However 35's have a longer contact patch fore/aft than the stock tires since it's a taller tire. So why is a stock tire better then in this regard?
80 in ice & snow + question re CDL
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However 35's have a longer contact patch fore/aft than the stock tires since it's a taller tire. So why is a stock tire better then in this regard?
Wow, quite a diversion! To the original post, there are many reasons why you 'feel' better with the CDL on. I'm always intrigued by Vehicle Dynamics explanations vs what is happening. This diverged into 'run ABS' mode, but I expect that.
Tires slip all the time, that in and of itself doesn't make CDL on less safe or more safe. Maximum Tire slip angle to a given vehicle application *VARIES* between all tire brands, sizes and compounds. This is what makes some tires better at snow, rain or dry duty than others.
As a matter of course, I run CDL-on most of the time. I enjoy the smoother handling, better braking, and overall performance gain. Debating ABS vs non ABS capabilities really has been the focus here, when in actuality it's CDL-on VS CDL-off modes that dictate the difference. At best ABS *might* allow better steering, a big jump to say that's better control, as I believe that to be a driver function IME. As I've said many times before Tires and COG (read: lift kits) have more effect on handling and control than CDL mode.
In terms of safety, I can look at pics of mods to these trucks that change a lot of how the 80 handles, offsetting ABS safety gains, with COG, weight, weight distribution, and tire concerns. The best offroad tires are far from the best on road tires. We all accept compromises to safety, Off Road SUV's the most of all. I chuckle a bit that locking the CDL causes such an uproar from a safety standpoint. I can look at 100lbs of winch hanging off the front of a lifted 80 with mudders and think 'avoidance manuever' isn't close to an ABS variable.
ST
Tires slip all the time, that in and of itself doesn't make CDL on less safe or more safe. Maximum Tire slip angle to a given vehicle application *VARIES* between all tire brands, sizes and compounds. This is what makes some tires better at snow, rain or dry duty than others.
As a matter of course, I run CDL-on most of the time. I enjoy the smoother handling, better braking, and overall performance gain. Debating ABS vs non ABS capabilities really has been the focus here, when in actuality it's CDL-on VS CDL-off modes that dictate the difference. At best ABS *might* allow better steering, a big jump to say that's better control, as I believe that to be a driver function IME. As I've said many times before Tires and COG (read: lift kits) have more effect on handling and control than CDL mode.
In terms of safety, I can look at pics of mods to these trucks that change a lot of how the 80 handles, offsetting ABS safety gains, with COG, weight, weight distribution, and tire concerns. The best offroad tires are far from the best on road tires. We all accept compromises to safety, Off Road SUV's the most of all. I chuckle a bit that locking the CDL causes such an uproar from a safety standpoint. I can look at 100lbs of winch hanging off the front of a lifted 80 with mudders and think 'avoidance manuever' isn't close to an ABS variable.
ST
Statistics without context are pretty dangerous -
http://www.babcox.com/editorial/cm/cm50030.htm
"A couple of years ago, the Highway Loss Data Institute (HLDI) published a controversial study that said ABS wasn't making much of a difference in reducing accidents or fatalities. The study reviewed 1,000 fatal crashes that occurred from 1986 to 1995. When HLDI researchers analyzed the data, they found people actually had a higher risk of dying in an accident if their vehicle was equipped with ABS brakes! But the report also found that multi-vehicle fatal crashes on wet roads were actually 24 percent lower for ABS-equipped cars, and that ABS-equipped cars killed 27 percent fewer pedestrians and bicyclists. But these reductions were offset by a 28 percent higher fatality rate involving accidents where an ABS-equipped vehicle ran off the road and rolled over.
The National Highway Traffic Safety Administration (NHTSA) said the HLDI report findings may be explained by several factors. Drivers who are unfamiliar with ABS may not keep their foot on the brake or may pump the pedal during a panic stop, reducing the effectiveness of the ABS system and increasing the stopping distance. ABS may also give some drivers a false sense of security, possibly encouraging them to drive more aggressively."
NaterGator
On Gilligan's Island
Not to mention cars have been getting increasingly more powerful... high top speeds, high acceleration, high limits of adhesion. All make for more serious accidents.
".... May be explained by several factors" is not yet in the updated studies, those are 'pending'. What the old studies show is that they could find no correlation to any single factor, and they tested for all of the above in 1996 study actually.
