AWD Braking Discussion: Ideal Brake Force Distribution

[SUMOTOY]

A couple of clarifications here. First any *warning* in relation to post #1 is N/A. No where in -this- thread do I *advocate* suggest or advise anyone to drive around with the CDL locked. What I propose in post #1 is a basic definitiion and a basic practical TEST of Ideal Brake Force Distribution, to wit, that you lock the CDL on dry pavement (constant mu), safely, in a straight line and hit the brakes. It's objective, it's physics, and it IS as close to Ideal Brake Force Distribution as practically possible. And it applies to ANY vehicle with AWD and CDL.

Grench: The problem with your supercray example is that you would need to reference some sort of SAE or equivelent test to support your scenario. The biggest issue in regards to PREDICTING handling, is that the guy behind the wheel isn't predictable = radius changes many of them. I have seen very loose attempts in terms of 'steering vs countersteering' and it's possible effects in terms chassis dynamics (mu = constant), but there are very few actual measures associated with these general 'indicators', and I have yet to see a mixed mu presentation in any publication. There is a reason it's tough to find a reference to attempting what you have done. Remember that changing weight distribution in a turn (esp a mixed mu scenario) changes radius without any steering input. Again, you have put forth something pretty far from post #1, but happy to go there in another thread. To post #1 = NA. I would be more curious as to your 3 channel vs 4 channel ABS comment. Why would 4 channel ABS "be better"?

FT41: Normally, we find ourselves in a pretty predictable mu. Wet pavement, dry pavement, snow, gravel, sand. I understand the want to look to mixed mu, but ABS isn't really a mixed mu device, it's not programmed to be. Mechanically, in mixed mu, ABS reduces rear brake force to the wheel with the lowest traction. Again, to the definition and test in post #1 = NA

I personally would like to get agreement on Post #1, instead of jumping too far ahead. I see no post that disagees with Post #1 as presented, only big jumps to conclusions that ABS is better in mixed mu turns in terms of control. I can put on the record I don't summarily agree, but to the definition and test in post #1 = NA

Post 1 has nothing to do with chassis dynamics in turns or mixed mu turns. It's a physics theory and practical FZJ80 test of Ideal Brake Force Distribution. Roiling it beyond that exceeds the scope of Post 1


Thanks for the consideration.

ST

 

[concretejungle]

I just have to get this off my chest...

i have nothing tech to add to this thread, but i at least appreciate sumotoy trying to reach out and supply information to us. But what i see every damn time is people being complete jack-ass to him and trying to break him down and find every flaw in his argument.

get over it yall'.

 

[Romer]

The following words and other's in Post #1 imply your recommend it

"the comparison of ideal (CDL locked) vs stock "

This is how you message comes across to me even if that is not what you intended. Remember, communication depends on what the listener/read understands from your message, not what you meant to say.

I feel based on the other thread and this newer thread along with your statement that locking the CDL is ideal warrents my comment. I again did not say you were wrong, only clarifying to others thats your opinion. You can use the argument that it is not an opinion but physics with someone else. I see it as your opinion based on your interpetation of the data and your understanding of physics.

That is of course my opinion and the laws of physics do not apply to moderation of this forum.

 

[Hayes]

While I wouldn't say that partcipating in a SUMOTOY Tech Quagmire is a pleasant experience, I'm feeling warm and fuzzy this morning, and I'd hate to see things flame out--let alone result in talk of banning.

Alleged hazardous recommendations notwithstanding, these threads are ultimately harmless and moderately stimulating tech for the first seventeen pages or so .

My humble suggestion:
Know and understand what you're getting into when you post in a SUMO thread, and WHEN you start feeling annoyed, bail out for a while.

Hayes

I just have to get this off my chest...

i have nothing tech to add to this thread, but i at least appreciate sumotoy trying to reach out and supply information to us. But what i see every damn time is people being complete jack-ass to him and trying to break him down and find every flaw in his argument.

get over it yall'.

 

[EricG]

The following words and other's in Post #1 imply your recommend it

"the comparison of ideal (CDL locked) vs stock "

This is how you message comes across to me even if that is not what you intended. Remember, communication depends on what the listener/read understands from your message, not what you meant to say.

