Iced over roads- Settings for traveling in such

[CrazyOldMan]

No idea I am afraid what high‑performance winter washer fluids w/ low freeze points are legal and available in Texas given state-specific restrictions on volatile organic compounds (Prestone?!). I am not aware of a distinct winter fluid thread but think I have seen discussions on this forum. I use the cheapest, and plenty if there is a lot of salt, no issues. I wanted heated valves but not sure if my ride has those.

Just for what it’s worth - I used a lower freeze point windshield fluid. The spray nozzle started plugging up, so I took it to my Ineos dealer. They said to ONLY use the cheap standard windshield fluid. That surprised me.

 

[HeavyFoot]

You're clearly not a prepper!
You never know when a pandemic, storm, bushfire or atomic event is going to happen
Become a prepper. Prepping makes sense - and saves fuel
We get our TP delivered because we give a crap about prepping

We smart and civilized preppers use bidets and save the paper

 

[Tazzieman]

We smart and civilized preppers use bidets and save the paper

So fresh drinking water always on tap? Fancy!
Our TP is recycled

 

[HeavyFoot]

So fresh drinking water always on tap? Fancy!
Our TP is recycled

Saves space. Drinking fountain/butt washer. What could go wrong!?

 

[Tazzieman]

Saves space. Drinking fountain/butt washer. What could go wrong!?

Even the word ice used to have a squeaky clean and innocent meaning!

 

[Tom D]

The other advantage of locking the CDL is that you are also equalising braking force between the axles. Makes a big difference to stopping distance on loose of slippery surfaces. I know these days we have ABS but even then I think it still makes a big difference.

 

[CrazyOldMan]

The other advantage of locking the CDL is that you are also equalising braking force between the axles. Makes a big difference to stopping distance on loose of slippery surfaces. I know these days we have ABS but even then I think it still makes a big difference.

OP is driving on paved roads in Texas - just a little ice over the next couple days.

 

[Tom D]

OP is driving on paved roads in Texas - just a little ice over the next couple days.

As soon as the road goes white I lock mine, you can do it on the fly... Just remember to unlock it as soon as the road is black again..

 

[cdsvt]

We drive in ice and snow regularly. Slow down. Give extra following and stopping distance. You don't need locked diffs. Your tires have a traction budget - braking and turning use up this budget - so brake when going in a straight line when possible. Use subtle steering inputs. Easy peasy.

 

[CrazyOldMan]

We drive in ice and snow regularly. Slow down. Give extra following and stopping distance. You don't need locked diffs. Your tires have a traction budget - braking and turning use up this budget - so brake when going in a straight line when possible. Use subtle steering inputs. Easy peasy.

Exactly - no need to freak out. But I eagerly await the complete breakdown of society in the US over the next 48 hours during this storm. I stocked up on groceries and booze and am ready to watch the show.

Do not take this agreement as any form of ceasefire between Wisconsin and Vermont. This cheese and maple syrup war will be fought to the bitter end.

 

[GN4HIR]

Most likely you won't need to adjust anything if you're going to be on roads. Just make sure to have a blanket and box of granola bars.

But remember, even though your vehicle may be capable, that doesn't mean the Chevy Cruze in front of you is and if they get stuck and the cars around you get stuck that means you're stuck too.

I'm in Buffalo and we've had more than a handful of storms where people had to stay in their car for 24 hours plus on the thruways because the folks around them got stuck.

I'm in Houston. If there is a chance of snow or ice we buy out the local grocery store, work from home, and tell stories of the great freeze.

 

[DenisM]

I'm in Houston. If there is a chance of snow or ice we buy out the local grocery store, work from home, and tell stories of the great freeze.

Is that when others phone you to say ".... we have a problem"...?

 

[255/85]

I see your point but on ice and hard packed snow I personally find esp and abs less useful - they’re too intrusive

Do you turn ESC completely off? I'm unused to electronic traction control sytems.

 

[Baron von Teuchter]

When you lock the CDL it turns off automatically

 

[cdsvt]

Do you turn ESC completely off? I'm unused to electronic traction control sytems.

ESC will help you drive in slippery conditions. Leave all systems the same as dry roads and drive with additional caution.

I love my lockers, low gear, being able to turn off nannies, but that isn't necessary for driving on your typical road under winter driving conditions.

I've been commuting about 90 miles a day in the northeast US in all weather conditions and haven't yet had the need to engage the center locker or mess with disabling safety systems like ESC.

 

[cdsvt]

The other advantage of locking the CDL is that you are also equalising braking force between the axles. Makes a big difference to stopping distance on loose of slippery surfaces. I know these days we have ABS but even then I think it still makes a big difference.

Would you be willing to explain your thinking?

As far as I know the braking system is a mechanical hydraulic system with fixed front and rear pressure distribution* that would be unchanged by whether or not the center differential is mechanically locked inside the transfer case.

