Using 'B' Mode

[Marvinh]

I'm wondering. Has anyone tried starting off in 'B' mode in snow? I'm thinking 'B' mode might avoid some wheel slippage because it holds back some torque? Similar to starting off in 2nd gear with convention cars?

Any thoughts? Thanks! Marvin

[hobbit]

It doesn't hold back any torque; driving forward in "B" or "D" is
exactly the same. The behavior difference comes when you let your
foot up; see this for details. If you like the feel of the car
"falling on its face" with stronger drag at zero go-pedal in the
snow, then by all means use it. Downside is that the engine will
continue to run, even if it's just got to idle, until you move back
to "D". When you're negotiating slippery stuff and want generally
quicker response, though, you might find it valuable.
.
To avoid wheelspin, just be gentle on the pedal. Search the forums
for "traction control" to find a litany of sob-stories about it.
.
_H*

[Neicy]

I did exactly that last year when I first got my car in Feb. It worked very well. There are certain roads I drive when going to and from work where I need to stop in an incline. If it has been snowing for awhile, but the streets have not been sanded, I find "B" useful since I barely have to touch the brakes to come to a stop.

Now that I have more experience with how this car handles, I probably will find less need for it this year.

[Bohous]

I haven't used it to avoid wheel slipping but I use it going down even small hills to avoid using the brakes. I'm not sure if it makes any difference with the Prius brakes but I've always down shifted with previous cars so I still do it.

[qbee42]

B mode does nothing to avoid wheel spin. As for not needing to use the brakes, B mode does its braking through the front wheels, just as regen braking does. There is no inherent advantage to braking with B mode in slippery conditions, other than a placebo effect. The only use for B mode is burning off excess energy on long or very steep hills.

Tom

[patsparks]

<div class='quotetop'>QUOTE(Bohous @ Oct 28 2007, 12:43 PM) [snapback]531422[/snapback]</div>

I haven't used it to avoid wheel slipping but I use it going down even small hills to avoid using the brakes. I'm not sure if it makes any difference with the Prius brakes but I've always down shifted with previous cars so I still do it.
[/b]

How is your milage? because you are throwing energy into the air in the form of heat rather than storing it in the battery to use later. light brake aplication, just enough to make the brake lights come on will acelerate regenerative retardation without friction brakes while putting the car in B will make the internal combustion engine(ICE) spin against compression thereby dumping energy as heat from the exhaust and cooling system.

I use B when my battery is full, the HSD will spin the ICE at that stage anyway but it gives a bit more engine braking to do it manually.

[Pinto Girl]

Press on the brake a bit, while giving it some throttle; this seems to trick the traction control and might give you half a chance of getting moving when it's slippery.

[qbee42]

<div class='quotetop'>QUOTE(Pinto Girl @ Oct 28 2007, 12:19 AM) [snapback]531448[/snapback]</div>

Press on the brake a bit, while giving it some throttle; this seems to trick the traction control and might give you half a chance of getting moving when it's slippery.
[/b]

Hmmm, interesting idea. I haven't tried that one. I'll give that a try next time we get some snow - should be soon.

Pinto Girl, do you think this works because the friction brakes add some drag to the drive wheels? That would be my guess - kind of a poor man's posi-traction.

Tom

[Bohous]

<div class='quotetop'>QUOTE(patsparks @ Oct 27 2007, 11:51 PM) [snapback]531438[/snapback]</div>

How is your milage? because you are throwing energy into the air in the form of heat rather than storing it in the battery to use later. light brake aplication, just enough to make the brake lights come on will acelerate regenerative retardation without friction brakes while putting the car in B will make the internal combustion engine(ICE) spin against compression thereby dumping energy as heat from the exhaust and cooling system.

I use B when my battery is full, the HSD will spin the ICE at that stage anyway but it gives a bit more engine braking to do it manually.
[/b]

Well, considering the circumstances we are talking about (driving down an icy hill) I don't give much thought to my mileage or pay much attention to my consumption screen. I don't drive around town in "B", I'm just saying that if it's icy and I am descending a hill I feel more comfortable letting the transmission keep me slow and steady rather than my brakes. Like I said in my initial post, I don't even know if it's even beneficial from a safety standpoint. It stems from history of driving cars without ABS and fearing locking up the brakes.

[patsparks]

<div class='quotetop'>QUOTE(Bohous @ Oct 29 2007, 09:23 AM) [snapback]531716[/snapback]</div>

Well, considering the circumstances we are talking about (driving down an icy hill) I don't give much thought to my mileage or pay much attention to my consumption screen. I don't drive around town in "B", I'm just saying that if it's icy and I am descending a hill I feel more comfortable letting the transmission keep me slow and steady rather than my brakes. Like I said in my initial post, I don't even know if it's even beneficial from a safety standpoint. It stems from history of driving cars without ABS and fearing locking up the brakes.
[/b]

I'd let the ABS do it's stuff. I did some training with our patrol cars on soft gravel roads and with the brake pressed hard locking the wheels I could still steer the car easy. I must admit I have never seen snow so take what I say with a grain of salt. If you haven't used ABS before it can be scary due to noises and pedal pulses but it works great. Practice an energency swerve under hard brakes in a gravel carpark with lots of room at about 50km/h to get a feel for it.