I feel based on the other thread and this newer thread along with your statement that locking the CDL is ideal warrents my comment. I again did not say you were wrong, only clarifying to others thats your opinion. You can use the argument that it is not an opinion but physics with someone else. I see it as your opinion based on your interpetation of the data and your understanding of physics.

That is of course my opinion and the laws of physics do not apply to moderation of this forum.

It was clear to me in reading the first post that SUMOTOY was suggsting braking with the CDL locked as a test to compare the "ideal" brake force distribution to what the brake proportioning valve provides when the CDL is unlocked. A test I hope to try as soon as I unload some crap from my truck and can find a large, dry, empty parking lot.

While a locked CDL may provide ideal braking for the *test* situation he described,, a locked CDL (and disengaged ABS) is obviously NOT ideal for day to day driving. And SUMOTOY never suggested or advocated that to my knowledge. So somebodies reading comprehension is off.

So - in a probably hopeless attempt to get this thread back on topic - has anybody ever tried the test SUMOTOY proposes? Specifically, as I understand it:

Braking hard (but not sliding or engaging ABS) in a straight line on a level, consistent surface. One run with the CDL locked, and one run with the CDL unlocked.

What to look for is braking distance and how hard the vehicle pitched down in the front.

Has anybody ever played with the brake proportioning valve to see what the effect is? It seems adjusting it might be particularly useful on lifted/re-sprung/armored/drawered trucks.

 

[SUMOTOY]

The following words and other's in Post #1 imply your recommend it

"the comparison of ideal (CDL locked) vs stock " ...

Romer:
... In a straight line comparo with mu as a constant. A stock truck with ABS is deliverd with an open CDL. A CDL locked AWD vehicle in constant mu gives Ideal Brake Force Distribution in a straight line. I give the definition and the test conditions only, and only address post #1 in relation to the thread opinions. There is no 'opinion' of the definition of Ideal Brake Force Distribution.

I can back up Post #1 to a more basic Physics 101 logic tree to bring forward IBFD, but that really goes beyond the scope of 80 technical forum (then moderator moved to chat ). I believe a better direction to pursue is to refine the definition or refine the test in post #1 than ascribing "opinion" to a known physics property of vehicle braking dynamics.

Understanding IBFD was my key and goal in post #1, and there is nothing beyond the described test in post #1 regarding on road CDL driving preference.

My 02., YPMV?

ST

 

[Romer]

Eric - You didn't read this thread then:

https://forum.ih8mud.com/showthread.php?t=127586

Sumo said I should have put the disclaimer in that thread. I eleceted to put it in this one because it is the later topic and is a follow-on.

I will state this again, I am not saying he is wrong, just saying it is his opinion. And because you came in after the first thread and didn't interpret it the same way I did does not mean my comprehension reading is off (Not nice to insult the moderator ) . Different people can interpret different things from the same words. That was how I interpreted what he was saying after reading the other post.

The only point was is for a newbie not to walk away and think the right thing to do is lock the CDL.

 

[SUMOTOY]

While I wouldn't say that partcipating in a SUMOTOY Tech Quagmire is a pleasant experience, I'm feeling warm and fuzzy this morning, and I'd hate to see things flame out--let alone result in talk of banning.

Alleged hazardous recommendations notwithstanding, these threads are ultimately harmless and moderately stimulating tech for the first seventeen pages or so .

My humble suggestion:
Know and understand what you're getting into when you post in a SUMO thread, and WHEN you start feeling annoyed, bail out for a while.

Hayes

... Or, just work through Post #1, and refine or redefine it, not me. I didn't start this thread to move into mix mu, or define any other matrix of vehicle dynamics. I put forth a factoid regarding the basic definition and simple test of IBFD. I want to move onto the definition of ABS select low principle, then onto brake hardware. Then possibly work thru some improvements or identifications of 90 chassis dynamics.

I can work on my followup discussion presentations, but it's tough to move on to more fun stuff, when roiled in a -physics- debate. None of us have time to back this concept up any further, and I don't usually need to when I present this in classroom settings.

