Gymkhana

Discussion in 'The Perfect Line and Other Riding Myths' started by Vulfy, May 6, 2012.

  1. liquid_ice

    liquid_ice Been here awhile

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    Today we had our second meeting this year, this time it was in the German city Krefeld. A bunch of Dutch people joined a few Germans and together we had a marvelous day.

    Because I'm no hero with cold weather, I was (again) with the car (i'm sorry guy's ;) )

    But just like last meeting in Amsterdam about 25 people from wich about 15 different drivers came. Some came even from 300KM up north.

    We did (as we do more often) in the morning a few exercises.
    GP8, wave, cloverleaf and a circle with 2 Jinxes.
    and in the afternoon a course.

    The circle was an excersise that was also used in the course, so people can get used to it. Also in the morning we made the excersises just a little bit more difficult to encourage a proper technique. In the afternoon the speed is just a bit higher.

    I will provide some pictures.

    I do have a question for you guys, what about air pressure in the tyres?
  2. Harvey Krumpet

    Harvey Krumpet Been here awhile

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    Probably moot for most riders but if your at the pointy end of the time sheet lower pressure will generate heat quicker & easier as the tire flexes more. Exactly the same as on a track. I know quite a few riders who drop their tire pressures down to mid / high 20's (psi) for track days & pump them back up for the ride home. Thing is, you would need to get the heat into them immediately before you start your lap. They cool quickly.
  3. Vulfy

    Vulfy Been here awhile

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    Oh no you don't!!! This thread has been on the first page for quite some time, and we got 5 star rating. We can do better than to let it slide to second page.

    Great work on the event Liquid_Ice, beautiful pictures.

    Who else is out there already, leaning and scraping footpegs?
    C'mon its been a long winter, but we need to start brushing off the cobwebs and starting to get into the groove.

    On a personal note, my both bikes have been in mechanical Limbo since December. Hopefully I will get my DRZ beastie fixed and out for this upcoming weekend, and can start putting some miles on it.

    Some beautiful riding by our Japanese friends in the new season.

    <iframe width="480" height="360" src="http://www.youtube.com/embed/MVY7Ms5EIQw?rel=0" frameborder="0" allowfullscreen></iframe>


    CB750!!!!! I had this bike a few years ago, what a wonderful machine and seems to be pretty capable in the twistiest of Gymkhana.
    Joy to watch.
  4. Motogymkhanaman

    Motogymkhanaman Been here awhile

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    Would love to be out practicing, but it's still snowing in the UK. :(

    In a couple of weeks time, it will have started to warm up a bit, so before you know it every car park in the land will be echoing to the sound of scraping footrests and whoops of delight.
  5. Motogymkhanaman

    Motogymkhanaman Been here awhile

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    Just found a nice piece of on-board video from one of our championship rounds.

    The rider is Matt Hull, Technical Editor of Ride magazine. He's a bit good at this riding lark so sit back and enjoy.

    <iframe width="560" height="315" src="http://www.youtube.com/embed/cdi-EJD6zcE" frameborder="0" allowfullscreen></iframe>
  6. CBBaron

    CBBaron Long timer

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    Still snowing here :cry

    I feel like winter is never going to end.

    Craig
  7. TheWall

    TheWall 0 miles and counting

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    Still snowing here in AK as well, which is a good thing considering I still need to replace the rear wheel bearings; change the oil, oil filter and air filter; seat the bead on the front tire that I removed last weekend (burned out my air pump before I was able to get the bead to seat, dangit!); and check the valve clearances before the spring riding season starts.

    And that's on my *working* motorcycle :baldy The XS750 still needs...well, more than I should probably list here :cry
  8. Vulfy

    Vulfy Been here awhile

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    Sorry guys for the lack of riding weather. So much for the groundhog's early spring predictions.

    Its been gorgeous weather late this week in NYC, even if a bit chilly. Picking up my DRZ tomorrow, gonna start out slow.

    Very cool video Motogymkhanaman, I love the crisp ans quick transitions, he definitely is a "bit good" at this riding stuff, haha.

    To everybody else out there. There has been quite a few views of this thread, and it can't all be by just the few people posting here.
    Don't be shy, sign up for ADV account, or if you already have one, just drop us a line here, if you find this interesting.
    Let us all know your progress, questions, concerns. New season is upon us, and we would love to share the love of this sport. :freaky
  9. fuelish

    fuelish Been here awhile

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    I find it very interesting, but don't have much to contribute. I have yet to find a spot, that has enough run off to do much of anything, that does not have lots of traffic. Practicing between a retaining wall and a building does not make for stretching your skill set.
  10. Vulfy

    Vulfy Been here awhile

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    Hmm... that might be a good point there, fuelish.

