Winter video: why is ABS so bad at stopping?
#1
12-17-2013, 01:39 PM
Winter video: why is ABS so bad at stopping?
(Made this video with iSymDVR for iPhone)
Here's a video of a common problem I get during my daily winter driving with my 2007 Honda Fit. It's rather hard to stop, even at low speeds (sub 20 km/h or 12mp/h). I understand the physics of it but I don't get why the ABS is so finicky.
I end up yanking on the handbrake and that makes my car come to a sudden stop (the kind that makes your upper body lean forward from the force of inertia). So if my handbrake can make my car stop suddenly, why is my ABS telling my car to keep travelling at 10 mph because of loss of traction? If stopping traction is possible, why does ABS not take advantage of at least some stopping traction?
Knowing most posters on this forum I am expecting a sea of flaming especially from people that live in southern Arizona who are convinced winter tyres are a waste of money. Go ahead do your worst
#2
12-17-2013, 02:19 PM
The function of ABS is to allow you to steer the car, not stop it, interestingly enough. Good luck steering on ice or icepacked snow though... too bad there's not a way to lower the ABS sensitivity for these situations, it's good to be able to lock the tires sometimes so they dig in.
Boy, I don't miss that at all (Chicago native, learned to drive there)
Boy, I don't miss that at all (Chicago native, learned to drive there
)
#3
12-17-2013, 02:32 PM
ABS is not designed to allow you to steer the car, it is designed to aid stopping the car, thus its name. The ABS will measure the ability to stop, which is a function of your brake system and tires. If your tires are losing traction, it will modulate the brakes. If your front tires have less grip then the rear, this would explain why you feel that you have better braking using the handbrake, which activates the rear brakes.
The ABS is not telling the car to travel at any speed. You are driving too fast for conditions, especially as shown when approaching the first stop sign.
The ABS is not telling the car to travel at any speed. You are driving too fast for conditions, especially as shown when approaching the first stop sign.
#4
12-17-2013, 02:36 PM
And why does the ABS modulate the brakes?
So the tires don't lock up and you can steer the car/ avoid an accident.
Edit: Fun fact: I can stop a car faster without ABS than with ABS being a spoil sport.
So the tires don't lock up and you can steer the car/ avoid an accident.
Edit: Fun fact: I can stop a car faster without ABS than with ABS being a spoil sport.
Last edited by Wanderer.; 12-17-2013 at 02:38 PM.
#5
12-17-2013, 05:13 PM
To shorten the braking distance. The ABS does not know which direction you want to be heading, only that the car isn't slowing down with equal capacity.
#6
12-17-2013, 06:14 PM
You're both right.
Locked wheels (skidding) prevents the car from turning regardless which way the wheels are pointed. Antilock Brake Systems allow steering to function by avoiding locked wheels.
This can also shorten stopping distances. Skidding has less friction than not skidding at least on dry surfaces (probably wet too). When the wheels lock and you skid, you're melting the tires creating a thin layer of liquid rubber that lubricates where they contact the road.
I'd like to see comparisons of stopping distance on snow/ice. Pumping the brakes to avoid locking the wheels is SOP without ABS.
The jury is out on whether ABS prevents any loss (property/lives). When people panic stop and lock the brakes they're probably better off traveling in a straight line than turning and hitting something they didn't see. Also faster stopping increases being rear-ended by someone.
On being able to stop faster with the emergency (hand) brake, I forget, but a lot of cars have 3 channel ABS. Each front wheel is sensed and pulsed separately, but the rear wheels are pulsed together if either locks which could cause reduced friction if one or the other of the rear wheels has better traction. 4 channel ABS avoids this.
Locked wheels (skidding) prevents the car from turning regardless which way the wheels are pointed. Antilock Brake Systems allow steering to function by avoiding locked wheels.
This can also shorten stopping distances. Skidding has less friction than not skidding at least on dry surfaces (probably wet too). When the wheels lock and you skid, you're melting the tires creating a thin layer of liquid rubber that lubricates where they contact the road.
I'd like to see comparisons of stopping distance on snow/ice. Pumping the brakes to avoid locking the wheels is SOP without ABS.
The jury is out on whether ABS prevents any loss (property/lives). When people panic stop and lock the brakes they're probably better off traveling in a straight line than turning and hitting something they didn't see. Also faster stopping increases being rear-ended by someone.