My passion is awd vehicle dynamics. I thoroughly enjoy the most nerdy discussion of them, and have enjoyed over the years bantering with design engineers and race car drivers alike. I'd rather share those stories, and share the laughs that come from AWD vehicle control at Steamboat and drivers schools, than addressing very subjective tangental posts to a simple physics concept.

I apologize in advance/hindsight for any perceptions that I'm an expert. I'm just a awd chassis dynamics guy with a lot to learn, and regularly buck mindset to gain understanding. And my best library references are on stained collections of beer napkins with borrowed pencils.

Cheers all

ST

 

[Grench]

Running out of things to agrivate the bees with.

A couple of clarifications here. First any *warning* in relation to post #1 is N/A. No where in -this- thread do I *advocate* suggest or advise anyone to drive around with the CDL locked. What I propose in post #1 is a basic definitiion and a basic practical TEST of Ideal Brake Force Distribution, to wit, that you lock the CDL on dry pavement (constant mu), safely, in a straight line and hit the brakes. It's objective, it's physics, and it IS as close to Ideal Brake Force Distribution as practically possible. And it applies to ANY vehicle with AWD and CDL.

If assumed that the operator (an idiiot like me) can hold and maintain the exact proper pedal pressure through the friction curve, a perfect 100% of the traction available. If at any time that pedal pressure exceedes 100% of the equivalent friction available, the net stopping power drops dramatically as the vehicle slides in a linear vector based on momentum.

Grench: The problem with your supercray example is that you would need to reference some sort of SAE or equivelent test to support your scenario.

No, not really. In the 110% pedal force braking example, I know that any vehicle without ABS is going to lock all 4 wheels and skid uncontrolled in the direction of it's greatest momentum. No units, no formulaes needed. Just simple plain physics of a set of 4 skidding tires.

The biggest issue in regards to PREDICTING handling, is that the guy behind the wheel isn't predictable = radius changes many of them.

Again, not relevant in my 110% example. The person becomes cargo in every version but ABS.

To post #1 = NA. I would be more curious as to your 3 channel vs 4 channel ABS comment. Why would 4 channel ABS "be better"?

It isn't. Channel 3, tire on pavement is better than channel 4, tire on ice. HOWEVER, since the vehicle has ABS, both wheels are still turning at road speed and lateral traction is maintained on channel 3 (dry) giving channel 3 a traction advantage even though it is not prividing linear (forward vector) braking as the ABS is chattering like mad due to the channel 4 (ice) wheel having no resistance. It still holds the vehicle in line BETTER than a locked skidding wheel.

FT41: Normally, we find ourselves in a pretty predictable mu. Wet pavement, dry pavement, snow, gravel, sand. I understand the want to look to mixed mu, but ABS isn't really a mixed mu device, it's not programmed to be. Mechanically, in mixed mu, ABS reduces rear brake force to the wheel with the lowest traction. Again, to the definition and test in post #1 = NA

I could be wrong, but I thought that the rear axle ABS was tied and the front wheels were each independent? At least thats been my seat of the pants feel from it. ABS prevents skidding. Skidding = sliding. Sliding = movement in the direction of the momentum without operator involvement being relevant.

I personally would like to get agreement on Post #1, instead of jumping too far ahead.

Nope. Post 1 Doesn't reflect the real world as it assumes perfect operator control and perfect conditions. I'm not perfect and I don't drive on perfect roads.

Post 1 has nothing to do with chassis dynamics in turns or mixed mu turns. It's a physics theory and practical FZJ80 test of Ideal Brake Force Distribution. Roiling it beyond that exceeds the scope of Post 1

The term 'Ideal' is your downfall here. Try something like, "maximized theoretical braking under theoretical perfect conditions with perfect operator."

My biggest problem with with your statement is that if at any time the operator exceedes 100% of the available braking friction in real world scenarios, control is gone. To me, that is anything BUT ideal.

Give me a straight line clean flat surface and 10 runs and I'll beat the ABS too. So?

