ABS and Highway Spinout!

I couldn't agree more. I require my kids to put in a season of autocross (no real hardship there :-) after getting their license, in the hope that they will learn at least some of the "body" skills related to car handling. For all too many drivers, their first sensation of the car loosing grip on the road and beginning to spin is in the second or two before they hit something. At least the kids know what it feels like to spin, and what to do about it.

Well, maybe. Most drivers don't have access to facilities that train "panic" responses. These have to be reflexive to be of any use at all; in a panic situation, (by definition) there is never time to think about the proper response. Your reflexes _will_ take over, and you have to hope that they do the correct thing. In a low speed situation (at residential speeds, say up to about 35MPH), the likelihood of an abrupt steering&braking input putting the car into a spin are much reduced, probably it will just understeer. At highway speeds, the same input is probably gonna cause all four wheels to lose traction most abruptly, and with often disastrous consequences. The art is in knowing where the line is, but, again, your body has to know; you're not likely to have time to think about it. So you're toolin' along a winding mountain highway right at first light, doin' 50-60MPH. There is a rocky hillside on your right, and a steep drop-off on the other. Bambi jumps off of the hillside about

50ft in front of you. A skilled driver could probably do a dance on the pedals and miss the deer, but the consequences of a mistake are pretty grim. So Bambi walks, and you end up 100ft down in the rocks. Seen that story played out too many times. I maintain that if you are schooled such that your "panic" response is to brake, not steer in a situation like this, on the average you are gonna be better off. YMMV.

ByeBye! S.

Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101

That's OK if it's a hundred pound deer. Probably wouldn't even deploy the airbags. If it's a six hundred pound moose, not uncommon in my area, it's a whole different deal. What I'm saying here is that there are no hard and fast rules. Each situation is unique. You're requirement of a year of autocross isn't a bad idea.

For most folks who don't get that kind of experience, I would say, scrub off as much speed as possible before attempting to swerve, and get off the brake when you move the steering wheel. If the obstacle is light, (like a deer), you would likely be better off to hit it. If it is a moose, or a stone wall, or a tree, you would probably want to take evasive action.

George Adams

"All good fishermen stay young until they die, for fishing is the only dream of youth that doth not grow stale with age." ---- J.W Muller

You are expecting too much. ABS prevents wheel lock-up so that you can steer under hard braking. Cranking the wheel at 60MPH will cause a spin whether you have ABS or not.

I feel a lot of drivers don't understand ABS. It does reduce the lock-up problem, but it's not a panacea. If you "lose traction", as on ice, the wheels will lockup! It happens for in instant, but without traction the wheel has no reason to start rolling again, especially if it's not headed in the direction of travel.

Did you know BMW was the first to develope ABS for it's motorcycles many years ago? I remember reading the article and it blew me away. They had outriggers on the bike and hit the brakes HARD on soappy pavement. It went straight. But, soapy pavement has more traction than glare ice that's formed a thin layer of water between the ice and the tire.! Username munged by FixNews

I've locked the rear wheel of my cycle a few of times. You can go straight during wheel lock-up if you're going in a straight line when you lock the wheel(s) up and don't turn the vehicle before you recover traction and the vehicle suspension stabilizes.

I've also spun a VW Rabbit by stomping on the brake and turning hard when someone ran a stop sign in front of me.

Steve

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My bike riding days were in the 50's and haven't followed them much since then. I don't remember where/when I read the BMW ABS article, but I was wide eyed reading it. It talked about the research, i.e., determing the right pulsations per second, etc.

I have yet to lockup the wheels on our '03 OB. But, long ago in my racing days of the 60's (primarily slaloming with a Porsche) I learned not to just jab the brake pedal hard. Now it's impossible to stomp on the brakes even in an emergency. Which is not the way to use ABS most efficiently!!!

What kind of bike were you refering to above?

Are more mfgs using ABS on bikes now days? Username munged by FixNews

I long ago learned to be more subtle while driving, and if I need to stomp on the brake won't turn the wheel. If I need to steer, I won't brake heavily.

I ride an '82 Yamaha 400 Maxim. It's an odd bike, because they shared 90% of the parts with the 400cc Seca. So it's got a tear drop tank, but a monoshock and stressed frame engine.