I read that to mean, it *may* or *may not* be explained by anything, but quite possibly just that ABS *allowing the ability to have* Steering Control <not equal to> Vehicle Control. That's a driver dependent variable.
ST
ST
ummmmm...
Could we take a few steps back, back past the fighting, and try to help this dumb old broad out, please?
I'd like to better undersand a few things.
Mine is a 1992 FJ80. ie: No ABS (and no lockers, btw). Just the CDL.
I have never used the CDL except for use during Katrina. I used it then, quite a bit... never before, and not since. (to get up and down muddy rain-washed-out hills of turf -- towing other vehicles out of the mud where they'd become stuck, hauling people and belongings to drier ground & safety, and bringing Rescue people & supplies in)
I live in northern NJ, and am not too likely to see deep snow this year. (God willing)
Most of what I'll drive in this winter is probably several inches of heavy, wet snow over (and hiding underneath it) some hardpack and/or semi-frozen slush and/or ice. I will be on (horribly maintained) paved city streets. Streets which are as likely as not to NOT have been salted or sanded. Or even plowed properly.
Given these conditions and that I drive on ATs, and have no ABS or lockers...
I am... or I am NOT... better off using CDL, please? And under which snow/winter conditions ought I to use CDL? (if any)
Thanks for clarifying, folks.
Could we take a few steps back, back past the fighting, and try to help this dumb old broad out, please?
I'd like to better undersand a few things.
Mine is a 1992 FJ80. ie: No ABS (and no lockers, btw). Just the CDL.
I have never used the CDL except for use during Katrina. I used it then, quite a bit... never before, and not since. (to get up and down muddy rain-washed-out hills of turf -- towing other vehicles out of the mud where they'd become stuck, hauling people and belongings to drier ground & safety, and bringing Rescue people & supplies in)
I live in northern NJ, and am not too likely to see deep snow this year. (God willing)
Most of what I'll drive in this winter is probably several inches of heavy, wet snow over (and hiding underneath it) some hardpack and/or semi-frozen slush and/or ice. I will be on (horribly maintained) paved city streets. Streets which are as likely as not to NOT have been salted or sanded. Or even plowed properly.
Given these conditions and that I drive on ATs, and have no ABS or lockers...
I am... or I am NOT... better off using CDL, please? And under which snow/winter conditions ought I to use CDL? (if any)
Thanks for clarifying, folks.
That line is getting old: "ABS <not equal to> vehicle control", yeah steering wheels, tires and brakes do not equal vehicle control either but without them you wouldn't have much control. You've worn that one out almost as much as "BTDT".
Given these conditions and that I drive on ATs, and have no ABS or lockers...
I am... or I am NOT... better off using CDL, please? And under which snow/winter conditions ought I to use CDL? (if any)
Thanks for clarifying, folks.
It sounds like your use of it is appropriate. The most reasonable non techy answer was probably my first - I'll paraphrase
I run CDL off on the hwy in ice and snow. Steers much better. When you lock the CDL the vehicle is going to 'push' in corners - as in it will want to keep going straight. If it is slick enough that you can't get going, like your Katrinia experience, that's the right time to use CDL. And if you are in slippery enough conditions to use the CDL, you shouldn't be running at highway speeds.
If you still have your factory owners manual - it should say when to use it and when not to, and I'm actually quite curious as to what it says. Toyota made the deision on post '93 trucks for us. The decision they made was that if you need the traction of CDL, you shouldn't be going any faster than you can in lowrange - as that's the only time the CDL is enguaged on post '93 trucks unless you modify it from the way the dealer delivered it.
I actually use it correctly? Quite by accident?
Wow.
Since last night's post, I had the opportunity to do a bit of experimentation on our icy and snowy roads in the wee hours. Had to take my 18-yr-old foster son to the hospital emergency room. Took the opportunity to test out driving conditions and my FJ80's handling with playing a bit with the CDL switch on and off, 'feeling' it, and taking mental notes.
The road conditions: Urban city streets with minimal amount of plowing done (and none as recent as the latest snowfall), no salt or sand, and it was still snowing. It was all hard ice with fresh powder falling on it. Very slick conditions.
Drove no more than about 25mph speed. Maybe a tad more on Central Avenue. (a major street here)
On straight street (lights all out/non-working, so no stopping, but slowed at each block to see if any vehicles about to try to enter intersections), I preferred the handling of my 80 with the CDL on. By far.