 

[SUMOTOY]

Again, not relevant in my 110% example. The person becomes cargo in every version but ABS.

Falacy: ABS scenarios might *allow* better control, it is not inherent, it can actually be worse control. I put forth that in your senario, it's more evident to me that better control would be with NO braking vs ABS. Again, quite a stretch from post 1.

Nope. Post 1 Doesn't reflect the real world as it assumes perfect operator control and perfect conditions. I'm not perfect and I don't drive on perfect roads.

Grench, you have a basic misunderstanding of IBFD with this statement. ALL braking torque in a locked center diff, in a straight line with constant mu, follows weight distribution up to lockup. The operator could touch the brakes or slam the brakes, or do a combination. Same mu isn't a perfect road. It is just a constant COF on 4 tires.

The term 'Ideal' is your downfall here. Try something like, "maximized theoretical braking under theoretical perfect conditions with perfect operator."

No, see above. Brake capacity and Brake Force are variables, not fixed. The amount of pedal force affects capacity, the mu the amount of force to the braking component of vehicle dynamics. Brake Force Distribution can be ideal, and (up to lockup) is *independent* of Pedal Force OR Brake Force OR Brake Capacity. They become *dependent* variables when the CDL is unlocked with or without ABS activation.

My biggest problem with with your statement is that if at any time the operator exceedes 100% of the available braking friction in real world scenarios, control is gone. To me, that is anything BUT ideal.

That is just not true. Lockup = Control can be related. It's not a given. That's a driver input vs Chasis dynamic variable, not a ABS vs non ABS variable.

Give me a straight line clean flat surface and 10 runs and I'll beat the ABS too. So?

I don't think that's necessarily true, nor have I claimed it. What I do claim is that with CDL locked you have F/R IBFD in a straight line up to lockup on a constant mu. ABS (only) under impending lockup is an electronic moderation of brake hardware to raise the effective F/R brake force distribution towards ideal. How far from ideal depends on a lot of factors, including the brake torque capacity of each axle.

A CDL locked on the other hand, takes any and all brake force distribution up to lockup, and allocates the f/r sum of brake torque capacity exactly to the dynamic weight distribution of the vehicle. Doesn't matter what the *capacity* of either axle is, or the loading of the vehicle, or the COG, or the amount of braking force applied by the driver.

I think you need to look at IBFD before lockup, and with applied pressure varying, even in the same stop test, any and all brake force follows weight distribution. I can also provide you some SAE references to how mu is presented. I can *not* provide you with any SAE references to support your claims of directional stability in any given mixed mu matrix.

ST

 

[Grench]

Hmm... Any more bee hives about?

Brake Force Distribution can be ideal, and (up to lockup) is *independent* of Pedal Force OR Brake Force OR Brake Capacity.

That is just not true. Lockup = Control can be related. It's not a given. That's a driver input vs Chasis dynamic variable, not a ABS vs non ABS variable.

I think you need to look at IBFD before lockup, and with applied pressure varying, even in the same stop test, any and all brake force follows weight distribution.

Again, you keep assuming two BIG things.
1. Equal friction on all 4 tires.
2. Perfect operator control to hold brake inputs to near or at 100% of the available friction without going over, i.e. without lockup.

Both assumptions do not apply in the real world except in a very few circumstances that rarely result in death.

A locked (stopped) tire sliding/skidding over a surface is pretty much non-directional. A vehicle where all of the tires are stopped has no directional control and will move in the path of least resistance relative to it's momentum. See also flying sideways off a curve.

People panic. They can't judge road surfaces 60+ times per second and adjust perfectly as they change. They certainly can't do it for axles/wheels independently.

Given these realities, I think that any solution has to include them to be 'ideal'. No, the ABS brakes on an FZJ80 is not ideal. In practice, nothing is. Four wheel independent ABS with the pedal mashed probably comes the closest reliably on mixed surfaces, but we don't have that system.

 

[KliersLC]

So, can we skip ahead to the part where you tell us how to get better braking performance out of our rigs without having the center diff locked up??

X2

All of this is very well and good, and grench brings up some good points, but at times they seem extraneous to what ST is saying.

