Author Topic: Vulfy's video thread  (Read 27829 times)

Vulfy

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Vulfy's video thread
« on: May 20, 2012, 09:38:17 AM »
I figured I'll start this thread to keep updating with my progress.  All criticism, questions and tips are VERY welcome!
« Last Edit: May 20, 2012, 02:19:45 PM by Vulfy »

Vulfy

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Re: Vulfy
« Reply #1 on: May 20, 2012, 09:51:13 AM »
Since Alabama guys are running a GP8 today, I figured I shouldn't be dragging my feet and this morning went out to do my own mini GP8.   ;D

I set up the course, based on the diagram.  Based on the dimensions, it seems to fit exactly lengthwise in two parking spaces, while trying to keep the turns within the width of same two parking spaces.
I also measured additional 10 feet between the start line and the first cone.   
I also noticed from the video that they penalize if you don't stop exactly in the Finish box after you've run your course.  I  didn't do that, so at this point I'm ignoring all the penalties associated with that. 

I also don't have any timing equipment just yet, and  for now riding solo.  So the times were derived from video clip's duration, after I watched and edited it on my computer.  These times are very rough, but for my purposes they work fine.

At first it was extremely hard to keep track of how many laps I've gone through, especially with all the concentration devoted to actually riding the damn thing!   ???

Finally I figured it was easier for me to just count the cones.   As I passed first one out of the gate, that was my first one, then I would count all the cones, and the tenth was my last and furthest cone from finish, after which I gunned it to the finish line. 

I'm pretty consistent with times, which is a good thing.  The bad thing, i'm nowhere near the times I was hoping I would get.   It seems top Gymkhana riders are getting 27-29 second runs. 
Obviously I wasn't aiming at this number, at my current level, but my hope was for around a 35 second mark. 
Unfortunately I'm hovering in the 39-40 seconds.   So 5 seconds too much of my goal. 

Here is the video.  It consists of six clean runs I did.


buzz

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Re: Vulfy's video thread
« Reply #2 on: May 20, 2012, 04:47:09 PM »
Looking good! The fastest time I posted today was a 37.9

jrobinson

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Re: Vulfy's video thread
« Reply #3 on: May 20, 2012, 04:47:44 PM »
Looks good. Thanks for the video.

Vulfy

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Re: Vulfy's video thread
« Reply #4 on: May 20, 2012, 05:54:23 PM »
Have you guys recorded any videos of your event?  Would love to take a look at how it went.

jrobinson

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Re: Vulfy's video thread
« Reply #5 on: May 20, 2012, 06:04:34 PM »
This is a video form the full course that was setup. Camera is on the front fender of a 05 HD Ultra Classic.


Motogymkhanaman

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Re: Vulfy's video thread
« Reply #6 on: May 21, 2012, 05:26:27 AM »
Good GP8 times, only 14 seconds to go!

Most riders soon reach a plateau when nothing they seem to do makes any improvement in the times, but there are a couple of tips that will really help. 1) Head snaps. As you approach the pylon and about a bike length before it, snap your head round so that your nose is pointing directly towards the other pylon. This will help you to stabilise the bike and tighten the turn. 2) Treat the pylon as the exit point of the turn and not the centre of it. Whatever distance you are away from the pylon at the exit should be added to the amount of offset you take for the next pylon and so on. Much better to be wide on the way in so that you can be close on the way out.

Also be aware that the fastest times come from the shortest distance travelled and not the highest speed achieved.   

Vulfy

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Re: Vulfy's video thread
« Reply #7 on: May 21, 2012, 10:03:32 PM »
Hahahahaha   :D  ONLY  14

1.
Got it on the head snaps, will be more conscious about it!

2.
Yes!  Thank you!  That definitely is a part of it.  My mind still treats  the cone as an obstacle to go AROUND, meaning that it needs to be in the middle of the turning arc.  While I should be treating it as an APEX of the turn, and almost hitting it as I'm already preaparing to exit the turn.   

However!
Riddle me this!

This is the clip that we've all seen multiple times by now. 



got to time   1:33

watch how this rider treats the turns.
Here is the thing that I can not understand. 

It seems that when at the cone, his rear wheel is traveling a very short arc, while his front wheel is traveling a much wider arc.
The end result is that it looks like he is turning his whole bike around his REAR wheel !

Here is the diagram of that video clip. 



Note how little his rear wheel travels around the cone, compared to the front wheel.

This one thing is driving me crazy.