On being able to stop faster with the emergency (hand) brake, I forget, but a lot of cars have 3 channel ABS. Each front wheel is sensed and pulsed separately, but the rear wheels are pulsed together if either locks which could cause reduced friction if one or the other of the rear wheels has better traction. 4 channel ABS avoids this.
Last edited by Steve244; 12-17-2013 at 06:26 PM.
#8
12-17-2013, 06:52 PM
Fatal crashes where people successfully steer themselves off the road have increased with ABS...
Here's a bit that explains how ABS actually increases stopping distances on gravel or snow (ice, not so much). (source)
Here's a bit that explains how ABS actually increases stopping distances on gravel or snow (ice, not so much). (source)
The effect on stopping distance in straight-line panic stops is not uniformly beneficial for four-wheel ABS ...
Four-wheel ABS reduced stopping distances by only 5 percent on dry concrete, but had a substantially larger effect on wet asphalt or concrete (14 percent on the average).
Finally, four-wheel ABS lengthens stopping distances on gravel by 28 percent: A car with the wheels locked causes gravel to build up in front of the wheels, resulting in a plowing effect that slows the vehicle quicker than ABS (although steering control is lost and the car may yaw). Surfaces with other loose material, such as snow, would have a similar effect.
Four-wheel ABS reduced stopping distances by only 5 percent on dry concrete, but had a substantially larger effect on wet asphalt or concrete (14 percent on the average).
Finally, four-wheel ABS lengthens stopping distances on gravel by 28 percent: A car with the wheels locked causes gravel to build up in front of the wheels, resulting in a plowing effect that slows the vehicle quicker than ABS (although steering control is lost and the car may yaw). Surfaces with other loose material, such as snow, would have a similar effect.
#10
12-17-2013, 07:12 PM
#11
12-17-2013, 09:01 PM
I'm driving at 30 KM/H "cruising" speed (18 MPH) and the brakes were applied long before it got dangerous. You can see my speed does go down from 30 to 20 KM/h (18 to 12 mph) but then stays a steady 20 until near impact. Do you expect me to drive at 12 MPH around town? Come on! We got like 5 month of this s#@t here in Quebec. I still think this is weak ass brake performance.
#12
12-17-2013, 09:03 PM
The reason you are having so much trouble stopping is because the tires have nothing to grip to. ABS or not you can't stop if your tires are slicker than a greased pig. All season tires become hard in cold conditions and can't grip to snow. Snow tires remain pliable and grippy when cold. They also have siping to give more surface area to grab the snow.
Snow tires, bro.
Snow tires.
You can't be stopping so late and depending on ABS to stop you. I notice the Fit activating the ABS when braking on rough dry surfaces so it makes sense that it would be working doubly hard on slick ones.
Snow tires, bro.
Snow tires.
You can't be stopping so late and depending on ABS to stop you. I notice the Fit activating the ABS when braking on rough dry surfaces so it makes sense that it would be working doubly hard on slick ones.
Last edited by GoFits; 12-17-2013 at 09:09 PM.
#13
12-18-2013, 12:36 AM
Thanks for the suggestion. I am running brand new Michelin XIce 2 tires I ordered through tire rack! They must be on their 60th mile or so. Plus, I am running on downsized 14" rims which is supposed to help with the increased sidewall.
Plus, in Quebec, we call them winter tires since they are supposed to perform on snow and ice. I've heard ppl call them snow tires, just sounds funny to me. In Quebec, winter tires that have a mountain with a snowflake printed on them are required by law after the 15th of December, so we all gotta have 'em!
I must say I really like the Michelin Xice tires but I hate how the ABS is so finicky. I will try to brake softly and earlier. I just tend to avoid "riding" the brakes because of wear but I will try lighter more constant pressure to try and avoid the damn ABS!
More and more I've been wanting to disable the ABS for winter driving. I've heard of people installing an ABS switch to be able to manually turn on and off the ABS. Must be an easy thing to do but still, if I got in a crash, even if my switch was in the on position, I'm sure my insurance would be leaving me high and dry.
Plus, in Quebec, we call them winter tires since they are supposed to perform on snow and ice. I've heard ppl call them snow tires, just sounds funny to me. In Quebec, winter tires that have a mountain with a snowflake printed on them are required by law after the 15th of December, so we all gotta have 'em!
