taking it out of gear going down hill is also illegal last I knew...
-Chris

Not in Caifornia.

[ChrisBennet]

Originally posted by SandyI
Not in Caifornia.

"Coasting Prohibited
21710. 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. "
Division 11, Chapter 3, Article 2, Section 21710
http://www.dmv.ca.gov/pubs/vctop/d11/vc21710.htm

[rs6er]

Originally posted by 911pcars
How does that work?

Sherwood

Don't really know, but every manual I have ever read says that.

[SandyI]

Originally posted by ChrisBennet
"Coasting Prohibited
21710. 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. "
Division 11, Chapter 3, Article 2, Section 21710
http://www.dmv.ca.gov/pubs/vctop/d11/vc21710.htm

Not to split hairs, but the key word in that sentence would be "highway." Which I completely agree with. I was refering to an occasional slow speed coast downhill at non-highway speeds.

But, um, are you part of some Rules Of The Road Club?

[ChrisBennet]

Originally posted by SandyI
Not to split hairs, but the key word in that sentence would be "highway." Which I completely agree with. I was refering to an occasional slow speed coast downhill at non-highway speeds.

But, um, are you part of some Rules Of The Road Club?

Just fighting ignorance 'best I can.
-Chris

[rusnak]

replacing brakes is cheaper than replacing transmission and clutch parts.

[SandyI]

Originally posted by rusnak
replacing brakes is cheaper than replacing transmission and clutch parts.

But if you match your revs on your downshift, and keep the car in that lower gear to hold your speed in check, you save wear and tear on both. My 901 tranny is REALLY effective on the steep downhill twisties I drive every day to work.

[Dantilla]

Once when I had a 912E, I coasted from the Paradise parking lot on Mt. Rainier all the way to the Kautz Creek mud flow with the engine off. About 12-13 miles, or thereabouts. No power steering pump, no power brakes, no problems.