downshift/braking methods

Discussion in 'The Perfect Line and Other Riding Myths' started by cellige, Oct 6, 2013.

  1. Florida Lime

    Florida Lime Long timer

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    As stated, and not often enough- Robbinsville, NC.
    Yes, most people downshift through each gear, one at a time, until they reach the gear desired.

    BUT, that is NOT the only way it can be done. :huh

    Tom Kipp, AMA privateer and factory rider, used to downshift through to the gear he wanted for that corner, THEN engage with the clutch to power through the corner. It worked very well for him, but I never could get the hang of doing it that way. :lol3
    #41
  2. joexr

    joexr Banned

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    On a track (road course) that you know well , that's fine , but not for an inexperienced and/or on an unfamilar corner. On dirt if you drop several gears and dump the clutch there's little penalty for skipping the tire across the ground.
    #42
  3. Florida Lime

    Florida Lime Long timer

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    Most of the posts on this page do reference the track, and since when did "engage the clutch" become "dump the clutch" ? :huh
    #43
  4. Tripped1

    Tripped1 Bitch called me a feminist.

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    You have more traction under power, the idea being to get weight onto the fat back tire (this is why sportbikes have a heavy front end bias) when coasting at speed you are loading the hell out of the front and risking a washout.

    Fun fact, you actually have more traction with a slight bit of slip happening than you do without it.

    Granted all of this primarily applies when you are nearing the limit of traction, and with today's tires that is moving pretty good. I've had my 675 on its front wheel with a 25-30 degree lean on it.
    #44
  5. joexr

    joexr Banned

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    Your not good on dirt , huh?:lol3
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  6. Florida Lime

    Florida Lime Long timer

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    As stated, and not often enough- Robbinsville, NC.
    My 'track' experiences are based on about 15 different road courses in the eastern US, so that is what I think of when I hear 'track'.
    My dirt experience is all single and double track, but not on a 'track'.
    So how does that make me 'not good on dirt" ? :ear
    #46
  7. joexr

    joexr Banned

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    It's OK that you putz around on trails.:lol3
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  8. atomicalex

    atomicalex silly aluminum boxes

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    I really cannot describe how important it is to overcome this.

    I am going through some issues with my CBR because of the linked brakes - I'm on the front medium hard and want to bring the rear in, and the front gets weird due to the check valves not being perfect. It freaks me the hell out. On the F, it's just making sure to avoid ABS. That is much easier/more manageable.
    #48
  9. Tripped1

    Tripped1 Bitch called me a feminist.

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    One call to sport bike track gear and bye bye linked brakes. I still want to know what HonDUH was thinking putting linked brakes on a CBR.
    #49
  10. beendog

    beendog Banned

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    Thanks guys, wasn't aware the front had more traction with less weight on it, I would think it's the opposite(like the rear tire is more weight=more traction). Shows how counter-intuitive some of this stuff really is.
    #50
  11. Tripped1

    Tripped1 Bitch called me a feminist.

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    Indeed, there is a lot of shit with motorcycles that goes completely against your gut.

    >...when in doubt, throttle out.
    #51
  12. atomicalex

    atomicalex silly aluminum boxes

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    I know exactly why the put them on the 250 - it's a beginner bike and some front is better than no front. But for riders with some experience and who prefer to run the bias to the front anyway, it's a crap system. Better is the BMW system that reverses it and allows the rear to be the independent brake. This only makes sense for smart riders, though. For the unwashed masses who think the front will put them over the bars, Honda is helping them to stay upright and actually stop.
    #52
  13. Horizontal

    Horizontal Goatin' Around

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    My track experience is zilch but this is the first conversation regarding front wheel braking into cornering that I've heard or read about. Fascinating stuff that certainly wasn't part of the MSF course that I graduated from.:wink:

    I suppose the technique is to just use two fingers, lightly?
    #53
  14. joexr

    joexr Banned

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    That's a personal preference , I always use one finger to brake. And you CAN brake pretty hard while leaned over.
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  15. lnewqban

    lnewqban Ninjetter

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    It is not exactly as you describe it, ............. and that misconception can be dangerous. :1drink
    Here is why:
    When the bike is turning, it leans because there are lateral forces as well as vertical forces on the contact patch of each tire (and the lean counteracts those).
    The vertical forces are the only ones that contribute to grip or traction: the more vertical force the greater the resistance of the tire to side-slide or skid (more traction).

    Available traction is able to withstand a lateral force of about 90% of the vertical force for dry asphalt, about 60% on dry concrete and about 25% on wet asphalt.

    Those vertical forces come from the weight on the tire, which can be reduced or increased on each by acceleration (more on rear than front) and braking (more on front that rear).

    That is great for accelerating and braking with the bike in a vertical position: for each case, the weight naturally transfers over the tire than needs more traction or grip.

    The problem while the bike is leaned is that the explained transfer of weight caused by inertia, also increases the lateral force on each contact patch (more for more lean angle).

    Keeping the recommended moderate acceleration during a turn, discharges the front contact patch some from both forces (vertical and horizontal) and puts that load on the rear contact patch, which is bigger and has higher capacity for that load.
    As a bonus, the suspension re-adjusts to achieve the best stability and ground clearance during the turn.