I must say I really like the Michelin Xice tires but I hate how the ABS is so finicky. I will try to brake softly and earlier. I just tend to avoid "riding" the brakes because of wear but I will try lighter more constant pressure to try and avoid the damn ABS!
More and more I've been wanting to disable the ABS for winter driving. I've heard of people installing an ABS switch to be able to manually turn on and off the ABS. Must be an easy thing to do but still, if I got in a crash, even if my switch was in the on position, I'm sure my insurance would be leaving me high and dry.
#14
12-18-2013, 12:49 AM
The guys on the impreza forums went all crazy over their ABS disabling switch. I'd love to get me some threshold braking! Check out this neato mod:
DIY ABS Toggle Switch - DirtyImpreza Forums
DIY ABS Toggle Switch - DirtyImpreza Forums
#15
12-22-2013, 04:27 PM
The ABS on my '09 Fit is usually fine, but I've come to the conclusion that on snow and ice, it's terrible--much worse than some other cars I've had.
I started noticing that once the ABS kicks in and starts pulsing, the rate of deceleration decreases dramatically, even scarily so. I also noticed that I could get a little more deceleration by carefully using the handbrake.
However, the handbrake only works on the rear wheels. So I did another experiment in a snow-covered parking lot. I got going about 20-25 MPH and hit the brakes. When the ABS started pulsing, I turned the key off, instantly disabling the system.
I was able to stop in a much shorter distance. The results were consistent and repeatable.
The downsides were that I lost the vacuum booster after about 2 pumps, so the pedal became heavy and difficult to modulate. Also, with the Fit's short wheelbase, it was quick to lose directional stability if one wheel did lock up, and obviously, I needed to restart the engine when I was done braking.
I can't just go turning the key off at every stop sign though. I wonder if there's a better way. Ideally, I'd like to disable the traction control (it's not really helpful, as I already know how to drive without it), and the ABS, but keep the stability control active. I doubt that's possible though. If I just pull the fuse to the actuator, I'm sure I would lose all three.
Therefore, I'd like a switch or a button that I could turn on and off at will. I'd mostly turn it off while braking IF the ABS is not being effective, but I'd leave it on most of the time.
I googled "disable ABS for winter" and got this forum as the first result. I wasn't looking for advice specifically for the Fit, just wondering if I was the only one who ever did or wanted to do this. However, since I'm member here, I might as well ask.
Any suggestions?
I started noticing that once the ABS kicks in and starts pulsing, the rate of deceleration decreases dramatically, even scarily so. I also noticed that I could get a little more deceleration by carefully using the handbrake.
However, the handbrake only works on the rear wheels. So I did another experiment in a snow-covered parking lot. I got going about 20-25 MPH and hit the brakes. When the ABS started pulsing, I turned the key off, instantly disabling the system.
I was able to stop in a much shorter distance. The results were consistent and repeatable.
The downsides were that I lost the vacuum booster after about 2 pumps, so the pedal became heavy and difficult to modulate. Also, with the Fit's short wheelbase, it was quick to lose directional stability if one wheel did lock up, and obviously, I needed to restart the engine when I was done braking.
I can't just go turning the key off at every stop sign though. I wonder if there's a better way. Ideally, I'd like to disable the traction control (it's not really helpful, as I already know how to drive without it), and the ABS, but keep the stability control active. I doubt that's possible though. If I just pull the fuse to the actuator, I'm sure I would lose all three.
Therefore, I'd like a switch or a button that I could turn on and off at will. I'd mostly turn it off while braking IF the ABS is not being effective, but I'd leave it on most of the time.
I googled "disable ABS for winter" and got this forum as the first result. I wasn't looking for advice specifically for the Fit, just wondering if I was the only one who ever did or wanted to do this. However, since I'm member here, I might as well ask.
Any suggestions?
#16
12-22-2013, 07:51 PM
OK, here is your first post from Southern Arizona, y'all. What's all that white stuff on the ground?
OK, we don't get snow in Phoenix, which is a blessing, cuz the people here don't know how to drive even in the rain. (Think I'm kidding....) However, we actually DO have some serious snow in Northern Arizona, say from Prescott & Payson on up to Flagstaff (altitude 7,000 ft), and it can be really trecherous driving up there. I-40 is the main hiway thru N. Ariz, and every year it gets shut down cuz of an 18 wheeler flipping, etc etc. Lotsa people from Phx go up to Snow Bowl in Flagstaff to ski, and you better take your chains. Ah yes, the fun of driving in the white stuff....
