Decreasing radius downhill turn....

[choneofakind]

Others have mentioned the issue of turning in early. I never thought about that when I posted.

Your line could have also been a factor in your discomfort with that turn. Stay wide as long as you can.

Don't worry about being too "aggressive" with your body positioning on the road. I'm not saying drag knees here, but getting your entire upper body inside and down will help a lot with reducing the lean angle and keeping the bike stable. Keeping the bike stable through turns is more important than worrying about looking too aggressive.

[robmilchling]

Have you perhaps watched twist of the wrist 2? The book is a good read but I feel some of the concepts are a bit hard to visualize without having spent a good deal of time on the track already, the video, although simplified and some of the acting is a bit rough, is much easier to digest. To me, the biggest point it covers is in regards to weight transfer on a bike through the corner. On my favorite road there is a few nasty downhill corners that I loaded the front entirely too much on at first and luckily was still well within the traction limits, but after reading and watching Twist 2, I've become much more comfortable with them.

[Motofool]

Extreme hanging-off does nothing to increase the capability of the tires to grip; it only allows a little better functioning of the suspension for road irregularities.

If you are already dragging metal parts, OK, stretch a bad-for-street situation by moving the rider CG farther in, gaining three to five more degrees of total lean (provided you have good enough rubber).

A subtle steer input in those conditions is more than enough to overwhelm a marginal front tire's grip.

It is unwise to put yourself into that extreme situation anywhere but in a controlled environment (read track).

Pitch stability is what demands attention from the rider.
Throttle (acceleration) and brake (from brakes and engine) (deceleration) has dramatic effect on overloading either tire's contact patch.

Nothing to invent here: Keep 0.1~0.2 G acceleration during any turn.

In the case of a descending curve, gravity is helping in achieving the ideal acceleration and weight distribution (maybe too much for a step hill).

How and how well you do it is the key skill.

"Rule Number One:
Once the throttle is cracked on, it is rolled on evenly, smoothly, and constantly throughout the remainder of the turn.
At the point where the correct transfer of weight is achieved by the rider (10 to 20 percent rearward) by using the throttle, any big changes in that weight distribution reduce available traction.
Once the bike is fully leaned into a turn, changes in tire load, either evenly (both wheels, most easily done in a crested road situation) or alternately (front to back, back to front, from throttle on/throttle off) must then either underweight or overweight the ideal load for that particular tire/bike combination." - Keith Code

[geeker]

Originally Posted by Motofool

Nothing to invent here: Keep 0.1~0.2 G acceleration during any turn.

How does one quantify acceleration g-forces without a means to meter it?

[choneofakind]

Originally Posted by Motofool

It is unwise to put yourself into that extreme situation anywhere but in a controlled environment (read track).

Agreed. And it's lots of fun when in that controlled environment.

The skill of good body positioning is still good to have on the street because we all happen upon turns that are a little tighter than we thought they were, or find an animal or new pothole or whatever that we weren't expecting, and good body positioning keeps the bike stable and ready for inputs to safely steer around surprises. Was that a run-on sentance? hmmm...

But definitely, keep the knee dragging on the track. That level of riding is just asking for an accident on a road.

I tend to be pretty conservative on the street, but I still work on my (upper) body positioning whenever I ride. At the track, I realized just how tense my upper body was, so now I've really been working on relaxing my elbows and hands, and getting myself to look further through the turns without tensing my neck and shoulders. I have been doing all this with my butt planted firmly in the center of the seat and I really have been making solid improvement! I have noticed that I'm smoother than before, and the bike is less nervous through turns. I also have been forcing myself to stay in 3rd gear and use engine braking instead of brakes, forcing myself to set up for the next turn with my line through the current turn. (obviously I use the brakes if I'm going too fast, but you get what I mean) It is definitely possible to work on body positioning on the street at a reduced pace without being dumb and putting yourself at excessive risk levels.

@Jiggles, that might be a good exercise for you on the 250. Take a curvy road in 3rd gear. Start out slow. Use the brakes as little as possible, and don't gun it on straights. Try and work on lines through each turn, like the one that you had trouble on, and be as smooth as possible. You want to focus on not dropping the front from chopping the throttle, and not going completely WOT so that you don't push wide at exit; become the master of taking the lines that you want to take through each turn. Relax and find a mental zen so the corners flow smoothly instead of feeling like you have to push to go faster. Just work on being smooth and keeping the bike stable and you'll find that speed comes on it's own, even though you aren't pushing at all. Does that make sense?