When I'm riding, I notice that no matter the lean angle, no matter the brakes or speed,  my rear wheel and front wheel travel about the same arc around the cone. 
Here he manages to slow down his rear wheel, so that front is traveling around it. 


Also note, that his entrance point into the turn is pretty close to the cone,  no wide entrance here. 
« Last Edit: May 21, 2012, 10:06:04 PM by Vulfy »

buzz

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Re: Vulfy's video thread
« Reply #8 on: May 27, 2012, 08:40:15 PM »
Man I have been racking my brain trying to figure out where the extra 10 seconds is. I was out practicing today, and I have hit a plateau in the high 30 second range. It is not lean angle or commitment to the turn. I can scrape my very high dual sport pegs with out issue. I am missing some technique. 

In that video I notice that all the riders seem to be using a the width of the lane as a target for their turn. I realize that I do better when there is a visual reference. Even if it is in my peripheral vision. 

How wide are lanes in Japan? (red mark) Looks to be 8-9'.

Vulfy

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Re: Vulfy's video thread
« Reply #9 on: May 27, 2012, 11:35:34 PM »
I've noticed for myself,  during last practice, that front brake can be and should be used quite a bit in the turns. 
I come from mentality that front brake in a turn is a sure wipe-out on a bike.  I started out with just barely scraping front brake in a turn, and relying solely on the rear. 
The technique as it was explained to me is, is to come in wide,  both brakes into the turn, hard.  At the apex, release front brake and hard on the rear, swing the bike around, and gas it out. 

I noticed that I wasn't using enough front brake.  However, after a bit of practice,  it started to click in.  Progressive pressure into the turn, matching the speed to slow down to a crawl at the cone, and then let go of front brake, click bars into full lock, hard rear and start applying throttle as you swing it around. 

I'm still nowhere near the way these guys swing their bike around their rear wheel, but I think I improved my own time though. Have to time it next session. 

The thing is though,  I'm getting this weird sensation of rear wheel drifting a little bit at the turn.  I'm pretty sure it is not, just a feeling. 
Looking at Japanese riders,  I'm thinking that I should be experiencing the opposite, as they swing their bikes around rear wheel, rather than drifting rear around front. 
But again, I'm pretty sure I'm not drifting anything, just some kind of new sensation that my body is not used to, and interprets it.

Here is a diagram of how I interpret my braking into the turn.  This is just a representation of my FEELING of the brakes, so do not take those circles as exact percentages, but rather a relation of front to rear braking.  Also note the point at which i click into full lock and let go of the front, and apply even more rear.   

If anybody sees any error in my ways, please chime in.

« Last Edit: May 27, 2012, 11:57:55 PM by Vulfy »

Vulfy

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Re: Vulfy's video thread
« Reply #10 on: May 27, 2012, 11:57:05 PM »
Here is a quick video of my latest practice.  I can't really call it a "practice" as it was pretty spontaneous, and I didn't set up any cones.   This was done just to get a better feel for front brake and its limits.  This is where my diagram is coming from.   




Next time I will apply this diagram  to a proper sized figure 8 and see if it improves my times. 

I'm also noticing a hiccup in my throttle, as I come out of the turn.  I should be accelerating harder out of it, but it seems I'm costing out of it, and only when my bike is fully straight, I start gasing it.

P.S.  I was also testing out my GoPro as a side cam, since it has a wider field of view.  I don't like it, as it distorts image too much.  Will revert back to my regular pocket cam for off-tripod filming.

Vulfy

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Re: Vulfy's video thread
« Reply #11 on: May 28, 2012, 12:06:13 AM »
Oh, and just one more thing.  That practice ended with this    ;D



So please be ATGATT about this sport.  Drops happen and its a normal learning process, just be safe with yourself and those around you.

No injuries apart from a small bruise on arm and shoulder, and no major damage to the bike apart from a slightly bent bolt on a frame slider and a snapped off tip of a gear peg. 

In video it looks like I just fell to the side, but in reality my rear wheel washed out under me on a tiny patch of sand and the fact that its bald as a bald eagle  :) and its time to get a new set of tires.   

But here is another small gem that was posted today by our gymkhana brethren across the ocean.



 ;D

Motogymkhanaman

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Re: Vulfy's video thread
« Reply #12 on: May 28, 2012, 05:24:10 AM »
There comes a time in every Moto Gymkhana riders career that they realise that there is much, much more to this motorcycling lark than meets the eye. It is a little known fact that a solo motorcycle is the most complex machine to have ever been designed to be operated by just one person. A bike beats a helicopter hands down for the complexity of its modes of control and a full understanding of these interactions is at the very heart of fast attack times.

