Gymkhana

[TheWall]

Originally Posted by Harvey Krumpet

Have a wee look at THIS Posted earlier in the thread. Watch where the riders start to turn, well before the cone & how they use the front brake to help start the turn, with the front brake applied the bike "falls" in quickly. Notice how tight the rear wheel turns around the cone compared to the front...

That video looks a lot like what Dzen was describing here. Notice how they start the turn well away from the cone, and are just about brushing the cone with their hips at the end of the turn? There's something I can shoot for...next spring

[Vulfy]

stand by.... some very very interesting things are happening on my side....

might explain a lot! At least I'm seeing some extremely interesting things from motorcycle's geometry.

[TheWall]

Originally Posted by Vulfy

stand by.... some very very interesting things are happening on my side of things....

might explain a lot of things! At least I'm seeing some extremely interesting things from motorcycle's geometry.

Sounds interesting...

[Vulfy]

Ok, so I'm completely geeking out here, but this is a very interesting diagram.

Now please note, that this is NOT a precise simulation of the bike's physics. I was animating this by hand, and by eye, so not a lot of precision here.
However while animating, it was really obvious when the bike was sliding, if the turning radius was too large or two small, so I was tweaking each turn until it felt about right. You can still see some sliding in there, but the general idea and concept is clear.

So at the end, its not necessarily that we are turning by rear tire. You can see how wildly the geometry changes between same lean, and different twist on the bar, as well as same twist but no lean. Resulting in WILDLY different turning radius.

So the spiral is coming out here, where its a combination of these turns, you start out leaned out but small twist on the bars, and as your speed drops you keep the lean, but you twist more, which spirals you into a tighter radius.



The last turn at Twist:45 and Lean:0 is to show that lean does affect the radius, even if you still have the bars at 45 degrees.

[Storm Shadow]

Well u gota get it on the outside edge if of the tyre. Try pushing a bike in a car park. As for slide tge frame flexs abd u have frontcandvrear wheel moving at different speeds

send on a small touch screen by a guy with fat fingers

[Harvey Krumpet]

Vulfy, I bet your using an Apple.


Watching the vids of Japanese aliens, different turns on the course are approached in different ways. Open corners are taken at maximum lean / speed but with the minimum of lock whereas tight u-turns are taken at maximum lock, maximum lean only at the apex. I think... the speed on the tightest parts of the course is gained from the speed of the transition. Maximum brakes, lock & lean in, to form the turn, & hard on the gas at the limit of lock & lean to exit. The faster the transition, the faster the time.

The GP8 vid I re-posted earlier is a bit mis-leading, they seem to be riding it more like a hairpin bend on a motogp circuit, it's not maximum lock because they have plenty of space but it is maximum brakes & lean followed by hard acceleration.

I guess it's a case of gauging what is required for each part of the course, where you can carry speed & where you have to get the bike hard on the steering stops to stay on track. The faster you hit the stops and drop the bike, the tighter the turn, or rather, the faster the turn.

A wee aside, my G/F and I went for a beautiful run today, her biggest yet. 160 km. The route followed the coast & it's very technical. Uphill & downhill hairpins, tightening radius corners, dodgy surfaces etc. She was right on my tail the whole way. What she has learned riding around cones has given her the skill & reactions to safely & quickly ride her bike. She can counter steer, hold the bike on the rear brake & keep her head up to watch the vanishing point. She knows the throttle is her friend too. Learned in a car park............ Awesome ride!

[Vulfy]

Originally Posted by Harvey Krumpet

Vulfy, I bet your using an Apple.

Watching the vids of Japanese aliens, different turns on the course are approached in different ways. Open corners are taken at maximum lean / speed but with the minimum of lock whereas tight u-turns are taken at maximum lock, maximum lean only at the apex. I think... the speed on the tightest parts of the course is gained from the speed of the transition. Maximum brakes, lock & lean in, to form the turn, & hard on the gas at the limit of lock & lean to exit. The faster the transition, the faster the time.

The GP8 vid I re-posted earlier is a bit mis-leading, they seem to be riding it more like a hairpin bend on a motogp circuit, it's not maximum lock because they have plenty of space but it is maximum brakes & lean followed by hard acceleration.

I guess it's a case of gauging what is required for each part of the course, where you can carry speed & where you have to get the bike hard on the steering stops to stay on track. The faster you hit the stops and drop the bike, the tighter the turn, or rather, the faster the turn.

Very well put.
Max lock + max lean would be for the tightest turns, such in GP8.

As far as Apple, you would be wrong Hate that damn company. PC all the way!

[nuggets]

Vulfy, thanks for making that graphic. Very cool.

Harvey, post up a pic of that DT230 please. I would love to have my own 2T DS.

[nuggets]

I just got in a nice little practice session. I only did a couple of log crossings and mainly worked on my gymkhana skills.

Here is the course I was running this morning. I hope the graphic is not too confusing. Follow the arrows and numbers from the start/finish. From 1 to 10 is a full lap. It is a combo of an oval and a figure 8. It gives me an opportunity to accelerate hard out of the corners so I need to be hard on the brakes into the next corner. The combo of oval/figure 8 means that there is the same number of left and right turns.


I am seeing a big improvement in speed and smoothness. I am on the gas through a lot more of the course, and harder on the brakes. I am even starting to have the front come up when accelerating out of the corners .

I have also been working my clutch control. A few days ago, I could do a clutch wheelie maybe 1 out of 4 tries, and today, I got to the point where I am clutching up to the balance point about 5 of 6 tries.

[Harvey Krumpet]

Originally Posted by nuggets

Vulfy, thanks for making that graphic. Very cool.

Harvey, post up a pic of that DT230 please. I would love to have my own 2T DS.

The toy room...

[Vulfy]

As the storm passes over New York, all I can do is sit at home and watch some amazing riders.

[Storm Shadow]

for gymkhana i was thinking a camera should be mounted down low, to see the pegs?

[Harvey Krumpet]

Originally Posted by Storm Shadow

for gymkhana i was thinking a camera should be mounted down low, to see the pegs?

Ooh, that will give some great shots. I have mounts on the forks & radiator of the TDM, add a whole new dimension to leaning. Looking forward to the footage.

All the best Vulfy and all the other members in the path, the world is watching. That is a Biblical storm.

[Motogymkhanaman]

A really great place to mount a camera is on the handlebars, but set looking back up at the rider. You get to see those wonderful head-snaps as well as the horizon swivelling crazily in the background.

[Storm Shadow]

Originally Posted by Motogymkhanaman

A really great place to mount a camera is on the handlebars, but set looking back up at the rider. You get to see those wonderful head-snaps as well as the horizon swivelling crazily in the background.

well i still got the dvr cam on the handle bar ram mount