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Best Emergency Braking: Roll off, rear, front, clutch.

Discussion in 'New Riders and Riding Tips' started by robsalvv, May 25, 2008.

  1. In searching for some info on emergency braking recently, I bumped into this report: http://www.fmq.qc.ca/pdf/amorce-freinage_eng.pdf which explored emergency braking techniques in a reasonably scientific manner. It does smack a little of bikers trying to be scientific... I reckon there were a couple of variables they could have tightened up on, but even so, a couple of things leapt out at me:

    The main point - stopping distance:
    In their testing, clutch-in ebrake had a mean stopping distance 3m shorter than the downshifters and 1.5m shorter than the clutch-out ebrakers. That says volumes!

    (I used to be a emergency braking clutch-in downshifter. A recent HART training course rejigged my thinking to be a clutch-out no-downshifter on the basis that you'd stop shorter - which my own testing showed was true... BUT I didn't practice clutch-in no-downshifting, which the above table shows will stop you shorter again.)

    They settled on the ideal technique being as follows:
    In short: Roll off, rear, front, clutch!

    The roll off and rear brake transfers weight forward, allowing the setup and squeeze front braking to do most of the braking in the most efficient manner. Pulling in the clutch just gets rid of a distraction. (I think I'd still want to kick down a gear or two in the last moments though)

    They made a very very good point about the benefit of practice:
    That reinforces that if you practice often, the subconscious will do what it has to do precisely. So the message is PRACTICE!

    The msgroup site recommends threshold braking as the method which provides maximum braking - but you need to be careful when practicing! http://www.msgroup.org/Tip.aspx?Num=230

    The msgroup site also has a stopping distance calculator. Worth having a play. http://www.msgroup.org/forums/mtt/images/StoppingDistance.xls

    Sooo, what's your reaction??? Do the report results fly contrary to your experiences and what you were taught???? Are they bogus results??


    The closest thread on NR discussing emergency braking technique in the last couple of years was : Hard/Emergency Braking question - worth a look.

    Bravus also had this interesting thread: Braking Distance - Bike vs Car which is worth a look too - since bike / car braking distances often come up in a bike braking thread.
  2. For me I think it depends what result you're chasing. Is there a bus blocking the entire road, or are you wanting to wash off as much speed as possible before making an evasive maneuver/negotiating a turn?

    In the latter scenario (disregarding the whole "what if you need to accelerate out of trouble bla bla"), clutch in or even too high a gear makes me exceptionally uncomfortable negotiating a change in direction if I'm near the limit. I would want to be in the right gear.

    Then of course you've got using your engine as a brake (shut up Keith Code converts). I modulate the rear much better on the clutch than I do on the rear brake pedal. Certainly not something for everyone, but that's what I do.
  3. This was how I was taught to E brake at Q Ride recently.

    If its a case of wanting to pull up in a hurry downchaging is fine. In an absolute emergency we were told to forget the gears and focus on pulling up / avoiding the incident.

    Sage advice judging by the results posted.
  4. I'm so used to blipping all the time that if I try to clutch in, shift down whilst ebraking, I'm not getting on the front brakes hard enough. So it makes sense to me to just ignore the gears, brake and clutch in - because the distraction of shifting is so apparent.
  5. That old thread was a lot of help back then! A lot of good information.

    I find clutch-in is the best method but I also agree with shifting down one or two gears right at the end so you can take off again quickly.

    I also strongly agree with your comments made about the importance of practicing this vital skill. Get out there, pick a safe, empty spot and a marker and practice stopping as fast as you can from 60km/h. You will improve, you will develop a better understanding and feel of how your bike behaves and you will get used to the feeling(s) yourself (especially when it comes to locking the brakes).

    This is an interesting point. I should really practice threshold braking as the article says, with just the front brake. I can stop in 12m from 60km/h, and although I leave a faint tyre mark I'm pretty sure it's from the rear and I know I'm not doing a stoppie so that means there is room to improve (the point where the front is leaving a mark/threshold braking or doing stoppie).
  6. Rob, you seemed to have neglected the whole 'should I put the left or right glove on first' scenario and the effect that that has on the whole emergency braking equation....

    I wonder actually if the clutch in result is just a result of the rider just focussing on the one thing and not having to consider stalling, gear changing etc...?
  7. I agree ^^.

    Wouldn't have thought that applying the rear brake first in an emergency stop was the best thing to do though. I'll personally stick to roll off, front, clutch, rear. Thankfully I haven't had the need to perform it in a real world scenario yet.
  8. The problem for me is that emergencies are, well, emergencies, and I never have the presence of mind to even progressively apply the front brake. I can't think of any way to train myself to be better at it, either - kinda hard to contrive emergency situations to practise with.

    I hate even practising hard braking, because I fcuking dropped it last time I tried that :roll:, and I have no confidence/desire to do it again.
  9. Momo, that's EXACTLY the reason to practice. Get past these hoodoo's that will fcuk you up when you really need it. That's self evident mate. Tell me that it's self evident! Plus, once you start getting it right, your 'body' learns it and is more likely to take over in a real situation.