Tried making on right-hand and one left-hand turn with CDL on. After the right turn, I decided I didn't like turning with the CDL on AT ALL. (but gave it one more CAREFUL try on a left turn, anyway, for experimentation purposes)
After that, I hit the switch (off for turns, on for straight driving).
The one time I did have to come to full stop (to let a police B&W cross Central Ave ahead of me), CDL was engaged. Had little trouble getting started right off. (unlike the idiot in a Ram next to me, who spun one of his rear wheels, and spun his pick-up right around by about 70 degrees.
)Soft touch on the gas pedal, dude
Y'know... think I'll go on out to the garage, and grab the manual... and read. I'll be back shortly to post what it says.
hummmmm
Walking Eagle: The following is verbatim quote, taken directly from my (rig's) owner's manual regarding CDL. (pps 42-43)
(I added the first and last parts in the interests of completeness; I am quite sure you need neither to find out where the switch is, nor what the daskboard light warning looks like... nor, for that matter, instructions on how to shift the lever in and out of the 4WD ranges. But one never knows who else might or might not...)
Early in the book, it shows the dashboard, and labels the switch. (right next to the hazard lights switch, of course)
Under Four-wheel drive system (mid book) it says:
(a) Four-wheel drive control lever and center differential lock button
[picture/diagram of the CDL push button, of the dashboard indicator light, and the the range shift (H-N-L range shifter)]
The four-wheel drive control lever and center differential lock button select one of the transfer and center differential modes below by the positions.
The "H" position of the four-wheel-drive control lever provides either lock or unlock mode of the center differential depending on the center differential lock button position.
The indicator light tells when the differential lock is engaged. Note that the differential is not still locked as long as the indicator light remains off.
"H" (unlock): High Range, center differential unlocked
Use this for all types of driving on normal roads, from dry, hard-surfaced roads to wet, icy, or snow-covered roads. This position gives greater economy , quitest ride, least wear and better vehicle control.
"H" (lock): High Range, center differential locked
Use this for greater traction when you experience loss of power, such as wheel slipping, in the "H" (unlock) mode.
"N": Neutral
No power is delivered to the hweels. Use this position only for operating a winch or other equipment. The vehicle must be stopped.
"L": Low range, center differential unlocked
Use this for maximum power and traction. Use "L" for hard pulling in situations the vehicle cannot negotiate even in the "H" (lock) mode.
(b) Shifting procedure
Shifting between "H" (unlock) and "H" (lock)
To shift between unlock and lock modes in "H", push the center differential lock button.
Shifting between "H" and "L"
To shift between "H" and "L", stop the vehicle, put the transmission into "P" or "N" and move the four-wheel drive control lever. Never move the four-wheel drive control lever if wheels are slipping. Stop the slipping or spinning before shifting.
Walking Eagle: The following is verbatim quote, taken directly from my (rig's) owner's manual regarding CDL. (pps 42-43)
(I added the first and last parts in the interests of completeness; I am quite sure you need neither to find out where the switch is, nor what the daskboard light warning looks like... nor, for that matter, instructions on how to shift the lever in and out of the 4WD ranges. But one never knows who else might or might not...)
Early in the book, it shows the dashboard, and labels the switch. (right next to the hazard lights switch, of course)
Under Four-wheel drive system (mid book) it says:
(a) Four-wheel drive control lever and center differential lock button
[picture/diagram of the CDL push button, of the dashboard indicator light, and the the range shift (H-N-L range shifter)]
The four-wheel drive control lever and center differential lock button select one of the transfer and center differential modes below by the positions.
The "H" position of the four-wheel-drive control lever provides either lock or unlock mode of the center differential depending on the center differential lock button position.
The indicator light tells when the differential lock is engaged. Note that the differential is not still locked as long as the indicator light remains off.
"H" (unlock): High Range, center differential unlocked
Use this for all types of driving on normal roads, from dry, hard-surfaced roads to wet, icy, or snow-covered roads. This position gives greater economy , quitest ride, least wear and better vehicle control.
"H" (lock): High Range, center differential locked
Use this for greater traction when you experience loss of power, such as wheel slipping, in the "H" (unlock) mode.
"N": Neutral
No power is delivered to the hweels. Use this position only for operating a winch or other equipment. The vehicle must be stopped.
"L": Low range, center differential unlocked
Use this for maximum power and traction. Use "L" for hard pulling in situations the vehicle cannot negotiate even in the "H" (lock) mode.