* I haven't looked closely to see if there is a mechanical load sensing proportioning valve that alters front to rear brake force distribution between front and rear based on cargo loads, but even if there is, it is irrelevant to this discussion.

 

[Baron von Teuchter]

It’s just the action of the CDL. Braking (which would normally be biased to the front axle) slows the rear axle at the same rate as the front - removing the biasing of the braking system.

It’s been mentioned a few times on this thread and is a function of any 4x4 with a CDL. It’s a noticeable effect, if you’re lucky enough to have some snow and ice it’s a good excuse to go and have a play with it, test it so you can see how it feels with and without the locker engaged.

Have fun - and report back!

 

[Tom D]

Would you be willing to explain your thinking?

As far as I know the braking system is a mechanical hydraulic system with fixed front and rear pressure distribution* that would be unchanged by whether or not the center differential is mechanically locked inside the transfer case.

* I haven't looked closely to see if there is a mechanical load sensing proportioning valve that alters front to rear brake force distribution between front and rear based on cargo loads, but even if there is, it is irrelevant to this discussion.

I know this to be true from the defenders that I have owned previously, which have a near identical transmission. I can explain in theory as follows, (and next time we get some snow I'll go out and see if I can demonstrate in practise)
So when braking weight shifts forwards off the rear wheels and onto the front so if all things were equal the rear wheels would lock up very easily.
To counter this manufacturers fit much larger more powerful brakes to the front than the rear, the idea being that the fronts will lock up around the same time as the rear.
This brake bias attempts to get the maximum performance out of the brakes.
In practise the fronts are designed to nearly always lock up first as a front end lock up is much safer and easier to control than a rear end lockup. (imagine yanking on the handbrake)
All the above is optimised for asphalt surfaces. On a very low friction surface such as wet grass, mud or snow/ice the more powerful front brakes will always win out locking the front wheels well before the rears, on an old car with no ABS this will result in understeer, with ABS the system will activate. ABS gives better performance than a locked wheel and maintains handling, but the brakes are letting go and grabbing repeatedly, on low traction surfaces they have to let go a lot.
So the issue is on snow even light braking pressure will lock the front wheels and cause the ABS to kick in, at this point due to the brake bias the rear brakes are doing very little.
By locking the CDL the front axle can only lock up if the rear does too this is essentially sending some of the braking performance from the larger front brakes to the rear axle. Because the front axle can't lock as easily the ABS can spend more time in the grab position and less time letting go.. ( all of this happens many times a second )

If you have snow just now head out and try a straight line braking test from a low speed, maybe 30mph, with the CDL unlocked, and then repeat with it locked. compare the performance..

 

[cdsvt]

A lot of what you said makes sense based on your observations from behind the wheel.

Could you connect it to the vehicle systems and how that impacts brake bias?

By brake bias I mean the percentage
of braking force distributed between front and rear in the braking system (master cylinder to brake caliper), like your 70% front brakes, 30% rear brake bias example.

In these brake systems, bias is determined by how much brake force makes it to the front and rear circuits, and is either fixed by design, or has an adjustable proportioning valve between the master cylinder and rear brake circuit (some are load sensing adjustable valves, and some are manual, usually aftermarket additions in my experience, for builds like race cars or off-road vehicles).

From a vehicle systems point of view the center diff only locks the front and rear driveshafts mechanically within the transfer case (and has electrical switches to do things like disabling ESC/ABS, activating dash indicators, etc).

Each axle still has an open diff, so even if the center differential is locked, the wheel with the least traction on each axle will get the most torque and likely spin (unless front/rear diffs are locked, the differentials are open differentials).

The braking and powertrain mechanical systems aren't physically linked. So there is no way for the front to rear brake bias (brake force distribution) to change when the center differential is locked.

As I understand it, with the center differential locked, the the ESC/ABS are automatically disabled, so the most likely scenario on a uniformly slippery surface is to have one wheel spinning front and rear, and one wheel not turning front and rear. Since ESC and ABS are disabled, they won't attempt to slow the spinning wheels, and there will be virtually no power being put to the ground.

It may be perceived differently from the drivers seat.

(we have snow and ice on the ground and roads now, -2 F, and I have vehicles that have the gamut of 4wd braking systems, a '94 Land cruiser with ABS and LSPV removed on 35s, a Golf R with every safety nanny under the sun, a 200 series land cruiser with lockers and lots of nannies many of which can be disabled, an all wheel drive Honda CRV, a Land Rover Disco 2,and the Ineos).

 

[Baron von Teuchter]

It’s the same effect if you fail a hill climb without CDL. You can be on the brakes but can still roll back. Engaging the centre lock (if you have one) will stop this.

Robert Pepper did a good video explaining it here

View: https://youtu.be/QCPlK5CJ9uI?si=AoH26AYlYImFiFJ3