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Annual Snow Tire Test thread - Page 14

post #391 of 403

ABS while it does increase your stopping distance, it does allow you to steer the car better, of course, you need winter tire traction to steer.

 

Threshold braking is shorter, but...  in the event you need to steer around an obstacle (like another car), or the road curves.... chances of avoiding it is worse.

post #392 of 403
Thread Starter 
Quote:
Originally Posted by tanscrazydaisy View Post
 

ABS while it does increase your stopping distance, it does allow you to steer the car better, of course, you need winter tire traction to steer.

 

Threshold braking is shorter, but...  in the event you need to steer around an obstacle (like another car), or the road curves.... chances of avoiding it is worse.

Apply brake to shift weight to front tires, remove brake as you turn wheel to swerve around obstacle, so that ALL available traction (included added temporary traction due to weight shift) is used to swerve.   Come to think of it, removing your foot from the brake works even if you have the ABS on.  Relying on the ABS to prevent lock up and not taking your foot off the brake when you swerve does not give you full swerving power.

post #393 of 403
Quote:
Originally Posted by pete View Post

hum, on pondering one can defeat most ABS by pulling the fuse, not that I'm advocating but should one wish to play in a lot ... 

of course, as I'm not advocating I would also suggest checking with smart folks to ensure nothing detrimental is a result of a pulled fuse : )

One of the nice things about 4x4's once upon a time, or at least some of them, is lock the center diff and it turns ABS off. My Land Cruiser does that, and it is really nice to not have ABS at the point conditions are more severe. Not sure if they still do that since you really, really do not want ABS off-road.

On a newer vehicle, traction control is built upon the ABS platform (electronic brake modulation), and I would guess those things are electronically married at this point. Although I don't know if the systems use different sensors at the wheel hub. I suspect you'd be sent to bed without dinner if you cut out the ABS sensors given today's electronic sensor standard...
post #394 of 403
Quote:
Originally Posted by Ghost View Post
 

Apply brake to shift weight to front tires, remove brake as you turn wheel to swerve around obstacle, so that ALL available traction (included added temporary traction due to weight shift) is used to swerve.   Come to think of it, removing your foot from the brake works even if you have the ABS on.  Relying on the ABS to prevent lock up and not taking your foot off the brake when you swerve does not give you full swerving power.

Easier say than done.  Steering and slowing down with threshold braking and steering in between braking, is quite tough to do.

 

In the snow/ice, it doesn't take much to lock the wheel and you don't have much in terms of weight transfer to work with, to pivot the car.  Unless maybe if you had extra traction from studded tires in those scenarios. E-brake turns is easier to do, but you need to get experience with e- brake turns to control the turn properly.  (if you have electronic e- brakes.... forget about e-brake turns... come to think of it, the foot operated e-brakes would be challenging also).

 

WHen you have ABS, and it's pumping the brakes, there's no point of releasing the brake to steer.  That's the advantage of ABS brakes these days.... you have trade-offs to work with.

post #395 of 403
Thread Starter 
Quote:
Originally Posted by tanscrazydaisy View Post
 
Quote:
Originally Posted by Ghost View Post
 

Apply brake to shift weight to front tires, remove brake as you turn wheel to swerve around obstacle, so that ALL available traction (included added temporary traction due to weight shift) is used to swerve.   Come to think of it, removing your foot from the brake works even if you have the ABS on.  Relying on the ABS to prevent lock up and not taking your foot off the brake when you swerve does not give you full swerving power.

Easier say than done.  Steering and slowing down with threshold braking and steering in between braking, is quite tough to do.

 

In the snow/ice, it doesn't take much to lock the wheel and you don't have much in terms of weight transfer to work with, to pivot the car.  Unless maybe if you had extra traction from studded tires in those scenarios. E-brake turns is easier to do, but you need to get experience with e- brake turns to control the turn properly.  (if you have electronic e- brakes.... forget about e-brake turns... come to think of it, the foot operated e-brakes would be challenging also).