    Cejay, I reckon this is one of those situations that putting on left or right first makes SFA difference :eek: (can there be such a thing?) ... and it's also far from being one of those bike situations that have been done to death with the same outcome each time (which is usually when the left or right glove question comes up :LOL: ...which 250cc ? Squids? Premium fuel? :) ). MTO's don't seem to have have fallen into a consensus about what's the best emergency braking technique.

    You might be right, that the downshifting is nothing more than a distraction that takes away from braking... but even so, that doesn't make the results any less meaningful. I also wonder whether the up and down motion of the gear foot is enough to unload the wheels slightly with each movement... enough to gain a couple of extra metres during braking??? :-k

    Phizog????!?!? What are you talking about dude? Why would you be blipping while downshifting in an emergency brake?? You're NOT re-engaging the engine during the process - maybe only at the end when you want to ride off, but by then your speed should be well low enough that blipping isn't needed. ...or have I misunderstood something?

    TheSav, have a proper read of the report and see what they say about roll off/rear brake first. Mind you, they're talking like 0.2secs advantage for the rear brake. Even though it's a fraction of a second, what they said makes sense to me.
  10. I'm not disagreeing with the facts robsalvv. I would like to try it out myself though and see what the real difference is. 1.5 to 3 metres could make a huge difference in an emergency situation. Could be a tad difficult to readjust after years of applying front then rear brakes.
    I do like the training wheels too!
  11. For emergency brake I do what the op said roll off, clutch in, rear, front. I made it my habit since I finished my L's course. From my understanding if I apply the rear just before the front it would reduce the chance of me locking the front(but I could be wrong). The downside of cluth in first is that its easier to lock the rear(tried both) but again if I stall(lock the rear) I cant get away quickly if I need to.

    Emergency braking probably saved me(and everyone else) more than a dozen times over the last year.

    In an emgency situation, I could use any extra braking ability(shorter stopping distance). Once I almost ran into a back of a semi. I was in the right doing 60 he was in the left lane when the left lane slowed to about 10kph he decided to dodge to my lane. At the time I was passing the car behind him. I had to beake hard from 60 to about 15kph within a cars length. I escaped with about a feet to spare....
  12. Looking through that PDF, the average time to reach a complete stop is 1.8s.

    The way to determine if your engine will push you, or be assisting in braking you, is to warm your bike up, rev it to the same revs that you'd be travelling at 100kph at in top gear, and then shut the throttle and time how long it takes for the engine to return to idle.

    If it's more than 1.8s, then the engine will be pushing you along as you brake and you should clutch-in. If it's less than 1.8s, then the engine will be helping you brake and you should leave the clutch out.

    Both of the bikes tested had pretty big engines with lots of inertial mass. On super-sports and smaller there may be real differences, especially if you also factor in the control of the bike when swerving with engine braking (easier) than swerving with the clutch in (harder).

    The whole e-braking thing is also a very specialised case. On bikes there's very few scenarios where you do not have an escape route option 'cos bikes are so small. In my personal experience of actually needing to e-brake, it's been a case of braking hard with the front with the rear wheel inches above the road, looking for an escape path, and then turning towards it and releasing the front brake to allow the rear to come back down and keep the bike under control.

    Not saying that you shouldn't practise e-braking, but to me the problem started before the e-braking was needed. I'd be asking the question: Why on earth were you travelling at 100kph with less than 40m of visibility? It becomes a question of road-craft. There are extremely few arificially constructed scenarios where a good rider with good roadcraft should ever find themselves in the need to e-brake.

    Of the two times I've needed to e-brake, both times I can track the problem back to my actions prior to obstacle presenting itself. Both times I didn't blame the other person even though they were being dangerous and should not have been where they were. Really, it was my fault for not being cautious enough.

    What I'm getting at is looking at the table, there's only a 7% difference in the braking distances for the various methods over a pretty long distance. Road surface and other factors will have a much larger effect in an emergency scenario. Seems to me that riding to the conditions will have a much larger effect on your chances of survival in an emergency situation than worrying about front/rear/clutch combinations ever will.

    Feel free to flame me. It's just how I see it.
  13. I knowww but my fairings :( I really need to develop a feel for the amount of traction I have.
  14. Left or right always has a bearing :p

    Emergency braking is such a touchy area. You can practice as much as you like and consider that you've got it down pat, but my experience tells me that in an emergency, sometimes you just don't end up as you planned. That's why ABS is so good for cars, it allows you to just bury that foot and steer. In the one time I've really needed to use it, it saved me from a certain accident (pity the poor bugger who didn't have it behind me).

    Practice does make a huge difference and certainly helps with learning to release the brakes when you have a lock up, but I was surprised just how hard you do brake when you absolutely have to. A recent near encounter with a car in Melbourne resulted in all my front suspension travel being used up (cable tie as a marker) where last years 'Mentor' day where I was demonstrating braking (all day) didn't use all the travel up.
  15. Genius. That's a good point.