OTOH, ST, like I said above, show us the practical applications and then if somebody wants to know the why and how, then tell them.

I really could care less about IDFPG or whatever the hell, but if you could tell me how to increase my braking performance with chassis and brake tweaking, then I would be interested.....



Dan

 

[Waggoner5]

What I am trying to figure out is, when has there been an issue with 80 series braking? I follow the forum and I don't think anyone has posted of their brakes not working correctly or not at all. It is not a rally vehicle, just as it is not a rock crawler. I completely removed all traces of ABS because I am old school, not because it didn't work. My truck will lock up all 4 almost simultaneously on wet or dry pavement weighing in at 4991 and having 57-43 bias on 40" tires. No science here, just dumb luck.

 

[SUMOTOY]

Again, you keep assuming two BIG things.
1. Equal friction on all 4 tires.
2. Perfect operator control to hold brake inputs to near or at 100% of the available friction without going over, i.e. without lockup.

Grench: I'm having a tough time getting you to understand.
1. Pick dry pavement, mu of .9. Leave it at not mixed mu conditions. Remember too, in a straight line the back tires follow the exact same surface as the fronts.
2. This is where you lose the concept. You don't have to hold brake input in post #1. Any brake pedal pressures (plural) below lockup Ideal Brake Force Distribution applies with CDL in post 1. Specifically raise and lower your foot pressure on the pedal as you perform the test in post 1, Brake force follows weight distribution always. Exactly the definition of imperfect operator control with IBFD, and no required lockup (Impending lockup is a *requirement* for ABS to attempt electronic IBFD)

Both assumptions do not apply in the real world except in a very few circumstances that rarely result in death.

We can speak to Ideal Brake Force Distribution BEFORE ABS activation as bettter brake control in a straight line. We can speak to the same or better brake control in turns without lockup. I can't speak to your scenario, because it would require a lot more information than you posted. I have a basic disagreement wtih any presentation that in mixed mu, ABS = Vehicle control.

A locked (stopped) tire sliding/skidding over a surface is pretty much non-directional. A vehicle where all of the tires are stopped has no directional control and will move in the path of least resistance relative to it's momentum. See also flying sideways off a curve.

That doesn't at all mean you have ANY vehicle control with ABS activation. It doesn't mean you have ANY vehicle control with no braking whatsoever.

People panic. They can't judge road surfaces 60+ times per second and adjust perfectly as they change. They certainly can't do it for axles/wheels independently.

Grench: Try the experiment in Post #1, and get a feel for what Ideal Brake Force Distribution is. Then take the CDL off and try it again. At the limit of adhesion, guessing as to vehicle dynamics in a mixed mu turn and brake scenario is beyond any definitive conclusion. I understand you *want* to do it, I also understand why no one else in vehicle dynamics engineering even tries.

Given these realities, I think that any solution has to include them to be 'ideal'. No, the ABS brakes on an FZJ80 is not ideal. In practice, nothing is. Four wheel independent ABS with the pedal mashed probably comes the closest reliably on mixed surfaces, but we don't have that system.

Who does? Jumping ahead to 202, 4 Channel ABS systems use select low principle as well. This is an indicator that mixed mu programming only applies to the front brakes (referred to as Front Track mixed Mu programming) The rears are single circuit activated, which means trying to achieve mixed mu ABS - Wheelbase and/or Rear Track programming for control is not yet possible. Minimal rear braking (none if one rear wheel is on ice) means that control is not a ABS component of mixed mu surfaces while turning and braking.

Grench, you need to get a grasp (grip on what is in post 1. Try the experiment, you are getting way ahead of yourself here. To understand constant mu, put the locked CDL brake force at lockup on dry pavement, which tire/s skids first? Try it again 30 feet later on the same surface. Same wheel/s? I predict so.

ST

 

[SUMOTOY]

OTOH, ST, like I said above, show us the practical applications and then if somebody wants to know the why and how, then tell them.

I really could care less about IDFPG or whatever the hell, but if you could tell me how to increase my braking performance with chassis and brake tweaking, then I would be interested.....