 

WHen you have ABS, and it's pumping the brakes, there's no point of releasing the brake to steer.  That's the advantage of ABS brakes these days.... you have trade-offs to work with.


If your ABS is pumping the brakes xxx times per second, some of your traction is being used to stop.  That traction is not available to turn.  You can turn more with your foot completely off the brake pedal.  

 

Just because your tire won't lock up does not mean it won't skid sideways.  It is best to use all the traction you can when you NEED to turn. 

 

Most cars I've had had a very touchy emergency brake, mind you most of 'em had drum brakes on the rear too (pivot point of the shoe makes them prone to grab).  I would not recommend e-brake turns to swerve around obstacle in any case.

post #396 of 403
Quote:
Originally Posted by Ghost View Post
 


If your ABS is pumping the brakes xxx times per second, some of your traction is being used to stop.  That traction is not available to turn.  You can turn more with your foot completely off the brake pedal. 

 

Just because your tire won't lock up does not mean it won't skid sideways.  It is best to use all the traction you can when you NEED to turn.

 

Most cars I've had had a very touchy emergency brake, mind you most of 'em had drum brakes on the rear too (pivot point of the shoe makes them prone to grab).  I would not recommend e-brake turns to swerve around obstacle in any case.

Adding in these days, (and continue the discussion with stability control), the stability control can do a better job then no-braking, as it can selective brake a wheel (even better if the ABS system is 4-channel), to correct a skid.

 

Skidding is from having a traction differential, front to rear, side to side.  You can drive in a straight line, and start to skid without even touching the brakes in the snow.

 

ABS computers can react faster than our brain and foot, so during the fraction of the second it's not braking, you have your traction you NEED to turn.

post #397 of 403
Thread Starter 
Quote:
Originally Posted by tanscrazydaisy View Post
 
Quote:
Originally Posted by Ghost View Post
 


If your ABS is pumping the brakes xxx times per second, some of your traction is being used to stop.  That traction is not available to turn.  You can turn more with your foot completely off the brake pedal. 

 

Just because your tire won't lock up does not mean it won't skid sideways.  It is best to use all the traction you can when you NEED to turn.

 

Most cars I've had had a very touchy emergency brake, mind you most of 'em had drum brakes on the rear too (pivot point of the shoe makes them prone to grab).  I would not recommend e-brake turns to swerve around obstacle in any case.

Adding in these days, (and continue the discussion with stability control), the stability control can do a better job then no-braking, as it can selective brake a wheel (even better if the ABS system is 4-channel), to correct a skid.

 

Skidding is from having a traction differential, front to rear, side to side.  You can drive in a straight line, and start to skid without even touching the brakes in the snow.

 

ABS computers can react faster than our brain and foot, so during the fraction of the second it's not braking, you have your traction you NEED to turn.


Computers cannot overcome the laws of physics.  Best not try to stop and turn at the same time if what you really want to do is turn.

post #398 of 403
Anyone tried the Yokohama ice guard IG51v?
post #399 of 403
Thread Starter 
Quote:
Originally Posted by ScotsSkier View Post

Anyone tried the Yokohama ice guard IG51v?


Haven't tried them, but they were reviewed by the APA here  http://www.apa.ca/WinterTires2014-SUVs.asp

post #400 of 403
Quote:
Originally Posted by tanscrazydaisy View Post

Quote:
Originally Posted by Ghost View Post

 


If your ABS is pumping the brakes xxx times per second, some of your traction is being used to stop.  That traction is not available to turn.  You can turn more with your foot completely off the brake pedal. 

Just because your tire won't lock up does not mean it won't skid sideways.  It is best to use all the traction you can when you NEED to turn.

Most cars I've had had a very touchy emergency brake, mind you most of 'em had drum brakes on the rear too (pivot point of the shoe makes them prone to grab).  I would not recommend e-brake turns to swerve around obstacle in any case.
Adding in these days, (and continue the discussion with stability control), the stability control can do a better job then no-braking, as it can selective brake a wheel (even better if the ABS system is 4-channel), to correct a skid.

