ABS brakes
in [Cars]
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From: Alan Baker on 5 May 2010 04:24 In article <cpu1u5d24dcg73osel1vfuf3nrsvv028cp(a)4ax.com>, Ashton Crusher <demi(a)moore.net> wrote: > On Mon, 03 May 2010 23:50:20 -0700, Alan Baker <alangbaker(a)telus.net> > wrote: > > >In article <rs8vt5d3522s43sircri0i60a10hndfh9p(a)4ax.com>, > > Ashton Crusher <demi(a)moore.net> wrote: > > > >> On Wed, 28 Apr 2010 19:12:05 -0500, russotto(a)grace.speakeasy.net > >> (Matthew Russotto) wrote: > >> > >> >In article <slrnhthhs7.er2.aznomad.3(a)ip70-176-155-130.ph.ph.cox.net>, > >> >AZ Nomad <aznomad.3(a)PremoveOBthisOX.COM> wrote: > >> >> > >> >>I have too. You're not driving; merely a passenger when you're > >> >>sliding like that. You also run the risk of turning sideways, > >> >>backwards, or rolling the vehicle if you encounter sudden friction > >> >>while turned sideways. > >> > > >> >You're not a passenger when sliding with all four wheels locked; > >> >you've reached the limits of your control and will have to back off > >> >the brakes if you want to do anything else, but you're not out of > >> >control. > >> > >> You are on low friction wet pavement. > > > >Nope. Because you can release the brakes whenever you need to. > > > > If the need is to stop, releasing the brakes is not "control". If the need is only to stop, there is no need for any other control. > > >> > >> >You're not going to turn sideways > >> > >> If there is lateral differential friction, which occurs often enough > >> it can be an issue, you will spin anywhere from 10's of degrees to > >> 360+ degrees, all the while going "straight" ahead. > > > >Nope. I've made a lot of test runs, and it doesn't happen. > > > >Empirical data trumps theory every time. > > > I've made hundreds of test runs on different friction levels of both > wet and dry pavement including both uniform and non-uniform lateral > friction and I can assure you that from real world empirical data, not > theory, that the car with four locked tires will spin as I previously > described. If all you've done is some runs on dry pavement or wet > pavement with good uniform friction you simply have not experienced > the full range of what can happen. I have also seen many people try > to do these tests and who think they have locked all the wheels but > they have not, including experienced "expert" accident > reconstructionists. Except I know how to lock up all four wheels and I deliberately did tests in non-uniform lateral friction situations. Look up John Powell: <http://www.powellmotorsport.com/index.php?module=htmlpages&func=display& pid=24> -- Alan Baker Vancouver, British Columbia <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>
From: Alan Baker on 5 May 2010 23:28 In article <a4211743-1073-45c3-af68-1ce7c9bdd84b(a)e1g2000yqe.googlegroups.com>, Dave__67 <spamTHISbrp(a)yahoo.com> wrote: > On Apr 28, 7:18�pm, Alan Baker <alangba...(a)telus.net> wrote: > > In article > > <4f3fd957-83e5-4ad6-8f37-d0c92cdc3...(a)s9g2000yqa.googlegroups.com>, > > > > > > > > �Dave__67 <spamTHIS...(a)yahoo.com> wrote: > > > On Apr 27, 1:37�pm, Alan Baker <alangba...(a)telus.net> wrote: > > > > In article > > > > <e00930b2-999a-4467-adec-85b62b909...(a)v14g2000yqb.googlegroups.com>, > > > > > > �Dave__67 <spamTHIS...(a)yahoo.com> wrote: > > > > > On Apr 26, 2:41�pm, Alan Baker <alangba...(a)telus.net> wrote: > > > > > > In article > > > > > > <9bd36917-1c4c-48ba-bb9b-7061a9d6a...(a)z7g2000yqb.googlegroups.com>, > > > > > > > > �Dave__67 <spamTHIS...(a)yahoo.com> wrote: > > > > > > > On Apr 22, 9:04�pm, Ashton Crusher <d...(a)moore.net> wrote: > > > > > > > > On Thu, 22 Apr 2010 05:08:07 -0700 (PDT), Dave__67 > > > > > > > > > > <spamTHIS...(a)yahoo.com> wrote: > > > > > > > > >On Apr 21, 11:55�pm, "Nick Naim" <orb...