Adventures in trail braking

Discussion in 'The Perfect Line and Other Riding Myths' started by mars, May 2, 2013.

  1. atomicalex

    atomicalex silly aluminum boxes

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    Fajita Dave - you have a valuable point. As noted, the art of riding well lies in knowing how much you can load the front before washing out (managing the available traction), and this is the balance that trailbraking is chasing. It is IN NO WAY a black-and-white technique, and this is what makes it problematic to teach and use. One must be comfortable in an analogue world, so to say. The technique is relatively simple - modulate and bias braking into the turn in a manner that allows the maximum amount of speed to be carried through the turn and remain available at exit. The physical actions are also relatively simple - roll off braking under suitable bias and roll on throttle, downshifting as necessary. It all sounds so simple!

    It comes down to judgement calls.

    The role of trailbraking on the street is not to maximize corner speed. It is instead to become competent at the brake-lean-modulate-downshift-throttle transition that can bail your ass out if you get caught in a bad situation in a corner.

    The fact that this enables you to enter corners a little hot when you want to is only a side benefit. :freaky

    Regarding geometry, it is the opposite of Rule 1. It keeps the bike in a relatively squatted geometry, rather than the extension of the suspension that throttle brings on. As rake and trail are relative to frame geometry, these don't change per se, but the effective rake (relative to the road surface) will change depending on how hard you are on the front brake versus the rear. At first, you dive a lot, but as you get more proficient, you come in more level. One thing in my experience has been that I can reduce the amount of bounce I get from getting on throttle, but I have the feeling the bounce is more due to riding a big thumper than other factors..... :wink:
    #81
  2. chippertheripper

    chippertheripper motorcycle junkie

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    I will agree that braking before the corner is safest for the street.
    Braking before the corner is not the fastest technique.
    In each situation, coming off the brakes smoothly is key, because you don't want your forks to pogo and mess up your cornering experience.
    At the end of the day, getting through each corner successfully should be goal #1, because you can't win if you don't finish.
    And how else are you going to pick up (insert desired sexual partner here) in the Starbucks parking lot if you're lying on the side of the road somewhere?
    #82
  3. HooliKen

    HooliKen Awesome is a flavor

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    I personally do not see the benefit of trail braking while street riding and it is useless offroad, at least to me.

    Your front tire has (x) amount of traction available. When you use some braking you lose some turning.

    If track days and getting around said track as fast as possible are your thing, then go ahead and have a ball.
    #83
  4. David R

    David R I been called a Nut Job..

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    With slow maneuvers, I apply the rear brake and the bike is more stable and I have more control.

    Is this trail braking too?

    David
    #84
  5. HooliKen

    HooliKen Awesome is a flavor

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    Maybe one of the "experts" can weigh because I am not sure.

    But I do the same thing with the rear brake. Use the clutch and rear brake often to stabilize at parking lot speeds and stop signs.
    #85
  6. AzItLies

    AzItLies Been here awhile

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    Not really.

    Trail Braking relates to cornering, and while it can be just the rear brake (or just front, or both), that doesn't equate to "I just used the rear brake, so I must be trail braking".

    It's a common misunderstanding. It's best to just remember it relates to cornering, and high speed cornering usually.

    Agree with others, mostly on the street, I'm not trail braking in corners. But! if I come up on a decreasing radius turn, or I misjudge my entry speed...

    yeah, I'm glad I know a little about trail braking.

    Cheers
    #86
  7. Tripped1

    Tripped1 Likely Lost.

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    There are all sort of benefits on the street, particularly if you don't know the roads you are on. I'd wager everyone has been surprised by a corner before. If you only break before the corner you are forced into a later apex (may be good or bad) and you may have to carry more corner speed, the ability to brake AND corner means that you can bleed off more speed than you would otherwise.

    So its risk the wash before apex, or risk the wash at apex.....or just not be able lose enough speed to negotiate the corner.