OK, we don't get snow in Phoenix, which is a blessing, cuz the people here don't know how to drive even in the rain. (Think I'm kidding....) However, we actually DO have some serious snow in Northern Arizona, say from Prescott & Payson on up to Flagstaff (altitude 7,000 ft), and it can be really trecherous driving up there. I-40 is the main hiway thru N. Ariz, and every year it gets shut down cuz of an 18 wheeler flipping, etc etc. Lotsa people from Phx go up to Snow Bowl in Flagstaff to ski, and you better take your chains. Ah yes, the fun of driving in the white stuff....
#17
12-23-2013, 03:10 AM
The ABS on my '09 Fit is usually fine, but I've come to the conclusion that on snow and ice, it's terrible--much worse than some other cars I've had.
I started noticing that once the ABS kicks in and starts pulsing, the rate of deceleration decreases dramatically, even scarily so. I also noticed that I could get a little more deceleration by carefully using the handbrake.
However, the handbrake only works on the rear wheels. So I did another experiment in a snow-covered parking lot. I got going about 20-25 MPH and hit the brakes. When the ABS started pulsing, I turned the key off, instantly disabling the system.
I was able to stop in a much shorter distance. The results were consistent and repeatable.
The downsides were that I lost the vacuum booster after about 2 pumps, so the pedal became heavy and difficult to modulate. Also, with the Fit's short wheelbase, it was quick to lose directional stability if one wheel did lock up, and obviously, I needed to restart the engine when I was done braking.
I can't just go turning the key off at every stop sign though. I wonder if there's a better way. Ideally, I'd like to disable the traction control (it's not really helpful, as I already know how to drive without it), and the ABS, but keep the stability control active. I doubt that's possible though. If I just pull the fuse to the actuator, I'm sure I would lose all three.
Therefore, I'd like a switch or a button that I could turn on and off at will. I'd mostly turn it off while braking IF the ABS is not being effective, but I'd leave it on most of the time.
I googled "disable ABS for winter" and got this forum as the first result. I wasn't looking for advice specifically for the Fit, just wondering if I was the only one who ever did or wanted to do this. However, since I'm member here, I might as well ask.
Any suggestions?
I started noticing that once the ABS kicks in and starts pulsing, the rate of deceleration decreases dramatically, even scarily so. I also noticed that I could get a little more deceleration by carefully using the handbrake.
However, the handbrake only works on the rear wheels. So I did another experiment in a snow-covered parking lot. I got going about 20-25 MPH and hit the brakes. When the ABS started pulsing, I turned the key off, instantly disabling the system.
I was able to stop in a much shorter distance. The results were consistent and repeatable.
The downsides were that I lost the vacuum booster after about 2 pumps, so the pedal became heavy and difficult to modulate. Also, with the Fit's short wheelbase, it was quick to lose directional stability if one wheel did lock up, and obviously, I needed to restart the engine when I was done braking.
I can't just go turning the key off at every stop sign though. I wonder if there's a better way. Ideally, I'd like to disable the traction control (it's not really helpful, as I already know how to drive without it), and the ABS, but keep the stability control active. I doubt that's possible though. If I just pull the fuse to the actuator, I'm sure I would lose all three.
Therefore, I'd like a switch or a button that I could turn on and off at will. I'd mostly turn it off while braking IF the ABS is not being effective, but I'd leave it on most of the time.
I googled "disable ABS for winter" and got this forum as the first result. I wasn't looking for advice specifically for the Fit, just wondering if I was the only one who ever did or wanted to do this. However, since I'm member here, I might as well ask.
Any suggestions?
The way I'm getting around it now is by practising threshold braking. As soon as a I feel like my ABS is kicking in I "ride" the brakes as much as possible. I just don't usually like using my brakes like that for wear reasons but what the hey, I figure pads are cheap.
Also, you say you lose directional control when braking; that's because you switch off your engine. When your wheels start slipping the engine rotates the wheels aimed in your intended direction of travel which helps retain directional control when skidding so with no power you must be just sliding forwards. A well timed handbrake and throttle combo really helps fight the understeer of driving in thick snow and slush.