(a)ix.netcom.com> wrote: > > > > > > > > >> I pegged her at 70 years old plus minus. > > > > > > > > >> She pulled �out of a fast food on my left in a heart beat > > > > > > > > >> I,m in the left lane of thru traffic. > > > > > > > > >> I,m on the binders on ABS and they are working on overtime. > > > > > > > > >> I come to a stop 3 feet from her right front fender. > > > > > > > > > > >If your ABS is kicking on on dry clean pavement you need > > > > > > > > >better > > > > > > > > >tires- > > > > > > > > >you're throwing away stopping distance! > > > > > > > > > > >Dave > > > > > > > > > > How do y9ou figure that? �ABS works, wet or dry, to maximize > > > > > > > > the > > > > > > > > amount of time the tire is at or near peak friction level. � > > > > > > > > > No, it does not. > > > > > > > > > ABS is designed to allow you to still steer while mindlessly > > > > > > > whomping > > > > > > > on the brakes. To do so it has to leave a little traction on the > > > > > > > plate. > > > > > > > > Again, not quite. ABS will reduce the amount of force applied to > > > > > > the > > > > > > brakes whenever conditions result in the tire starting to lock up. > > > > > > > > One of those conditions could be a change in the friction of the > > > > > > surface, but one could also be that you've turned the wheel. > > > > > > > > So there is no traction "left on the plate" in the way you meant. > > > > > > > > > Anyway, on dry pavement, if you can lock up the brakes, your > > > > > > > brakes > > > > > > > are better than your tires. If you improve the grip of the tires > > > > > > > you'll stop faster. > > > > > > > > Not just on dry pavement. :-) > > > > > > > > -- > > > > > > Alan Baker > > > > > > Vancouver, British Columbia > > > > > > <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg> > > > > > > > If the algorithms and sensors were perfect, and there were no control > > > > > loop delay, sure. > > > > > > Sorry, but they don't have to be perfect. Just better than human. And > > > > give the speed of human reactions, that's not that hard. > > > > > > -- > > > > Alan Baker > > > > Vancouver, British Columbia > > > > <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg> > > > > > I'm stating clearly that ABS leaves some traction 'on the plate' > > > unused. The fact that an expert using skilled braking technique on dry > > > pavement can stop faster with the ABS off proves this > > > incontrovertibly. > > > > The fact that a few experts can brake better than ABS is beside the > > point. > > > > That's the whole point- if ABS used all available traction no expert > could outbrake it. True, but almost completely irrelevant. > You agree that a true expert can outbrake ABS when it's straight+dry > so you either must agree that ABS leaves some traction on the table, > or you are one of those people that can hold two controverting ideas > at the same time yet feel no dissonance. It leaves very little on the table; certainly less than most people would leave. > > > > And they didn't outlaw ABS in F1 because it was going to make braking > > worse... > > > > It was going to make braking in the turns easier, srtraight-line dry > braking indeed would have suffered. You can prove that, of course... > > > > > > > > I'm not debating improvements ABS gives in most circumstances compared > > > to human brake modulation > > > > For most people -- including even most very good drivers -- ABS will > > give shorter, more controlled emergency braking. > > > > That's the fact. > > Why are you arguing when I'm clearly stating I agree? I'm not arguing this point. But your overall idea that ABS "leaves traction on the table" to leave some for steering is wrong. -- Alan Baker Vancouver, British Columbia <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>
From: Ashton Crusher on 8 May 2010 00:22 On Wed, 05 May 2010 01:24:51 -0700, Alan Baker <alangbaker(a)telus.net> wrote: >In article <cpu1u5d24dcg73osel1vfuf3nrsvv028cp(a)4ax.com>, > Ashton Crusher <demi(a)moore.net> wrote: > >> On Mon, 03 May 2010 23:50:20 -0700, Alan Baker <alangbaker(a)telus.net> >> wrote: >> >> >In article <rs8vt5d3522s43sircri0i60a10hndfh9p(a)4ax.com>, >> > Ashton Crusher <demi(a)moore.net> wrote: >> > >> >> On Wed, 28 Apr 2010 19:12:05 -0500, russotto(a)grace.speakeasy.net >> >> (Matthew Russotto) wrote: >> >> >> >> >In article <slrnhthhs7.er2.aznomad.3(a)ip70-176-155-130.ph.ph.cox.net>, >> >> >AZ Nomad <aznomad.3(a)PremoveOBthisOX.COM> wrote: >> >> >> >> >> >>I have too. You're not driving; merely a passenger when you're >> >> >>sliding like that. You also run the risk of turning sideways, >> >> >>backwards, or