    Of course, but if you are on even a moderately sporty street tire, you have WAY WAY WAY more traction available than many give credit. I've had my 675 on its front tire only at about a 30* lean, hanging off the side and everything. I wasn't running slicks or even DOT race tires, they were just diablo rosso corsas, an aggressive street tire. Granted, that was on a track so that allows some extra due to better asphalt, but I came to the conclusion years ago that most sport touring tires are far far more than you need for the street, you have to be going so bloody fast to get near the limits of traction that its near suicidal.
    #87
  8. HooliKen

    HooliKen Awesome is a flavor

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    Agree with it all. But of course an argument could be made that if you need to trail brake on an unfamiliar road, then you are going to fast for conditions/skill level.

    The grip level on even DS tires is truly amazing now. I cannot believe how some of the DOT DS tires I have run on the SE grip compared to years past.

    I am not saying that I personally do not trail brake....:wink:....but not sure that it is something beginners should be focusing on until they have some seat time.
    #88
  9. sloperut

    sloperut Adventurer

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    Where can I find some better lean angle components? :wink:

    Carry on.
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  10. mars

    mars Starbucks anyone?

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    When I was a turn 1 corner worker at the recent MotoGP in Austin I couldn't believe the amount of smash in the front tires as they entered the corner. The rear wheel was hopping off the ground while they were turning. I could only imagine how hot that tire was by the time they hit the apex. I watched Lorenzo try and square off the corner during practice but eventually they all did a very intense trail braking move in to turn 1.
    #90
  11. atomicalex

    atomicalex silly aluminum boxes

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    David, no, not really. The primary purpose of trailbraking is to scrub speed, which, during slow speed maneouvers is not an issue. You are using brake modulation to settle the suspension, though, and that is a great skill to keep up. The suspension settling that occurs during trailbraking is a side effect, not the primary purpose.
    #91
  12. shaddix

    shaddix Banned

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    Two questions, understanding I have never been on a track in my life.

    Lee Parks book says braking at lean requires more cornering force from the tire than the added traction from the forward weight transfer adds. I guess that is because you are also requesting more braking force as well? I posed a question to Nick Ienatsch asking about the differences between wheelies and stoppies at lean angle and he replied that a stoppie at lean angle is absolutely possible, just not an efficient technique for cornering so you don't see racers doing it. Also he noted that usually the front tire cannot sustain as much lateral traction so while it's possible it is not to the level possible on the rear.

    Second question, regarding limits. Is there an appreciable difference in the stress on the tires at different velocities if the acceleration is the same? Dragging knee while on the binders at 80mph is any different from doing it at 140? Given the same lean angle and same deceleration rate.
    #92
  13. Capt Crash

    Capt Crash Been here awhile

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    "Professionals" call this "dragging the rear brake".
    #93
  14. HooliKen

    HooliKen Awesome is a flavor

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    :lol3
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  15. chippertheripper

    chippertheripper motorcycle junkie

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    I concur.
    I will say that exceeding the available traction several times has taught me a lot. Not that anyone WANTS to bin it, but you learn lots from doing so.
    Lucky for me, I did most of that on a motard, which are free to crash. No damage. Oh, and in leathers too.
    #95
  16. Tripped1

    Tripped1 Likely Lost.

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    There isn't close to as much traction on the front, there is a lot less area, you basically never want to pull the rear up when you have any real amount of lean, its not what you would call an idea situation, for the rear it doesn't really matter a lot of the time coming off apex on a hairpin you have next to no weight on the front wheel anyway. A lot of the time it happens in if you jump the throttle and the slides a little bit, it will almost always pick up the front when it catches.



    I can't claim that I have ever had a knee down while still on the brakes at 140, I've slide the front from trailbraking at that speed, but that was kind of an emergency, I was chasing a buddy that was using a race line vice a "trackday" or qualifying line, as he put it "You may be faster in the turn one, but you aren't beating me too it." Basically I was busy staying on his rear and missed that he didn't start to brake until he was two markers deeper than I have ever attempted that corner, so getting it hauled down from 160 or so (the rev lights are on in 6th gear there) taught me a couple lessons, 1) that I can actually pull that off 2) that I NEVER want to do that again, I was nearly sideways to apex, with the front sliding and I got everything back in line with about 5mm left on the outside of the curbing.

    Great if you are in AMA, NOT FUCKING FUN on a street bike.

