Gymkhana

[ohgood]

Originally Posted by Harvey Krumpet

Your point about road skills is really pertinent ohgood. On Monday in the pishing rain a car slammed the anchors on to make a right turn on a downhill, off camber, slick corner. We were in town so it was slow speed & my following distance was good. Thing is I still had to brake & steer, felt great to do it naturally & aim for my gap with no dramas rather than have an eek moment because of the conditions.

Here are a couple of short vids as promised. Slowly but surely getting their IMHO

http://youtu.be/jahGG2Hy61c


http://youtu.be/zYm2EWVxXsg

My girlfriend nearly got winged.......

Excellent ! The after effects of gymkhana are something you can FEEL in day-to-day riding. The slick road conditions are something we felt on the very hot asphalt during saturday's event, just a little muted. I hope everyone felt it, and recognized that the bike was still controllable.

Your first video shows something teached (really should be a word!) and preached but often forgotten. The head turn brings focus around, shoulders around, and the entire bike around. With just a few practices it's natural tendency to smoother turns becomes apparent. Good stuff !


Someone is going to see this, or another GK type thread today.... go out for a ride and try a couple of these things...... and grin. Ain't that shit cool ?

[Harvey Krumpet]

Originally Posted by ohgood

Excellent ! The after effects of gymkhana are something you can FEEL in day-to-day riding. The slick road conditions are something we felt on the very hot asphalt during saturday's event, just a little muted. I hope everyone felt it, and recognized that the bike was still controllable.

Your first video shows something teached (really should be a word!) and preached but often forgotten. The head turn brings focus around, shoulders around, and the entire bike around. With just a few practices it's natural tendency to smoother turns becomes apparent. Good stuff !


Someone is going to see this, or another GK type thread today.... go out for a ride and try a couple of these things...... and grin. Ain't that shit cool ?

This all started for me when my G/F started practicing the cones for her basic handling, her instructor offered me some advanced riding lessons which I jumped at & now we are out every week developing our skills. I used to think I was a reasonably good rider..... Er, no.... Probably the most enthusiastic I have been about riding since I started 35 years ago.

Watching the pros ride I noticed how early they set up a turn, almost before they reach the cone. This is what I was trying to get to grips with on Sunday. Unfortunately in the vids, my best attempts are furthest away from the camera. It makes a huge difference using the rear brake & getting the head around as the front wheel gets to the cone, less feeling of dropping the bike & on the gas very early. I will get good at this!!!!!!!!

[IndyChizzle]

Originally Posted by Vulfy

Where and when to use the clutch often leads to many interesting discussions so to help everybody get a handle on it, here is the Moto Gymkhana riders guide to the clutch.

First of all it should be noted that in comparison to brake pads clutches are very expensive to repair or replace when they wear out and overuse of the clutch can do seriously nasty things to the engine oil as it slips.

Secondly a bike is much more stable with the throttle open and the engine driving the rear wheel than it is with no drive to the rear wheel.

Thirdly the throttle and the rear brake are precision analogue controls which can be used in combination to set an exact amount of power delivery to the rear wheel.

Depending on the type of bike being ridden there are times when it is neccessary to very slightly slip the clutch, but in most circumstances the clutch is used only at the beginning and end of a course attack. Its use is often required in the big engined Supermoto machines to smooth out the power pulses and to stop them overwhelming the last bit of grip from the rear tyre and it is also used on the very big and powerful supersports machines when it is neccessary to very quickly reduce the amount of drive reaching the rear wheel.

For most bikes the clutch can simply be forgotten during a course attack as it adds another variable to manage when you have probably got your hands (and feet) full with operating just the throttle and the brake.

This was one of the best pieces of riding advice I've heard in the past year. I practiced a week ago and used the clutch until my hand hurt. The worst part was, I was constantly accelerating and decelerating and when I did the bike felt less stable (more likely to tip). Tonight, I left the clutch out and just adjusted my speed with the back brake. It takes a little getting used to, but it works much better and I could do figure 8's and circles much faster and smoother. Beware the back brake temperatures though... I wanted to see how hot I was getting my back rotor, and scorched my leather glove in an instant. I understand the brakes are made to handle that, I just was surprised how hot I could get them in 15 minutes of riding.

Does anybody adjust their idle speed in order to make this easier? My Honda makes this pretty easy, and when I adjusted from 1700 rpms to 1250 rpms I could handle the bike better. I hope to get good enough that I can handle it at 1700 rpms no problem, but in the mean time, it's a nice crutch and it allows me to not have to be on the back brakes so much.

[shaddix]

I can't wrap my head around using throttle and rear brake simultaneously. I can't reconcile this because for any particular rear wheel speed, there is an exact rpm speed to match, so I don't understand why you can't just use less throttle instead of using the rear brake at all.

[liquid_ice]

@shaddix, you are totally right if speed is the only thing you want to realize, but there is more to it.

You will build up internal forces in the bike and those will help you stabilize.

I searched for a good explanation of the physics involved, but couldn't find it, sorry.

[dredman]

Long sweeping turns may not require brakes in turns, but most tight, slow turns require brakes for a fast efficient path. A good example of why you should use brakes in a turn is the figure 8. The fastest, most efficient path is wide, fast entry, with a sharp, slow exit, as illustrated in this video

[ultrachrome]

Originally Posted by shaddix

I can't wrap my head around using throttle and rear brake simultaneously. I can't reconcile this because for any particular rear wheel speed, there is an exact rpm speed to match, so I don't understand why you can't just use less throttle instead of using the rear brake at all.