(b) Shifting procedure
Shifting between "H" (unlock) and "H" (lock)
To shift between unlock and lock modes in "H", push the center differential lock button.
Shifting between "H" and "L"
To shift between "H" and "L", stop the vehicle, put the transmission into "P" or "N" and move the four-wheel drive control lever. Never move the four-wheel drive control lever if wheels are slipping. Stop the slipping or spinning before shifting.
Yep, sounds pretty much like you're using it exactly as Toyota intended.
.... Supported by the owners manual?
1994 FZJ80 PP 106
"Even if the anti-lock braking system is in operation full stability of the vehicle cannot be maintained for certain slippery road conditions or high speed driving when cornering."
Then further down
"Compared to vehicles not fitted with an anti-lock brake system, you vehicle requires a longer stopping distance in the following cases:
* Driving on rough, gravel, or snow-covered roads
* Driving with tire chains installed
* Driving on roads where the road surface is pitted or has other differences in surface height"
I belive the last is in regards to crowned roads. Unfortunately for FZJ80 owners, the only way to gain advantage is to add the CDL switch or add an ABS off switch.
It might be old, but toyota uses it, even to this day. Ck out the Stability Control and Traction control systems on the toyota website. The warning is the same. Vehicle control is a driver dependent variable, not an ABS dictated one.
ST
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Toyota gives no *warning* to not use CDL on dry pavement. They give specific instructions on the FRONT and REAR differential locks however:
(orange print caution note)
"Caution: Do not use the front and rear differential locks in the conditions other than above. Large steering effort and careful cornering control will be required. Especially the use of the front differential lock in additon to the rear will result in extremely difficult steering control and may cause the vehicle to spin during acceleration or engine braking."
Seems to suport the chart on differential locking vs control. There is no warning as to using the center differential AT ANY TIME, other than not to attempt locking if the wheels are spinning.
I believe the manual is pretty clear that locking CDL does not compromise safety of steering control. I say don't 'make one up', the owners manual doesn't support the statement.
ST
Sumo, you realize that '93-97 that had optional front and rear lockers DID NOT come from the factory with the CDL, and therefore YOUR manual HAS NO REASON TO MENTION IT! That's why it's so nice to have 92LC_good2go's info. from her manual! She's been nice enough to post it for us, try reading it. I'd place a heafty wager that Had the '93-97's had the CDL, they also would have had the same wording. No need for it the way it comes from the factory, as if you're in 4 low, the only place the factory settings put CDL on, you're obviously not at hwy speeds.
Everyone but you seems to understand that CDL on dry pavement is not good for the vehicle. That's why pretty much every 'standard' 4wd says NOT to use 4wd on dry pavement. It creates excessive understeer on dry pavement, and although engineers stay on the safe side with mild understeer (at least since the Corvair insident), excessive understeer is NOT a good thing. The other, more obvious reason not to use it on dry pavement is it binds up the drivetrain, putting undue stress on it, and wears your tires quicker.
Think there might be a reason VW stopped using Syncro and went to 4-motion? Think there might be a reason BMW shelved the system from the 325ix of the 80's, and uses a AWD approach now?
When I get home tomorrow, I'll have to post my 98 LX470 owners manual which mentions not using the CDL switch (it has one stock) on normal driving surfaces, to prevent damage.
ABS does <not equal control>, just like brakes and steering wheels and tires do <not equal control>, they a are a part of the equation for a driver controling a vehicle. Besides that, longer stopping distance does not automatically negate driver control, especially if there is still some steering ability which would be absent if the tires were locked. Try again.
What are these things you speak of... (Ice & Snow)?
Cause they don't ave a longer contact patch fore/aft than stock tires. They're taller yes, and have more fore/aft area total, but the contact patch is only the part that is touching the ground. 35's are pretty much all wider than stock (usually about 12.5" with some tall narrow exceptions). The area of the contact patch is going to be the same if you have 35psi in each tire, but since the stock tire is narrower, that area will be narrower and longer, and the 35's will be wider and shorter. Make sense?
Sumotoy, would you drive around all summer in a part time 4x4 with it in 4hi?
Cuz thats what you are saying......
Cuz thats what you are saying......
Yes I get it now, however in that regards only the width matters as far as decreasing the fore/aft contact patch. If there was a 35" tire in a 275 width the contact patch would be the same as stock. Yes?