Dan

.... Always those that want to jump ahead to the answers. Dan, try the experiment in post #1. What do you conclude doing it? Forget ABS, I conclude that the stock proportioning valve in the 80 just sucks. It's the same design as the one in my 4R, and that one sucked.

The definition and the exercise in post 1 is to help each *individual* 80 owner (regardless of mods or loading) to understand what IBFD is.

What variables would affect brake force distribution? Well if we know that with CDL locked, Ideal Brake Force Distribution follows weight distribution under braking (including in ABS *activated* 80's) , the big factors to an easy answer revolves around contolling the amount of weight transfer:
* COG = lift kit
* Spring rate
* Shock rate
* Airbags (what I did to address weight shift)
* Static weight distribution
* Rear proportioning valve pressure curve
* Over run brake force (where does the excess brake force of the prop valve go? - on my 4R it returned to the right front brake line!)
* Tire pressure
* Brake force (big brakes, big rotors, big pads)

Given the SUV market we live in, the variables are much greater from all the add ons than we normally see in street cars. This means that summary 'easy' answers may be much tougher to find. The easiest of the mods is to address weight shift under braking, that will help all 80 trucks, the closer to ideal weight distribution under braking, the closer to ideal brake force you can achieve for given hardware.

What's much tougher to give easy answers to is an individual truck. I have seen hundreds of mods on this forum that couldn't put ABS and vehicle control further apart. COG is a major component of vehicle control in ANY avoidance maneuver. It's not comparing 80 to another 80, it's comparing your 80 in street trim, to your 80 in full battle regalia loaded street/offroad trim.

For that, the answers are much tougher, and would require a disclaimer IMO. I've done a lot of hardware changes over the years to braking systems. In street cars where COG is low and constant, GVWR is relatively low, and street tires are the norm, it's a bit easier.

MY answer? I say reduce the amount of weight transfer under braking is probably the best performance gain for the 80 right now. As I haven't looked as far into the 80 hardware as I did my 4R, suggesting alternative hardware hasn't been high on my priority list. Maybe make sure your brake proportioning valve is actually proportioning?

ST

 

[Buckru]

.... Always those that want to jump ahead to the answers. Dan, try the experiment in post #1. What do you conclude doing it? Forget ABS, I conclude that the stock proportioning valve in the 80 just sucks. It's the same design as the one in my 4R, and that one sucked.

The definition and the exercise in post 1 is to help each *individual* 80 owner (regardless of mods or loading) to understand what IBFD is.

What variables would affect brake force distribution? Well if we know that with CDL locked, Ideal Brake Force Distribution follows weight distribution under braking (including in ABS *activated* 80's) , the big factors to an easy answer revolves around contolling the amount of weight transfer:
* COG = lift kit
* Spring rate
* Shock rate
* Airbags (what I did to address weight shift)
* Static weight distribution
* Rear proportioning valve pressure curve
* Over run brake force (where does the excess brake force of the prop valve go? - on my 4R it returned to the right front brake line!)
* Tire pressure
* Brake force (big brakes, big rotors, big pads)

Given the SUV market we live in, the variables are much greater from all the add ons than we normally see in street cars. This means that summary 'easy' answers may be much tougher to find. The easiest of the mods is to address weight shift under braking, that will help all 80 trucks, the closer to ideal weight distribution under braking, the closer to ideal brake force you can achieve for given hardware.

What's much tougher to give easy answers to is an individual truck. I have seen hundreds of mods on this forum that couldn't put ABS and vehicle control further apart. COG is a major component of vehicle control in ANY avoidance maneuver. It's not comparing 80 to another 80, it's comparing your 80 in street trim, to your 80 in full battle regalia loaded street/offroad trim.

For that, the answers are much tougher, and would require a disclaimer IMO. I've done a lot of hardware changes over the years to braking systems. In street cars where COG is low and constant, GVWR is relatively low, and street tires are the norm, it's a bit easier.

MY answer? I say reduce the amount of weight transfer under braking is probably the best performance gain for the 80 right now. As I haven't looked as far into the 80 hardware as I did my 4R, suggesting alternative hardware hasn't been high on my priority list. Maybe make sure your brake proportioning valve is actually proportioning?