Skidding is from having a traction differential, front to rear, side to side.  You can drive in a straight line, and start to skid without even touching the brakes in the snow.

ABS computers can react faster than our brain and foot, so during the fraction of the second it's not braking, you have your traction you NEED to turn.

Until they fail, and they act up more than you think. I like it better that I have control, rely on the car and you get sloppy when it matters most along with the fact that you exercise less caution when required.
post #401 of 403
Quote:
Originally Posted by tanscrazydaisy View Post

Adding in these days, (and continue the discussion with stability control), the stability control can do a better job then no-braking, as it can selective brake a wheel (even better if the ABS system is 4-channel), to correct a skid.

Skidding is from having a traction differential, front to rear, side to side.  You can drive in a straight line, and start to skid without even touching the brakes in the snow.

ABS computers can react faster than our brain and foot, so during the fraction of the second it's not braking, you have your traction you NEED to turn.

This gets back to tire designs integrating with electronic systems. A really good tire should gain traction as it slips by packing snow in the right way, even just small amounts on icy surfaces. If you have that type of tire, ABS actually defeats the traction of the tire.

When a tire is designed to work with ABS, getting back to breakaway threshold, once it goes the ABS system is now attempting to address traction that is not being quickly regained. This is why I won't run studless can winter tires. Too many breakaway failures, ABS happily pumping away.

I know you've seen me post this before that I took last year, comparing a 2007 Nissan Quest with studded winter tires and 1995 Land Cruiser. It is slick - the Quest could barely get back up this hill (I won't post that vid again). First is the Quest, and you can tell when ABS engages (it slips immediately). Second is the Cruiser, and definitely obvious when ABS engages, but admittedly that is also a not so tight recirculating ball steering system.

After that it is all Cruiser, ABS off, mashing the throttle and the brakes. Look at the tire track as I back up at the very end. The tire has consolidated a little bit of powder on top of the ice, and what happens from the driver's perspective is the slide slows, and them comes to a quick reassuring thunk once the tire pulls in enough of that powder surface. The winter tires never do that. The studs create about an equal level of bite, but without them all of the studless winter tires I have used will more or less keep on going until friction, gradient, or grippier conditions prevail.

You can steer in a controlled slide with a little bit of throttle input when the vehicle is actually coming to a stop. I get that this is too much of an ask for how we train drivers, but I don't think last drivers will steer around an accelerating ABS engagement, either. So it is either a tire designed for traction in the absence of electronic controls or studs for me, because those are the only two things that overcome threshold breakaway problems in modern systems.
post #402 of 403
For what I mean about a tire designed for traction in the absence of electronic systems, here's a Contour POV aimed directly at the tire.

First part is soapy snow on dirt, then packed powder and icy sections on dirt, then mixed road conditions. It is really interesting to see the tire go through transitions of holding snow and shedding it as conditions change. Center diff is locked, which is akin to having stability controls at speed.

The last bit I head up a 7% or so grade to a cul-de-sac with about 10" deep wind blown snow on the passenger side but only 2-3" on the driver's side. Gun it coming through the cul-de-sac, and accelerate downhill with the deeper snow on driver's side. I stop as fast as I can on the downhill as if I had a stop sign at that intersection (I don't). Not pumping brakes here, just working threshold tire feedback with brake pressure @ about 25 mph, 7% grade. ABS is off here.

Obviously people can draw their own conclusions as to what truly constitutes good traction and predictable performance. ABS will take away the ability to do what you see in that vid, which includes an intentional shortest possible distance slide at the end.
post #403 of 403
ABS doesn't engage until it detects lock or near lock of brakes via the wheel speed sensor vs the actual speed.

When you drive in the summer time, you don't see the ABS kick in often due to increased friction between the asphalt/concrete and your tire.

I know studded tires work better going down a packed snow hill... Not everyone lives in an area that allows for studded tires.


Sent from my iPhone. There may be horrible grammar and misspelling involved
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