    Do we have any videos of people practicing in tight spaces?
    It is always fascinating to watch top class riders tackle a course, but the videos usually take place in a pretty large area.

    How about it ya all? What would be the smallest space that you can setup some kind of a course on?

    My first instinct would be the GP8. That can be done, within just few meters, and there are great variations of it with just a couple of more cones.


    <iframe width="640" height="360" src="http://www.youtube.com/embed/R7Ndq8AIAmw?rel=0" frameborder="0" allowfullscreen></iframe>

    Anybody else can chime in on this? As the season is warming up for me here in NYC, I'm starting to scout for new spots to practice at. After the hurricane this year, my main spot, the airfield is closed now. So back to square one.

    Saw this video recently. This one is not about the space of the course, but I'm absolutely loving the quick transitions he is making at the beginning of the course. That Left/Right Right/Left is a beautiful thing to watch.

    <iframe width="640" height="360" src="http://www.youtube.com/embed/ElORl_I25pA?rel=0" frameborder="0" allowfullscreen></iframe>
  11. Coachgeo

    Coachgeo Diesel Adventurer

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    any know of Southern OH or Northern KY moto gymkhana groups or groups forming? Contacts?
  12. Redclayrider

    Redclayrider Long time gone

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    You can go to the AMGRASS site here and ask, http://amgrass.com/ I see a lot of the same members here but it is another resource.
  13. ohgood

    ohgood Long timer

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    a driveway is big enough, dirt teaches very quickly too.

    I like school parking lots before sunset. all it takes is some chalk or rocks. leave the gravel and slide through it, its another tool. decreasing radius then flip it to increasing.... and in between do tiny circles till my head swims. swim left, turn right till it swims right....

    the most fun ? a perfect dirt bike slide on pavement. to cool off. mount cheap tires and chew on them until the edges chunk off. ya.



    I still can't fucking drift for shit though. some day.
  14. RxZ

    RxZ Legal Drug Dealer

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    I retook the basic riders course this weekend. A refresher for me, but I am selling my first bike to my little brother and wanted him to take the course first, so I took it with him.

    Anyway, after watching a lot of the videos here, and otherwise being interested in the sport... The figure-eights of the MSF course were easy! :1drink

    I tried telling the other students to watch me turn all the way around to look where I wanted to go. A couple did great, most kept looking at their front tire and the lines of the box. However, those little Eliminator 125s sure do not lean much :deal Just have to use a little more body english :evil
  15. bumbeen

    bumbeen Banned

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    Posted this in the noob thread with no response so I will give this a shot.

    Is the sole purpose of counterleaning during u-turns so that we can do them at slower speeds? If so, why can't I just sit straight in the saddle and add a few mph to my speed and maintain the same lean angle and turn radius? Or might I even hang off and do a u-turn scraping the pegs and knee at 20mph instead of 7?

    This is making me think the whole drag rear brake and counterlean business is a waste of time, just add a little throttle and you can maintain the same turning radius without having to mess with the clutch or rear brake or shifting your weight at all yes?

    Unrelated, but riding crossed up should allow you to scrub in tires more safely than hanging off or riding straight up and down yes? The main factor in the lateral traction limit of the tires is the lateral G's not the lean angle? In fact, on a dual compound tire, you're probably more likely to slip if hanging off since you might not be all the way over onto the sticky edges of the tire? Are my presumptions correct?
  16. Motogymkhanaman

    Motogymkhanaman Been here awhile

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    Hello there bumbeen welcome to the wonderful world of Moto Gymkhana.

    Lots of questions there, but essentially we are aiming to rotate the bike in the quickest possible time whilst covering the shortest possible distance.

    There are three main variations in body position, lean in, lean out and lean with (plus everywhere in between) and one of them will suit you and your bike much better than the others, so it's simply a case of finding which one it is.

    It's a bit counter-intuitive, but the slower the bike is going the quicker we can turn it. In order to ride the bike very slowly with significant bank angle we have to have what we call the balance of the bike. Riders usually rely on the forces of inertia to keep the bike balanced, but with reduced inertia from going slowly we have to be very aware of the position of the Centre of Gravity otherwise the bike could fall over. Maintaining the balance of the bike is much easier if we have the throttle open and the brake on at the same time.

    You are quite correct about lateral 'G' being the limiting factor, but this does increase significantly with bank angle so there is always a trade-off to be made and finding it is simply a matter of practice, practice and more practice. There is NO short-cut.

    A key indicator of whether or not you have got it right is when you can rotate the bike through 360 degrees in about 2.5 seconds. Get a friend to time what you can do now and then see if any changes you make to body position or amount of throttle or brake make any difference. If you find some combination that's faster do more of it, but if slower, do less.
  17. Vulfy

    Vulfy Been here awhile

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    bumbeen: coming from personal experience, riding this on the parking lot, its not that simple to just add or maintain speed and just leaning more, to turn quicker.

    If your bars are not turned, you can lean all you want, but you will still be going wide, so the trick is to get the bars turned as much as you can, and preferably to a full lock so your turning radius is as tight as possible.

    Adding speed to this, will wrestle the bars out of your hands, as the bike is trying to straighten front wheel, with more power from the rear wheel, pushing front wheel straight, as well as trying to stand up, rather than lean. With less speed, bike falls into the turn, and the front turns lighter and faster. But keep in mind that this is happening with bars at FULL lock to the side. Moto GP or street racers can lean their bikes to the point of knee dragging, but they are not twisting their bars to the full lock. At the speeds they are traveling they are covering much greater distance and wider radii than in Gymkhana, and the small adjustments to the bars are enough to put the bike into a deep dive for their purposes. In Gymkhana, we are traveling much slower and turn radius is much tighter, so we rely on the turn of the bars to get the bike turned faster, and then add lean to it, to decrease the radius even further.

    But with slower speed, as motogymkhanaman is saying, you need to counter-balance the bike, so it doesn't simply flop on its side because there is so much lean, but not enough inertia to keep it stable at that lean angle and at that speed.

    Also, adding more speed with front at full lock, can very well just start sliding the front wheel, as there might not be enough grip for that speed AT that angle of the bars.

    However, knee down, doing tight circles is possible.

    <iframe width="480" height="360" src="http://www.youtube.com/embed/K2bTLKundwA?rel=0" frameborder="0" allowfullscreen></iframe>

    This might be exactly what you are saying, however for time attack, this is not the most efficient way, and you WILL lose time on the track, as he is still doing pretty wide circles compared to what you would want to do in a Gymkhana timed event.

    In comparison to the above video, these guys turn the bike AROUND quickly.

    <iframe width="480" height="360" src="http://www.youtube.com/embed/Ikx2sJcecnQ?rel=0" frameborder="0" allowfullscreen></iframe>

    Look at how much they lean the bike AND twist the bars. But the speed of the bike is minimal (from standstill). Yes they put their foot down, but that is exactly the point. There is no way for them to counter lean to keep the bike stable at that lean angle and that speed, BUT that is probably the tightest radius possible for that bike, which is the point of Gymkhana turns.

    So to get the fastest turn-around, you are trying to get as close as possible to these guys, where the speed is enough to keep the bike counter-leaned without putting your foot down, and yet not too fast, where you can not twist the bars to a full lock for the tightest turn.
  18. Vulfy

    Vulfy Been here awhile

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    I made this graphic a while back, and hopefully it shows a little bit clearer how much turn radius is dependent on lean AND bar angle.

    <iframe width="640" height="360" src="http://www.youtube.com/embed/HUutNYsKBJo?rel=0" frameborder="0" allowfullscreen></iframe>

    As I was making this, one thing that struck me, was that when the bars are twisted fully to one side, the angle at which the bike is leaned, changes the location of the traction patch on the tire. So the more you lean your bike with full lock on the bars, the further forward the patch of the tire that is on the asphalt, moves, decreasing turn radius DRAMATICALLY.

    But with that happening, rear wheel is pushing front tire which is almost perpendicular to it, at this point, so there is a fine balance in speed, where there is enough of it to keep the bike moving, but not too much, where rear overpowers the front, and starts to slide it, as the front can not cope with momentum that rear is delivering, to turn the bike in its direction...


    I hope I'm explaining it clearly enough, and not making any major errors in my reasoning. I'm just trying to explain, what I've been feeling through the seat of my pants, on my bikes, when I do these exercises.
  19. bumbeen

    bumbeen Banned

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    Thanks! And this is why I asked here without going and trying it out myself first haha. I was thinking of doing twist 45 and lean 45 and just adding more speed so I wouldn't have to counter lean to hit my lean 45 mark. You have now created a bunch of other questions but I am indisposed at the moment to post them all! I will have to reply again when I am at a full sized computer.
  20. Vulfy

    Vulfy Been here awhile

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