The GP8 challenge embodies pretty well all of these complexities and that is why it is so very difficult to master. In no particular order, a rider must fully understand capsize and recovery modes, steady-state bank angles, rake, trail, camber steering, steering angle, roll rates, roll steering geometry, dynamic and static stability, tyre slip angles, the combined centre of gravity, driving force ratios, spiral tracks, gyroscopic effects, squat and dive plus lots of other interesting phenomena in an almost endless list.

This is why I love Moto Gymkhana so much as it really challenges you to ride the bike and not simply use a bike to ride the road.

There are almost too many questions to answer in this thread, without being face-to-face, but there are a couple of important things to know that might help.

Vulfy is correct in saying that the front brake will do amazing things, but for beginners, we strongly recommend that it is not used as it is all too easy to fold the front with the usual expensive results. Much better to nail the overall technique using just the rear brake and then bring in the front brake to start nicking tenths from your time. A sub 30 second GP8 is perfectly possible on any bike using just the rear brake, so it is wise to get there before using the front. 

Steering by the rear wheel is an important technique to understand and we have found that the best way to illustrate what's going on is to simply roll a coin along a table top. As the coin slows, it will begin to turn one way or another as it starts to capsize. The track it describes on the table top will be in the form of an ever tightening spiral until there is insufficient energy left to support the coin when it finally falls over. Your rear wheel does exactly what the coin does in that it turns tighter and tighter as it gets slower and slower with an ever increasing lean angle. The rear wheel of your bike has an optimum combination of speed and lean angle that allows it to describe the smallest possible radius and it is this combination that you will need to find. The front wheel is used only to support the weight of the bike and to bring the rear wheel to its optimum lean angle as quickly as possible and this is what we mean by steering by the rear wheel.

The superb illustration of the track that Vulfy has posted clearly shows that a GP8 course is somewhat lop-sided in that the pylon always marks the exit of the turn and not the centre of it. It also shows a near-perfect spiral track getting tighter and tighter as it approaches the pylon and then a radius as the bike is at its optimum steady state bank angle as it rotates around the pylon until the turn is completed and the track straightens .

How wide you are as you approach the pylon is known as the 'offset' and it is a good trick to get a buddy to spot for you how wide you are at the exit, which you then add to the amount of offset until you are as close to the pylon at the point of exit that it is possible to get. Your practice method should then allow you to reduce the amount of offset whilst keeping the same distance away from the pylon at the exit.

In the time lapse stills from the GP8 you can see where this rider is losing time. At frame six, he is very close to the pylon, but the bike is only half way round the turn. He really needs to be in the same position that he is in at frame 6 only at frame 10 where you can see that his bike is now some distance from the pylon. You will also notice that he has come off full lock in frame 11 yet the front wheel is not pointing in the correct direction for the amount of offset he needs for the next pylon. Because of this he will need to travel a bit further round the course which is why he is losing time. The video of Noboru Yoshino
shows how little offset he uses and how quickly he gets the rear wheel to its optimum bank angle and how close he is to the pylon at the exit. Notice too how slowly he rotates around the pylon and how he waits until the front wheel is pointing in the correct direction before opening the throttle.

There is loads more stuff to know about setting good GP8 times, but most of the fun is in the learning and experimenting and of course endless practice.
 


Vulfy

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Re: Vulfy's video thread
« Reply #13 on: May 28, 2012, 09:29:25 AM »
Excellent reply, thank you!  The coin example is great!  It helps me visualize it much better, thank you for that as well.  Time to practice !!!
 ;D

Elessar

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Re: Vulfy's video thread
« Reply #14 on: May 28, 2012, 10:56:41 AM »
Ohh, this is so good.  I love the coin example and the idea of the offset occurred to me yesterday during my practice.  Vulfy, you and I think so much alike it's scary.  I have been using the rear brake exclusively and found it to be enough for now.  I was experimenting with lines and found the offset with the better line to the exit to work well.  I didn't know what it was called but I immediately  noticed that putting the cone in the center of the turn didn't work.  Now, I have to go back and watch the recommended videos.  Thanks for the excellent advice.

After watching the videos, as shown in V's diagram, I noticed that the riders are starting their turn more than a full bike length before the cone.  I have been focusing on the radius of the offset starting my turn almost next to the cone.  I'll have to work these points into my next practice session.  This thread is the best stuff I've read so far.
« Last Edit: May 28, 2012, 11:11:27 AM by Elessar »