ST

Thats the first thing I've read from you that I completely understand. Now, how do I check to make sure my proportioning valve is actually proportioning?


Buck

 

[Romer]

Scott,
May I make a suggestion (OK guess I will)

Can you at a typical driver level explain the brake system, ABS vs non ABS and the proportioning valve without any equations or acronyms. I think you would get less flack if first you got your audience to understand the system you are discussing, then your theory and then why you feel that way. Then I think you can have the discussion you are looking for.

I'm like Buck, I like the answer and then like to know why. It helps to understand where you are going to put the pieces together.

It's kind of interesting (Tangent) if any of you have taken the Myers Briggs test. I am an ISTJ and while only 6% of the population are ISTJ's, 45% of managers in large companies are. We are assertive, impatient, want to get to the bottom line and want the concrete facts and not the abstract, I want enough data to quickly come to a decision and then move on to the next probem. My wife is an ISFJ. Instead of telling me she wants me to go to the store and get milk, she goes into a 5 minute story on why we are out of milk where my eyes glaze over and she says "are you listening".
Turns out I got this book at one of my Management training courses called "Type Talk at work" it describes how different people are wired and how their interactions are a result of the way they are wired. My wife and I looked up the section talking about interactions between ISTJ's and ISFJ's and it fit us to a tee. We have learned to better communicate with each other based on what we learned here.

The reason for this long tangent is that some of us are wired differently and hear things in a different way then is intended and don't follow along well with the flow of information that seems obvious to others.

So, I propose you try a different tact and try again without the physics and the math. First explain the brake system (Orient your audience), Tell them your Theory, Explain why you think it's true and give a high level summary for "idiots". This is actually the format I was taught to create reports and technical papers to not lose your audience.

Just a suggestion

 

[Jason Andrews]

mu (greek letter) = coefficient of friction (commonly, and definitely in this thread).



So... as long as I'm here:

WHO HERE OTHER THAN SUMOTOY HAS TRIED DRIVING THEIR 80 AROUND TOWN WITH THE CENTER DIFF. LOCKED??

From a summary reading of this and related threads, all I've seen is people saying, "Well, I haven't tried it, but that's stupid." I'm not saying it's NOT stupid; I'm just saying it'd be nice if someone else gave it a try to see whether his handling claims are BS or not, rather than just claiming they are. (Yes, I'm volunteering to be a guinea pig if needed...)

Curtis

Thanks Curtis,

YES! I do drive with CDL all the time when its snow packed roads at any speed.

I am right with SUMO with driving it on road with snow deep enough that your tires are not touching the road. I would NEVER lock it if they were touching the roadway.

1) Having bigger tires could make a difference in our opinions. My rig will lock up easily and slide sideways when making turns without it. NOT THE OPPOSITE like you would think!!!!!



2) IMHO it is better described as gear braking like downshifting for down hills. Not better brake proportioning which I have said before. On super steep hills and snowy roads I like the control that the driveline provides and will trust it any day over brakes!!

Just because everyone Roasted SUMO on another issue this summer doesnt mean he is all wrong.

Seems like everyone is assuming the CDL reacts like lock the front or rear diff. It will not break tires free like that.

Example: 40's on a 4"lift??? You are an idiot that will never work. Think for yourself. If you dont have snow, are not worried about your control, or have never experimented. . . Do us a favor and keep your repeditive comments to yourself

 

[Waggoner5]

Example: 40's on a 4"lift??? You are an idiot that will never work. Think for yourself. If you dont have snow, are not worried about your control, or have never experimented. . . Do us a favor and keep your repeditive comments to yourself

Didn't get it.

 

[Jason Andrews]

Didn't get it.

Its the ROTW and I love it!! . I am not bashing his shi! I am saying people say that 40's wont fit on 4".....the same as they are saying CDL is stupid on roads.

They dont know, the ROTW is proving many people wrong. It can work!!! Try it before just listening to "someone" who says it cant/shouldnt be done!