    That's quite true. Very rarely have i ever needed to ebrake. Usually i can see far ahead whether someone's gonna turn across my path and when they do i've already slowed down and prepared for it in advance.

    Another valid point.

    On the road i rarely find ebraking necessary but rather braking too much. I'm terrified of the driver behind not being able to brake in time.

    Those time where i have had to brake hard its just mostly front and rear, leaving the clutch alone. I'm not fast enough to think clutch and gearing but rather braking and balancing. Had the rear start swinging sideways a few times and had to balance.

    Just wondering if going straight and braking really hard on the front likely to:
    a) flip you over the front handlebars like endo style
    b) have the front wash out resulting in ending up on your back
    c) predictably skid in a straight line

    I'm to scared to try it.
  16. +1 Cejay on all points :) The extra adrenalin of a real situation usually gets more braking going than practices - so long as it's not a panic grab. And, I stand corrected on the glove issue. :oops: :LOL: Right is might!

    Good points Flux. And I fundamentally agree.

    The roadcraft point is well made. Good robust roadcraft should and would in most cases avoid ebraking situations, and would probably more likely result in heavy braking to wash off speed followed by avoidance manouevres.

    Still I strongly advocate practicing, to overlearn the physical actions, finesse the set up and squeeze and to get used to the forces. That way, more of your dollars a left to look for the escape route rather than on the unusual attitude your bike has just taken in an ebrake scenario. This could make all the difference. (Note: performance riding will give you much of the same situational awareness and clarity, and though it's fun... I'm not advocating that route in an ebraking thread! :grin:)

    For example, I practice my ebraking often. The first one though, is usually scratchy. It's never a PB and can get a little untidy with a slight rear step out... and that's with regular practice. Contrast that to a rider that avoids practicing, or a noob who is still spending "dollars" on simply riding?? The figures achieved in the table are going to be seriously seriously optimistic.

    Momo, get your arse on your bike and out to a car park, preferably with a mentor!! Practice progressively heavier braking till you get used to the forces, then ramp them up to real ebraking runs. Do them at <25km/h and when comfy, take it up the speed scale a little bit at a time. For the sake of overlearning and bedding down the braking procedure, you don't need to go above 25km/h.

    If you want to start getting used to the real forces involved though, you don't really need to go above 50km/h. (Just be aware, if you ebrake from highway speed at some point, you'll get those forces for around 3 - 4 seconds.)

    Livingstonest - the instantaneous endo is likely if you panic grab. A set up and squeeze avoids that... mind you, move your weight forward and you can get a deliberate stopping going right at the end :twisted: :grin:

    If you do get a front skidding under a set up and squeeze, you'll need to get the front rolling again or else expect a wash out. All you need do is release the brake a little. Practice gets you used to these situations.
  17. Speaking of front end washouts when E-Breaking The one time I dropped a bike (My old SR250) was on a downhill in the wet. I had bled a little speed because there was a car sitting like it was going to come out of its drive. It did, right across in front of me. So breaks loaded all going well feel a little skipping but was looking for an escape route. When I saw the escape route is when it washed out.
    The Irony of Target fixation. If I had have fixated on the car I may not have washed out. The combination of being at the limit and starting to fixate on the escape route is probably what actually brought me down.
    Now I am not advocating fixating on a car across your path, but it is an interesting irony. (That was close to 3 years riding experience (And close to 15 actual years) ago, and maybe with what I know now I would have done better.)
    [EDIT] I actually made it through the escape route… unfortunately the bike didn’t come with me [/EDIT]
  18. F/L, if you're not careful, Joel's going to start a teach F/L break/brake movement! :LOL:

    That's a bloody good experience to share. It highlights that any time you use brakes, you take up traction. If you're hard on the brakes, you'll be taking up a lot of traction... there may not be any/much left over for turning and any steering input might demand more traction than is available.

    That's not to say that you can't brake and steer... the key point is at the most simplistic level, is if you're hard on the brakes, don't steer until you're off the brakes.

    Just on traction, the whole set up and squeeze (SUAS) thing is about traction management. A panic grab will overwhelm the available traction and you'll get onto a skid. The SUAS method gives the tyre time to deform during weight transfer and actually results in more traction (hence braking effort) as the tyre deforms into the indentations of the surface.
  19. An interesting and thought provoking paper. My technique is: SUAS front, rear, clutch (just before stalling). It's how I was taught and I've pretty much always done it that way. I have experimented with clutch in and no rear though never got much joy out of those various combinations. I practice e-braking and locking up the back once a week or thereabout,so I know how it feels. I've never applied the rear first, although I'm aware of the school of thought (Devotard if I recall) that suggests the use of the rear to "perfectly align" the machine (my memory's hazy, sorry if it's out of context).

    It appears that the results from the rider who used clutch just before stall were discarded however it wasn't clear to me why this was.

    It was interesting to note that the "less than 4" finger brakers were commited to their initial finger choice due to being "prisoners of posture".

    Rob...how/will this change your braking techniques notwithstanding your well documented back brake aversion?
  20. You could've asked me for the link nearly a week ago :roll: :grin: