Originally Posted by fasteddiecopeman
stopping the "stoppie" is the ABS's job.
Technically, ABS's job is to stop the front wheel from locking
, so you should still be able to do a rolling
stoppie, when the front wheel is still rotating but the braking is nevertheless strong enough for the back wheel to lift. This is possible to do with an ABS-equipped V650 but just barely
Or maybe I'm not skilled enough to do it consistently.
A stoppie where the front wheel stands still and you're being catapulted over the handlebars - I'm pretty sure it's nigh-impossible and the ABS will intervene. At least in intervened every time I tried (and I have!).
We should all keep in mind what the ABS knows and what it doesn't know. An ordinary ABS, like we have in the Versys, only sees the rotation speeds of both wheels and it must base its decisions on that information. In particular, the ABS doesn't know the bike's orientation, or whether it's entered a stoppie stance. A simplified algorithm of how the ABS might "think" is:
1. If both wheels are rotating, we're braking correctly. Don't intervene.
2. If both wheels are stopped, we're probably standing still. Don't intervene.
3. If one wheel is rotating and the other one is not, the non-rotating wheel has likely locked and I need to release some pressure from its' brake. Intervene.
(If I released the pressure to the locked wheel but hasn't started rotating, and the other one still is, I've no idea what's going on, there might be a malfunction or a sensor error. I don't understand how the front wheel hasn't resumed rotation along with the back wheel despite releasing brake pressure. This is what happens when you do a burnout and the confused ABS disables itself.)
In a non-rolling stoppie, the ABS will see the situation in point 3 and will release the front brake a bit. Unless the rear wheel happens to lock in the exact same moment as the front, which would put it in scenario 2. That's the theoretical possibility I see for ABS to not intervene correctly during a panic brake, but I've never seen it happen in practice - there are probably extra precautions taken to not confuse the two scenarios, otherwise it'd be easy to lock both wheels when using both brakes on a slippery surface. Maybe the speed reduction on both wheels must be gradual enough for the ABS to assume scenario 2?
TL;DR - no need to worry about unintended stoppies. It's hard enough to make one happen intentionally
Originally Posted by ATCKirk
I've tried some hard braking just to see what the ABS would do and as soon as I feel the chatter I released. I didn't really want to hold it long enough for the back to come up if it was so inclined.
If you feel the chatter on the brake lever (ie. ABS is intervening), there's virtually no way for the rear to lift at this point. You're not going to get enough braking force when the ABS is reducing pressure to avoid locking, even when using performance sintered brake pads.
In fact, it's a good idea to practice "riding it out" when you feel the lever chatter, as it's what you're supposed to do in a panic brake. You might have muscle memory from riding non-ABS bikes that you need to release the grip on the lever when the front locks. That's correct for those bikes, but with ABS, you're not supposed to. It's better to keep the brake squeezed (and feel it pulsing) than to try and outperform the system with your hand. If the ABS has kicked in, you evidently braked too hard in the first place, you've likely wrongly estimated the available traction - what are the chances you're going to re-estimate it better now than a bespoke system that updates itself dozens of times per second, especially considering you're now likely adrenaline-pumped and tense?
Learn to trust the technology. It's not foolproof, it won't brake for you, it won't change the laws of physics, but when it kicks in you're most likely beyond the point of applying riding technique and now in the realm of panic braking
It's gonna consistently outperform you in that particular situation because that's what it's designed for. Train accordingly, teach your muscles to recognize that lever chattering and not be afraid of it or surprised by it.
Also, you probably know this already if you've ridden in dirt, the rear brake is really
paramount for keeping the bike going where you want during deceleration. I depend on mine heavily, especially knowing that I have the safety net of the rear-wheel ABS if I overdo it. Using both brakes keeps the bike planted and stable instead of front-heavy and squirming. It's probably easier to practice emergency stops with both brakes than just the front as you don't get the "my rear is overtaking me" feeling.