AFAIK Motorcycles manufactures haven't adopted ABS like cars builders have. I don't know of any other than the BMWs. But I wouldn't be surprised to find ABS on a bike like a Honda Goldwing.

Steve

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It's right next to the toilet and just above the TV/VCR!

I've got a BMW bike with their 3rd generation ABS -- a 1995 R1100RT. I took their easlier generations for at least one or two test rides each.

Their first ABS system was pretty crude. It seemed to cycle just a few times per second and if it was the front wheel that you were braking with it felt as if it was jumping over a puddle or something each time the ABS unlocked.

When I took a 2nd generation bike out I tried it at about 60 mph on grass on an airfield. It cycled quite a bit faster but you could still feel it. But it was remarkably effective on that surface. With road tyres (not knobblies) it was ripping out 6" divots of grass (with attached topsoil) about every yard, or maybe a bit less.

With my bike you can feel an initial surge as the ABS kicks in initially, but after that any cycling is undetectable. It just stops smoothly, wet, dry, unsealed, grass. Once I got comfortable I tried stomping on the rear brake while turning a little bit, then a little bit more. Eventually I worked up to stomping hard on the rear brake while leaned over 30 degrees in a 50 mph corner. The back end immediately stepped out about a foot and then the ABS got it under control and the bike came to a smooth stop while still turning. Of course it didn't stop as fast as it would in a straight line (let alone if I'd used the front brake), but then I didn't fall off either.

A very impressive system

I once got caught in the middle of nowhere (NZ's "Desert Road") in a sudden dump of snow. I had a lot of trouble going up the hills because it was so difficult to not apply too much power. But going downhill was no problem as the ABS coped very smoothly with the icy conditions and was able to keep both front and back wheels at close to maximum traction. I don't believe there is any possible way I could have ridden that large and heavy touring bike down those icy slopes without ABS.

In start contrast, several years ago I had a US-build (GM) rental car in the snow in Seattle. It had ABS but it was *shocking*. It seemed to trigger far too easily and had a very slow cycle time and was I think worse than no ABS at all.

My Subaru's ABS is much better than that car (and I quite often drive on grassy slopes while fetching sailplanes from fields) but it's not as good as BMW's motorcycle ABS.

Not all ABS is created equal.

-- Bruce

Funny, my 2001 Forester's ABS is awful. I had the left wheeles on ice and the right ones on dry pavement and the thing took forever to stop - almost sent me through and intersection. Ironically, I saw the dry pavement on the right side and applied my brakes in what should have been plenty of distance to stop. Without ABS, I could have easily stopped much faster.

Great user report, Bruce. I'm as wide eyed after reading your message as I was when I first read the ABS development article. Sounds like magic!

I'm starting to remember that I read the article in the BMW club magazine back about 1986 or so. I'd just retired and spent all my retirement bonus on an 1884 BMW 528e. I've always bought Prosche but decided in an area with NO Porsche mechanics I'd switch to BMW where there was a dealer.

That car was something else. Black/black, 4-door, looked for all the world like a Mafia car. Cruise at 125, take freeway off ramps at 100+ and beg for more. It didn't have ABS but it made up for it in all other ways. Only a 2.8L engine, but it would hold 80mph with the cruise control on even the steepest -hills-, not mountains, in northern New Mexico...USA that is.

Ten years later I moved to Spokane, WA and got a 1988 Carrera that you could throw around at 125. WOW! Ah, memories. ;-)

Thanks, again. Hope others enjoyed your message also.

Don Username munged by FixNews

With half the cars rubber on ice and half on dry road if you applied full braking force the car would start to spin as you have practically zero traction on the left and 100% on the right. I tried this on an old runway in a car with no ABS to see what happened. as the car started to spin the rear wheel on the dry ended up on the ice and the car snapped round 180 in a flash.

If the ABS had any intelegence etc it was probably correcting your error of applying the brakes too hard and keeping the car going in a straight line by reducing the stopping ability of the left.

Alternatively the abs is not 4 channel and was pulsing one or both the wheels with the grip exactly as it is on the ice on the left, i think earlier foresters were only 3 chanel ie each front wheel on a channel of their own and both back wheels on one channel. in these curcumstances youd only have one wheel stopping you which would explain why you took too long to stop.

Ross