rolling the vehicle if you encounter sudden friction >> >> >>while turned sideways. >> >> > >> >> >You're not a passenger when sliding with all four wheels locked; >> >> >you've reached the limits of your control and will have to back off >> >> >the brakes if you want to do anything else, but you're not out of >> >> >control. >> >> >> >> You are on low friction wet pavement. >> > >> >Nope. Because you can release the brakes whenever you need to. >> > >> >> If the need is to stop, releasing the brakes is not "control". > >If the need is only to stop, there is no need for any other control. > >> >> >> >> >> >You're not going to turn sideways >> >> >> >> If there is lateral differential friction, which occurs often enough >> >> it can be an issue, you will spin anywhere from 10's of degrees to >> >> 360+ degrees, all the while going "straight" ahead. >> > >> >Nope. I've made a lot of test runs, and it doesn't happen. >> > >> >Empirical data trumps theory every time. >> >> >> I've made hundreds of test runs on different friction levels of both >> wet and dry pavement including both uniform and non-uniform lateral >> friction and I can assure you that from real world empirical data, not >> theory, that the car with four locked tires will spin as I previously >> described. If all you've done is some runs on dry pavement or wet >> pavement with good uniform friction you simply have not experienced >> the full range of what can happen. I have also seen many people try >> to do these tests and who think they have locked all the wheels but >> they have not, including experienced "expert" accident >> reconstructionists. > >Except I know how to lock up all four wheels and I deliberately did >tests in non-uniform lateral friction situations. > If all four wheels were locked and there was a friction differential between the left wheel path and the right wheel path the physics dictates that the car WILL rotate. If your car did not rotate either the wheels were not locked or there was no differential friction. Perhaps you are thinking I'm referring to a "spin" in the sense of a spinning top, that would be rare, it's a rotation that continues as long as the car is moving and as long as the friction differential exists. The greater the differential and the higher the starting speed (hence longer the stop) the greater the amount of rotation. Most of the time it's rarely more then 30 to 45 degrees. I have been on wet low friction surfaces sufficient to allow a full 360 degrees of rotation all the while going "straight" ahead. I've also been on uniform low friction surfaces where the car did not rotate but slid sideways "downhill" off the crown toward the side of the road. >Look up John Powell: > ><http://www.powellmotorsport.com/index.php?module=htmlpages&func=display& >pid=24> And?? I saw nothing applicable to this discussion there.
From: Alan Baker on 8 May 2010 01:17 In article <hqo9u5dr0n0f6bd2624293pn3jftt3nl3v(a)4ax.com>, Ashton Crusher <demi(a)moore.net> wrote: > On Wed, 05 May 2010 01:24:51 -0700, Alan Baker <alangbaker(a)telus.net> > wrote: > > >In article <cpu1u5d24dcg73osel1vfuf3nrsvv028cp(a)4ax.com>, > > Ashton Crusher <demi(a)moore.net> wrote: > > > >> On Mon, 03 May 2010 23:50:20 -0700, Alan Baker <alangbaker(a)telus.net> > >> wrote: > >> > >> >In article <rs8vt5d3522s43sircri0i60a10hndfh9p(a)4ax.com>, > >> > Ashton Crusher <demi(a)moore.net> wrote: > >> > > >> >> On Wed, 28 Apr 2010 19:12:05 -0500, russotto(a)grace.speakeasy.net > >> >> (Matthew Russotto) wrote: > >> >> > >> >> >In article <slrnhthhs7.er2.aznomad.3(a)ip70-176-155-130.ph.ph.cox.net>, > >> >> >AZ Nomad <aznomad.3(a)PremoveOBthisOX.COM> wrote: > >> >> >> > >> >> >>I have too. You're not driving; merely a passenger when you're > >> >> >>sliding like that. You also run the risk of turning sideways, > >> >> >>backwards, or rolling the vehicle if you encounter sudden friction > >> >> >>while turned sideways. > >> >> > > >> >> >You're not a passenger when sliding with all four wheels locked; > >> >> >you've reached the limits of your control and will have to back off > >> >> >the brakes if you want to do anything else, but you're not out of > >> >> >control. > >> >> > >> >> You are on low friction