I drag my brake to prevent lurching due to chain slack. Perhaps there are other reasons but controlling this slack that is inherent to the design of the bike makes it much easier to control when riding a bike just off idle.

[IndyChizzle]

Originally Posted by liquid_ice

@shaddix, you are totally right if speed is the only thing you want to realize, but there is more to it.

You will build up internal forces in the bike and those will help you stabilize.

I searched for a good explanation of the physics involved, but couldn't find it, sorry.

We all know that wheels work like a gyroscope that helps stabilize the bike; is it possible that the engine in a Honda /Suzuki / Triumph in-line engine would also work like a gyroscope at speed? While the engine doesn't look like a gyroscope, it makes me wonder if the crankshaft spinning at a high rpms would provide the same benefit.

[Bill_Z]

My practice session today consisted of 8's. It was pretty hot, at about 93' at the Garrard County High School and I decided to ride closer to main road to see if I could entice any passing traffic to join me, or stop, just out of curiosity. No luck there, but I did have a good session.

I worked on dragging the rear brake to stabilize the turn around the cone and felt it work very well. However, I was not able to abandon the clutch within the "friction zone" so I still have that crutch to work on.

The video above shows a very experienced rider riding lock to lock on a GP8 course at speed. That rider's performance made me flinch in concern for his control, but was instructive about my riding, because I know that I am still afraid to allow the tires to do the work and that I am still trying to carry the bike around the turn. That thing gets heavy in the 93' weather. I may have exacerbated my problem by not wearing my knee pads today, because of the heat, and enhanced my fear of falling. Not good. Well, there's always next time...

[Vulfy]

My latest session. 37 seconds.


As far as dragging the rear brake, I think its a whole bunch of things rolled into one. I think the main reason for dragging the brake, IS speed control. Yes if you had reactions of a fly, and your bike responded to throttle in milliseconds, as well as there wouldn't be any slack or stretch in the throttle cable depending which way your are turning, you could manage the speed just on the throttle control.... maybe.

I think by dragging the rear brake, you are widening your margin for error. Throttle response gets smoothed out a bit. These tight turns are not constant diameter turns, they are spiral. As bike gets closer to the cone, it naturally slows down, so you have to apply more throttle to keep the speed up, and to accelerate out of the turn. Dragging the rear brake allows you to control that speed more smoothly.

[shaddix]

Originally Posted by dredman

Long sweeping turns may not require brakes in turns, but most tight, slow turns require brakes for a fast efficient path. A good example of why you should use brakes in a turn is the figure 8. The fastest, most efficient path is wide, fast entry, with a sharp, slow exit, as illustrated in this video

Originally Posted by ultrachrome

I drag my brake to prevent lurching due to chain slack. Perhaps there are other reasons but controlling this slack that is inherent to the design of the bike makes it much easier to control when riding a bike just off idle.

Originally Posted by Vulfy

My latest session. 37 seconds.


As far as dragging the rear brake, I think its a whole bunch of things rolled into one. I think the main reason for dragging the brake, IS speed control. Yes if you had reactions of a fly, and your bike responded to throttle in milliseconds, as well as there wouldn't be any slack or stretch in the throttle cable depending which way your are turning, you could manage the speed just on the throttle control.... maybe.

I think by dragging the rear brake, you are widening your margin for error. Throttle response gets smoothed out a bit. These tight turns are not constant diameter turns, they are spiral. As bike gets closer to the cone, it naturally slows down, so you have to apply more throttle to keep the speed up, and to accelerate out of the turn. Dragging the rear brake allows you to control that speed more smoothly.

Thank you, all good explanations! Makes a lot more sense now.

[Vulfy]

Here is a spliced up video of top rider, and my beginner attempts. Clearly demonstrates the difference in aggressiveness, and where I'm losing time. Pretty cool actually, helps me a great deal to see where I can improve.

[Harvey Krumpet]

I LOL'ed at the hot rear brake disc, did exactly the same thing sans gloves. It will be the first time I have ever worn out a set of rear pads. I am using the back brake consistently now, well, once i have told myself to stop covering the clutch....... The TDM will lurch on a whiff of throttle & I use the brake to keep the revs up rounding a turn so I can accelerate smoothly & not spear off the course, on the big bike the slowing effect is negligible but the engine braking compensates.

Vulfy, how wide is the area you are turning in, the 2 slabs with the cone in the middle, 6ish meters?

[Vulfy]

Harvey: each slab is about 8 feet, so 16 feet all together, a little bit less than 5 meters. Those slabs are not exact squares, so those sides are the shorter ones. so 4.5 - 5 meters wide.

40.603775,-73.885039

These are coords on Google Maps, for you to see where I'm practicing. There are a few cars parked, so you can see the size of the slabs relative to those as well..

BTW !

If anybody is in that general area, and wants to drop by do practice, you are more than welcome! Haven't had any problems with rangers or cops, but I'm trying to keep a low profile.

[Harvey Krumpet]

Tight, that's the width of road we started in, well 5 to 6 mtrs.

Here is a vid from yesterday, biggest thing I need to do for improvement on this course is think about my lines better so I can be smoother. One of the turns is on a 5 mtr wide down hill, it's quite intense to start with.