#18
12-23-2013, 09:13 AM
Took me a minute to find this, but I knew someone posted about successfully disabling the ABS. This is on NON-VSA model, not sure if and how it translates to Fits with VSA. Excuse English I believe he is French Canadian.
First, ABS & automatic brake repartition system are good for most of situation. Especially when you bring kid to school or kiddengarden when your mind is not totally on the road and when something happen the reflex of average driver is to step on the brake. In that situation driving assistance are good. Or in some area receiving snow or icy rain when normally is not the case, and a majority of driver have limited experience with that type of weather.
When the ABS and repartition starting to be crap are when you want to drive much more on the edge (wet track, rallying etc) in that case all of your sense are sharpened and stick on the road and car behavior, in that case the driving assistances for a fit or civic (i mean average car, not like BMW M3) are over past or during severe winter condition like here in Quebec.
I do TSD rally with my fit 2010 and i have tried to disable the ABS for my first event without success, steering wheel lock every time i try. I made the rally with the ABS and brake repartition (what a crap) every time i try to place the car in a drift to negotiate a turn the system fighting against me. Many people think that the technic to place a car in drift is to use the hand brake … false. The most used technic is named left foot braking and the hand brake can be used during an Oh shit situation. During a 250kms event I use it 2 times only. For my second event it is mandatory to disable those system. I cal a friend in Honda R&D in Ohio and he tell me to try to unplug the rear sensor not the front one. I do it and it works and the car react very well now. I made some test and the brake distance on hard ice and also in deep snow are much more shorter at 80 kms the car stop on half distance in both condition but I little bit more unstable. I have studded tires on the FIT and the best way to take all the advantage of the stud on the ice are to disable the ABS but I don`t recommend to disable the ABS in daily driving and also for people that doesn`t have the skills in that particular way the drive the car (rally).
That is the DIY to disable ABS for Honda FIT 2010 without traction control
1-Lift horizontal portion of both rear seat
2-In the middle where the seat belt buckle attached to car body, fold up the carpet
Unofficial Honda FIT Forums - finito's Album: Rally Fit 2010 - Picture
3-Locate the little white connector passenger side
Unofficial Honda FIT Forums - finito's Album: Rally Fit 2010 - Picture
4-Unplug the white connector passenger side
Unofficial Honda FIT Forums - finito's Album: Rally Fit 2010 - Picture
When the ABS and repartition starting to be crap are when you want to drive much more on the edge (wet track, rallying etc) in that case all of your sense are sharpened and stick on the road and car behavior, in that case the driving assistances for a fit or civic (i mean average car, not like BMW M3) are over past or during severe winter condition like here in Quebec.
I do TSD rally with my fit 2010 and i have tried to disable the ABS for my first event without success, steering wheel lock every time i try. I made the rally with the ABS and brake repartition (what a crap) every time i try to place the car in a drift to negotiate a turn the system fighting against me. Many people think that the technic to place a car in drift is to use the hand brake … false. The most used technic is named left foot braking and the hand brake can be used during an Oh shit situation. During a 250kms event I use it 2 times only. For my second event it is mandatory to disable those system. I cal a friend in Honda R&D in Ohio and he tell me to try to unplug the rear sensor not the front one. I do it and it works and the car react very well now. I made some test and the brake distance on hard ice and also in deep snow are much more shorter at 80 kms the car stop on half distance in both condition but I little bit more unstable. I have studded tires on the FIT and the best way to take all the advantage of the stud on the ice are to disable the ABS but I don`t recommend to disable the ABS in daily driving and also for people that doesn`t have the skills in that particular way the drive the car (rally).
That is the DIY to disable ABS for Honda FIT 2010 without traction control
1-Lift horizontal portion of both rear seat
2-In the middle where the seat belt buckle attached to car body, fold up the carpet
Unofficial Honda FIT Forums - finito's Album: Rally Fit 2010 - Picture
3-Locate the little white connector passenger side
Unofficial Honda FIT Forums - finito's Album: Rally Fit 2010 - Picture
4-Unplug the white connector passenger side
Unofficial Honda FIT Forums - finito's Album: Rally Fit 2010 - Picture
#20
12-23-2013, 11:39 AM
The guys on the impreza forums went all crazy over their ABS disabling switch. I'd love to get me some threshold braking! Check out this neato mod:
DIY ABS Toggle Switch - DirtyImpreza Forums
DIY ABS Toggle Switch - DirtyImpreza Forums