wet pavement. > >> > > >> >Nope. Because you can release the brakes whenever you need to. > >> > > >> > >> If the need is to stop, releasing the brakes is not "control". > > > >If the need is only to stop, there is no need for any other control. > > > >> > >> >> > >> >> >You're not going to turn sideways > >> >> > >> >> If there is lateral differential friction, which occurs often enough > >> >> it can be an issue, you will spin anywhere from 10's of degrees to > >> >> 360+ degrees, all the while going "straight" ahead. > >> > > >> >Nope. I've made a lot of test runs, and it doesn't happen. > >> > > >> >Empirical data trumps theory every time. > >> > >> > >> I've made hundreds of test runs on different friction levels of both > >> wet and dry pavement including both uniform and non-uniform lateral > >> friction and I can assure you that from real world empirical data, not > >> theory, that the car with four locked tires will spin as I previously > >> described. If all you've done is some runs on dry pavement or wet > >> pavement with good uniform friction you simply have not experienced > >> the full range of what can happen. I have also seen many people try > >> to do these tests and who think they have locked all the wheels but > >> they have not, including experienced "expert" accident > >> reconstructionists. > > > >Except I know how to lock up all four wheels and I deliberately did > >tests in non-uniform lateral friction situations. > > > > If all four wheels were locked and there was a friction differential > between the left wheel path and the right wheel path the physics > dictates that the car WILL rotate. If your car did not rotate either True: as far as it goes. The question is *how much*. > the wheels were not locked or there was no differential friction. > Perhaps you are thinking I'm referring to a "spin" in the sense of a > spinning top, that would be rare, it's a rotation that continues as > long as the car is moving and as long as the friction differential > exists. The greater the differential and the higher the starting > speed (hence longer the stop) the greater the amount of rotation. Most > of the time it's rarely more then 30 to 45 degrees. I have been on > wet low friction surfaces sufficient to allow a full 360 degrees of > rotation all the while going "straight" ahead. I've also been on > uniform low friction surfaces where the car did not rotate but slid > sideways "downhill" off the crown toward the side of the road. > > > >Look up John Powell: > > > ><http://www.powellmotorsport.com/index.php?module=htmlpages&func=display& > >pid=24> > > > And?? I saw nothing applicable to this discussion there. Naturally. -- Alan Baker Vancouver, British Columbia <http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg>
From: Matthew Russotto on 8 May 2010 20:07
In article <e18vt5t8qcr4cjcibu7qkmveb455gbdqfk(a)4ax.com>, Ashton Crusher <demi(a)moore.net> wrote: >On Wed, 28 Apr 2010 18:01:52 -0500, russotto(a)grace.speakeasy.net >(Matthew Russotto) wrote: > >>In article <bbeft5hfniv2tfhknmpm1oh71jpbp3m65n(a)4ax.com>, >>Ashton Crusher <demi(a)moore.net> wrote: >>> >>>I'm not too keen on the idea of "effective" being that when the >>>pavement is wet is to go sliding out of control. >> >>If you lock up all four wheels, the car does not go "sliding out of >>control". It behaves in a quite predictable manner, sliding >>straight in the direction it was going when the wheels locked up if on >>a flat surface. > > >If by predictable you mean your ONLY choice is to *hope* you don't hit >whatever winds up in front of you since you have no control over your >trajectory then sure. No, that's not your only choice. You can always release the brakes and try something else. >If by predictable you mean that you know you'll >be aimed somewhere but you don't know if it will be aimed forward, 45 >degrees, sideways, or backwards, or god knows which way, then yeah, >it's real predictable. IME, doesn't happen. The car rotates only slightly, unless you were spinning to begin with. What you're describing sounds more like driving on wet ice than merely locking the brakes. -- The problem with socialism is there's always someone with less ability and more need. |