Disabling ABS

I'm just glad you guys aren't designing my car!... LOL

Professor

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Reply to
Professor
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technically, that's not quite correct, but the conditions under which abs outperforms a skilled driver are fairly narrow in scope and require the abs to "know" the difference between tires, road conditions, etc. all current abs systems "know" [afaik] is whether the wheel is locked or not, and that's "dumb".

my experience with abs is that it's actually a very good idea on garbage slush boxes like buicks. for cars like that, the suspension is so soft, that sudden application of the brakes is initially taken up in the "slush" of suspension travel, not road resistance, and the wheel can almost instantaneously lock. as there's almost no driver feedback, the driver doesn't know what's going on until the whole car is starting to break loose - not good. and in this situation, i think the compromise that is abs is on balance a good idea. with a honda otoh, it's light, tight, and the driver can instantly feel what's going on, /way/ before the car brakes loose. the suspension is /not/ sloppy, so the "instant lock" phenomenon is not a feature of daily driving. in this case, i think abs is an option, and something i personally declined when i bought a new civic back in 2000.

Reply to
jim beam

don't you think it a high risk strategy to call yourself "professor" if you don't know what you're talking about? and worse, don't know when to not /prove/ you don't know what you're talking about?

Reply to
jim beam

You are absolutely correct. I have seen this demonstrated at two performance driving schools I attented. After the instructors finished the demonstration, the students got a chance to try it. It made me a believer. I'm sure I'll get replies saying I don't know what I'm talking about and the instructors didn't either. I'll give my response ahead of time. Spend a few days and a little money and go to a school taught by professional drivers. You will be amazed at what you will learn.

Reply to
jerri

the place for abs is on slush buckets where the driver has no feedback on what's happening with the wheels, trucks where the driver has no feedback on what's happening with the wheels, locomotives where the driver has no feedback on what's happening with the wheels, planes where... get the idea?

for a light & tight vehicle like a honda [this /is/ a honda group, right?] it's only necessary if the driver can't/won't/doesn't threshold brake.

braking distance is a function of energy absorbed. abs chops up the absorption curve into chunks as it goes above and below threshold repeatedly. the abs can't moderate the degree of pressure to achieve threshold, nor can it hold it at threshold. all it can do is sense whether the wheel is locked, release, and so on. each time it releases, it passes threshold, each time it releases, it passes threshold. this may be fine in reasonable friction conditions where the braking effect between each release is considerable and the total energy absorbed quickly accumulates, but in low friction conditions, this can introduce considerable time delay into the energy absorption equation. try stopping quickly in snow with abs and see where it gets you.

Reply to
jim beam

My prediction was correct. I knew it would be. IRMC. BTW: Your "Shift Key" isn't working. PLONK! You won't stir my pot again.

Reply to
jerri

a worthy technical analysis. thanks for contributing to the knowledge pool by sharing your expertise.

Reply to
jim beam

Actually, its properly called Cadence braking

Reply to
flobert

If you'd bothered to google both terms you'd know that they are both equally accepted terms for basically the same technique.

Reply to
Sean D

not really. cadence, like abs, is where you pass /through/ the threshold of adhesion, lock and have to release. threshold is where you brake /at/ the adhesion limit, but don't pass through it.

Reply to
jim beam

So cadence braking is "pumping" the brake where you lock and unlock, whereas threshold is where you constantly apply the max pressure without locking to get the most out of the brakes, right? The technique I learned was threshold braking, where you hit the brakes hard, when you feel the wheel starting to lock, release the slightest amount of pressure to prevent locking, then gradually apply more pressure to brake as you slow down, always staying on the verge of locking. As I said earlier, a properly performed threshold brake will outperform ABS because there is no release in brake pressure. I still use threshold braking on my car. ABS just prevents locking if I accidentally apply too much pressure. It's a safeguard, but I don't depend in it.

P.S. My apologies to the poster I responsed to earlier. My response was snotty. I'd just gotten off work and was in a rotten mood.

Reply to
Sean D

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