Re: highway speed in full time 4X4?
 

With a vehicle as short as a Jeep, locking the rear wheels will cause it
to go snaky like a bike does, but you can't lean out of it. A bike also
has the gyroscope effect big time with at least the front wheel still.

A longer vehicle will also act the same, but it is a bit more forgiving
so you can maybe hold it straight with the steering wheel.

Once it breaks free, not many people can hold the vehicle straight.

Locked up the rear tires slide way faster than the free turning front
ones.

We used to do this on purpose when racing on ice roads or frozen lakes
to help get around corners faster.

In part time 4x4 when you lock up the brakes, all 4 wheels lock for the
reasons you think.

This just up and slides you sideways into the ditch or straight off the
corner.

This action is a fast 'low side finder' like a locker on ice and is one
reason I think you see so many SUV's calmly sitting sideways in the
ditches during snow storms.

I always highly recommend folks new to 4x4 hit an empty parking lot and
try it out come first snow. The braking action in 4x4 is like nothing
else you have ever driven.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Tim Hayes wrote:
>
> Mike Romain wrote:
>
> > Locking the rear wheels at speed causes instant 360's. Try mashing
> > the e-brake on while driving 50 mph across an empty parking lot or on
> > a frozen lake.
>
> What causes this? Please excuse my ignorance, but I've done this on
> slick roads at speed on my motorcycle several times and never been spun
> around. (My bike doesn't have ABS or linked f/r brakes.) The rear does
> get 'sloppy' and move all over the place, but it doesn't cause a bike to
> immediatly swap ends. Why is a Jeep so different?
>
> And as a second question (not necessarily to you Mike)- if you are in
> part-time 4wd how is it even possible to lock the rear without locking
> the front and ever get into a situation like that in the first place?
> Don't the front and back have to turn at the same speed?

Re: highway speed in full time 4X4?
 

On 08 Jan 2004 06:13 AM, Mike Romain posted the following:
> Ok, what 'should' I call it?

You could call it a proportioning valve. 8^)

----------------------------------------------------
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Re: highway speed in full time 4X4?
 

On 08 Jan 2004 06:13 AM, Mike Romain posted the following:
> Ok, what 'should' I call it?

You could call it a proportioning valve. 8^)

----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
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Re: highway speed in full time 4X4?
 

On 08 Jan 2004 06:13 AM, Mike Romain posted the following:
> Ok, what 'should' I call it?

You could call it a proportioning valve. 8^)

----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
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Re: highway speed in full time 4X4?
 

And what did they design the proportinging valve to do?
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Del Rawlins wrote:
>
> You could call it a proportioning valve. 8^)
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/

Re: highway speed in full time 4X4?
 

And what did they design the proportinging valve to do?
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Del Rawlins wrote:
>
> You could call it a proportioning valve. 8^)
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/

Re: highway speed in full time 4X4?
 

And what did they design the proportinging valve to do?
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Del Rawlins wrote:
>
> You could call it a proportioning valve. 8^)
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/

Re: highway speed in full time 4X4?
 

Roughly 1/7/04 13:48, CRWLR's monkeys randomly typed:


>
> I always thought the job of the portioning valve was to balance the braking
> "power" equally, or proportionally, between the front and rear brakes.
> Without the portioning valve, the rear brakes, especially on a front disc
> brake system would not have the proper braking pressure appled even if the
> brakes were properly adjusted.
>

Or on a combination disc/drum brake system or pure drum/drum or
anywhere that weight transfer unloads the rears so they tend to
lock up if fed the same hydraulic pressure as the fronts.

Actually I've been wondering why this topic is relevant for Jeeps?
Is the addition of a brake proportioning valve some sort of
recent ["recent" in terms of someone other than Bill H.]
mod or something?

I can remember drum/drum brake systems that had a proportioning
valve to send more to the front brakes to avoid rear lockup
due to weight transfer waaayyyyy back on sports cars and
in the 60's on 'merkin ones.

Re: highway speed in full time 4X4?
 

Roughly 1/7/04 13:48, CRWLR's monkeys randomly typed:


>
> I always thought the job of the portioning valve was to balance the braking
> "power" equally, or proportionally, between the front and rear brakes.
> Without the portioning valve, the rear brakes, especially on a front disc
> brake system would not have the proper braking pressure appled even if the
> brakes were properly adjusted.
>

Or on a combination disc/drum brake system or pure drum/drum or
anywhere that weight transfer unloads the rears so they tend to
lock up if fed the same hydraulic pressure as the fronts.

Actually I've been wondering why this topic is relevant for Jeeps?
Is the addition of a brake proportioning valve some sort of
recent ["recent" in terms of someone other than Bill H.]
mod or something?

I can remember drum/drum brake systems that had a proportioning
valve to send more to the front brakes to avoid rear lockup
due to weight transfer waaayyyyy back on sports cars and
in the 60's on 'merkin ones.

Re: highway speed in full time 4X4?
 

Roughly 1/7/04 13:48, CRWLR's monkeys randomly typed:


>
> I always thought the job of the portioning valve was to balance the braking
> "power" equally, or proportionally, between the front and rear brakes.
> Without the portioning valve, the rear brakes, especially on a front disc
> brake system would not have the proper braking pressure appled even if the
> brakes were properly adjusted.
>

Or on a combination disc/drum brake system or pure drum/drum or
anywhere that weight transfer unloads the rears so they tend to
lock up if fed the same hydraulic pressure as the fronts.

Actually I've been wondering why this topic is relevant for Jeeps?
Is the addition of a brake proportioning valve some sort of
recent ["recent" in terms of someone other than Bill H.]
mod or something?

I can remember drum/drum brake systems that had a proportioning
valve to send more to the front brakes to avoid rear lockup
due to weight transfer waaayyyyy back on sports cars and
in the 60's on 'merkin ones.