    If you will be riding on asphalt and in traffic, I highly recommend you reading this book:

    "Proficient Motorcycling: The Ultimate Guide to Riding Well" by David L. Hough

    You can find it in your local public library or buy it from here:
    http://www.amazon.com/Proficient-Motorcycling-Ultimate-Guide-Riding/dp/1889540536

    In the meanwhile, you can read good information here:
    http://www.sportrider.com/motorcycle_riding/techniques/

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    #55
  16. corndog67

    corndog67 Banned

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    You should get some professional instruction. There is some downright dangerous advise being given here, and some of it is absolutely wrong. I'm not going to go into detail about which of it is wrong, because someone will undoubtedly call me a Tea Party guy or a Liberal, and they will get extremely defensive and insulting about it. Again, professional instruction.

    Take everything you read here with a grain of salt. Because some of it is worth less than a grain of salt.
    #56
  17. joexr

    joexr Banned

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    I have to agree with you on this. Instruction IN PERSON is a safer bet than TALK from someone who Heard IT from someone else or read it somewhere , but doesn't understand it or how to apply it.
    #57
  18. MADurstewitz

    MADurstewitz MADMark

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    Ive been riding for about 45 years. A lot of dirt in the beginning (30 years) and then street. Ive learned a few interesting things about braking.

    In the dirt, downshifting rapidly while braking will get you into a berm faster than anything else. Do it right and the back wheel will hop as it locks and releases. During this you're hard on the front brake with your nuts up against the tank and your inside foot along side the front tire, ready to plant. Once you're planted, whip the bike over your leg and roll on the gas to get out.

    On the street you can engine brake as described above, but I'd limit it to emergency stops. Practice it a bit and then save it for a panic situation. Keep your body upright and hard on the front brake but not so hard as to lock it. It's very effective and can considerably reduce your stopping distance.

    In a high-speed street turn, don't downshift as described above. Downshift a gear at a time and DON'T PANIC! Give both brakes a delicate squeeze if you find yourself leaned way over and still way too fast. Delicate is the word. Just a short, gentle one or two second squeeze. It should pull you back into the sweet spot in the curve and get you out with your ass in one piece.

    In NJ, there are a number of weird exits off the interstates around here and I've gone into a few way too fast:eek1 in order to avoid getting tangled up in a knot of people driving badly. It works, but it takes a little practice. A lot of it is paying attention to how everything feels. At least for me.
    #58
  19. beendog

    beendog Banned

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    Well, I just took level 1 and 2 of Lee Parks' total control class, but they didn't discuss traction gains or loss from braking and accelerating.

    TBH, it still doesn't make sense to me as to why you would have more traction on the front with less weight, but less traction on the rear with less weight. I know for a fact when you brake, weight shifts to the front, and there is less traction at the rear. I know this because I can do a stoppie.

    I also know that weight is part of what determines your traction, so if the weight of the bike doesn't change, and you have no traction on the rear tire(because it's in the air), your front tire *must* have way more traction than it does normally. And this is why you can brake so much harder with the front than the rear. The rear slides when you get hard on the rear brake, the front doesn't, WHY? because we have way more weight on the front from braking, thus more traction. As to why that concept doesn't apply in a corner? I don't know.

    Now, I also understand that weight and brake/throttle are two separate things, which is why I posed the question of coasting through a turn. This is a concern when you would wash out the tires before scraping parts. If you are on a particularly slippery piece of wet road for example, in that case we ARE concerned with maximum TRACTION through the turn, regardless of available clearance.

    In the case of accelerating through said turn, you have weight on each tire providing traction, while you have cornering force and torque consuming traction.

    In the case of coasting through said turn, you have weight on each tire providing traction, while you have only cornering force consuming traction, no torque consuming the rear tire's traction. So we know for a fact the rear now has more traction available for cornering, but for the front, I don't know. We do have more weight on the front when coasting through, but we aren't braking, so cornering force is the only thing consuming traction.

    Now, if the rear really does have SO MUCH MORE traction available than the front because of it's increased contact patch size, perhaps the extra traction being consumed by being on the throttle(to overcome wind resistance) is less than what is being gained from having more weight on the rear. Now it seems to me that that can't possibly be the case, I would surmise that we are closer to losing traction on the rear tire when on the throttle through a corner than we are when coasting through a corner.

    The front tire equation is the one that I would be struggling with here. In neither case, coasting or on the throttle, does the front tire have anything but cornering force consuming available traction. Does having another 50-100lbs on the front tire consume more cornering force than what is provided by the added weight? Lee Parks' book says yes. But what this would mean is that the lighter your motorcycle, the higher G-force you could pull, which doesn't sound right to me. I don't think, even with the stickiest tires, that any weight motorcycle is going to be able to surpass ~1.1Gs on a skidpad.

    We have cars with no downforce available that can pull .9G on a skidpad, and they weigh a ton or more. Granted they have larger contact patches, but if a 3000lb car can pull .9G without downforce, and a 350lb motorcycle can't do much better, then how does more weight = less traction in a corner? If that was true, wouldn't the 3000lb car(with no downforce) not be able to come close to a 350lb motorcycle's cornering ability? Given that we are talking about differences of 50lbs additional on the front tire when coasting vs on the throttle, how are we going to say that more weight = less traction in a corner when apparently we can add ~2700lbs of weight(car) and not lose much if any traction?
    #59
  20. Barry

    Barry Just Beastly

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    I find that extremely hard to believe. That's a basic fundamental of brake and throttle use and the effects of both on available traction.

    Can others that have taken Lee Parks class chime in on that?

    Barry
    #60