Originally Posted by Flyingdoctor
Threewheelbonnie, it's nice to have someone You meant on 4 wheel systems (or 3 wheels!) I'm sure but there is some confusion. IMHO ABS on a bike is only of any use when braking in a straight line as soon as you lean the bike over to steer you will have to come off the brakes or you'll lowside. .
The same is true for a bike, it's just very wierd to do it. ABS works on slip, which you can oversimplify as the speed of the wheel versus the speed of the axle. So, a rolling wheel (50 kph tyre/50 kph axle) has zero slip, a locked wheel 100%. Depending on the (Hard) road surface, a wheel at 10-70% slip produces a proportional brake force and a lateral/steering force at 50-100% of the zero slip condition for that tyre surface combination. A locked wheel produces about 10% of the brake force and a very low number for the side force, hence you stop long with the back end out, or short because the front end went under!
It does work, but the natural reaction we all know is to release the controls, go round the obstruction then go back on the brakes. If you release the controls, the brakes of course come off, EBA on a bike could be lethal if you vered onto a loose surface. If you stayed on the brakes and lived with the off geometry due to compressed springs etc. you would be better off.
I've done this once. A leraner car driver pulled out, saw me and stopped dead. I braked, realised I was going into the side of the car, went for the gap round the front, onto a wet painted area and stopped with the R1100R's front axle about a foot away from the nose of the car, inline with the badge on the grill. I'd braked all the way through an S at 40-0 mph over a lane change of about 3 meters on a surface that had a Mu value (grip level) about the same as ice.
Not using your rear brake looses you about 25% of what's available. Seems to make no sense to me.
The integral system on some BMW's is power assisted. An ABS failure leaves you with uncontrolled, over powerful brakes which is bad. A power assistance failure leaves you with a basic set up that needs the strength of three people to operate. Both will ruin your day, unlike an unpowered system that 99 days out of 100 will get you a long way home with the light on so long as you don't try the emergency stop on the wet paint!
The solution off road should be a Mu selector. This is what 4x4's have. The switch doesn't turn the ABS off, it increases the allowed slip before it acts. Hence you get the debris built up to brake on, plus the control when you really need it. I guess BMW will go this route next.