    I don't race for a reason, I'm not willing to ride with that level of commitment, at 80 if I'm on the brakes at all with knee level lean going something is fucked up, usually by the time you start feeling with your knee you are completely off of the brakes
    #96
  17. pizzaman383

    pizzaman383 Adventurer

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    I frequently see (or at least say) things differently than others so I'll give it a go on trail braking.

    The key thing about trail braking is that it makes the entry into the corner less of a black and white corner entry point into a range that lets you adjust the exact point where you stop braking and start turning. I find that making these adjustments give me the flexibility I need to adapt do changing conditions on the street. On a track, you are always going into the same corners again and again. This lets you pick your braking and turning points with very fine specifics. On the street, I'd argue that it's even more important for riding aggressively on the street to allow the flexibility that trail braking gives.

    There's another point that's not generally discussed. The amount of aggression or how close to the edge of the traction envelope seriously impacts whether trail braking is possible. If you are riding at the back of a group of several riders you may not be running at the edge of your envelope and you can trail brake. If your bike is capable of reaching much higher corner entry speed than it can carry through the turn then you will frequently be needing to scrub off a very large amount of speed before the turn. This is best done by braking when vertical. To me this means that sometimes you need to heavily break when vertical.

    Putting these two together gives me the ideal solution. Do your heavy, hard braking with the bike vertical then finish by trail braking into the corner as it makes sense. Maybe this is exactly what's meant but the point doesn't seem to be made in a way that I got it.

    I learned these same lessons many years back with my 1978 toyota corolla and my 1986 corvette. I decreased my autocross times (and scared my passengers) the most when I kept on the throttle as long as I could, did maximum braking right before the turn, and then rode through the turn at the very edge of traction.

    When I took the MSF BRC ten years ago to get back into motorcycle riding I heard the don't brake in turn lessons and it didn't quite make sense. I was braking in the turn in every lesson. My Tiger lets me make line adjustments, brake, add or reduce throttle, change my weight, etc. without any negative consequences. This has led me to using that flexibility whenever it makes sense.

    There is one other part of the discussion that I can corroborate. My Tiger has very soft suspension. It's better now that I worked on the suspension but it's still soft compared to most bikes. The control I have and the speed I can carry through corners is hugely impacted by how loaded the suspension is. If I brake maximally with front and rear brakes right before a corner exit point and enter the turn with the suspension fully weighted to the front then I have to deal with the transfer of the suspension back to normal while I'm in the first half of the turn. I found that it's waaay more stable if I brake maximally with both brakes before the turn then back off the front brake near the beginning of the turn and trail off the rear brake until closer to the apex of the turn. For my Tiger, trail braking makes it hugely more stable through the turns and I'd be crazy not to use it both on the street.
    #97
  18. Frostback

    Frostback Frostback

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    The unorthodox front suspension on the R12 GS means less geometry change with braking so the benefits of trail braking are probably less, but I still do it. My goal is to be very smooth in throttle-brake transitions. I find it hard to modulate the throttle on a snatchy and lash-prone shaft drive while using the same right hand to feather the front brake. I am trying to practice the series of transitions that goes something like:

    1. Off throttle & hard onto the front brake (rear is not much of a player here)
    2. Lean in and decrease brake in proportion to lean all the way up to the apex.
    3. Just past the apex, all braking is done and throttle roll-on begins
    4. The more upright the bike, the more throttle can be applied.

    #3 is where I have the roughest transition. Need work there.

    The R1200 os not going to lift the front so I can whack it pretty hard as I
    approach full upright.

    Lee
    #98
  19. Fajita Dave

    Fajita Dave Been here awhile

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    That one is a tough call on the street. If you were on a track chances are your tire temps were getting near 200*F depending on your pace. At that temp sport tires are pretty much a round ball of glue that adheres to the track. I'm sure you can lift the rear tire while leaned over at street tire temps but it wouldn't be 30*.
    #99
  20. atomicalex

    atomicalex silly aluminum boxes

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    I think you are right on with most of the (crazy) trailbrakers around here so far.... It's a valuable tool in the kit, so keep it clean and ready for use.

    I think most instructors are a little bit freaked out by people with motorsports experience. Our threshold of risk is just different.