[Motofool]

Originally Posted by geeker

How does one quantify acceleration g-forces without a means to meter it?

"A twist of the wrist" explains it well:

"Considering that most machines in a static or constant speed situation have a 50/50 weight distribution (+ or - 5.0 percent) front-to-rear, we begin to calculate the guidelines of correct acceleration through a turn.
By the numbers, we want to transfer 10 to 20 percent of the weight rearwards, using the throttle. Technically, this is 0.1 to 0.2 G of acceleration.
Simply put, it's the force generated by a smooth fifth-gear roll-on in the 4000 to 6000 rpm range on pretty much anything over 600cc.
That's not much acceleration, but it does the job."

The idea is to load each tire properly and keep it like that.

The circles in the schematic represent the traction capability of each tire.

The rider decides the combination of longitudinal (acceleration or braking) and lateral forces (centripetal force introduced by the curve: radius and speed) that each tire will feel.
Physics will punish him immediately after the resultant force trespasses the circle for each tire.

Going downhill is a tricky situation because it naturally loads the front tire more, which is the opposite to the recommended condition.

If you accelerate to overcome that and, at the same time, to achieve the proper weight distribution, then you may start moving way too fast too soon.

Less radius requires more lean angle.
More speed requires much more lean angle.
For this type of "fun" curve, the rider needs to have extra reserve of lean angle at the beginning, which means extra slow entry speed.

I deal everyday with one of these fun curves while getting off the expressway.
It covers 270 degrees of turning from a bridge to ground level.
Very frequently I have a car tailgating me while I try to reduce the entry speed so I don't run out of lean angle at the end.

[csmith12]

Originally Posted by Jiggles

Too aggressive for me on the street, but maybe at the track

Not saying you were speeding out of control or anything but if this is how you see things, then your speeds on the street should reflect it.

Ya know.....

[Jiggles]

I often go slower than I think I can because of surprises I've found at the end of corners. Last week I was going to fast on the 1k (playing with the acceleration). And I was coming around a high speed corner that a minivan was also trying to pull out into. When I go to fast the universe sends me little reminders, hey slow down dipshit

[R1Chronicles]

Originally Posted by Jiggles

Part of it is I don't want to regularly rev over 6k until I do the 600 mi service on the bike (coming up soon)

Don't worry about over rev'ing, and you should hit the high rev's on break in. Just don't maintain high rev's for a long period of time.

[Jiggles]

I've already taken it to redline but I don't want to do that alot before getting the oil changed again

[Jiggles]

Alright I'm gna go try out accelerating through turns and the body positioning chose n friends have been talking about. I'll also take some vid so you guys can make fun of me, question is do you want a helmet cam or gas tank cam?

I'm not going back to that same road, **** that road.

There's a technical twisty near where I live that got a couple months ago, maybe I'll hit that up

[choneofakind]

idk about the camera angle you want hahaa

be careful. Work on being smooth. Have fun! I'm jelly you're able to ride right now. Dumb hw... physics, statics, circuits, and diff eq grumblr grumble grumble

[Jiggles]

I'm jelly that you have priorities

[csmith12]

On the tail, facing forward.

Your track day is coming up soon right? Getting that camera set up like that will be helpful then.

[rojoracing53]

Hey @Jiggles and you others who aren't ashamed to ride underpowered bikes. This race is coming up September-29-2012 and I know of more then a few riders that had never ridden anything like this before starting the race teamed up with people they'd never met before. The guy that is talking about the gas tank being pulled off by his leathers had never even ridden a motorcycle of any kind before the 1 hour practice we got Saturday morning. He's now battling for the lead of many races and is totally hooked on the sport of motorcycle racing.
There are also several current and Ex-Pro racers that attend as well as a few Ninjette and ninja 250r racers. Ive been meaning to post this but not sure where.

Here's a few clips from the race and let me know where you think the best forum sub page would be best to post an official invite to other Ninjette members. I'll also post more info and methods of connecting with a team so you can get in on the fun. Just think of how much you can learn from real racers in 24hr at a closed course.

Link to original page on YouTube.

Link to original page on YouTube.

[Jiggles]

Ok so I tried out what you were saying csmith and I gotta say it was a lot of fun.

And rojo, that looks awesome but I can't run

[choneofakind]

So you had good luck with working on the upper body positioning a little? Make sure to keep your hands and elbows relaxed (read: almost floppy. It'll feel weird)

Did you work on being smooth and fluid while you were transitioning?

[Jiggles]

Originally Posted by choneofakind

Did you work on being smooth and fluid while you were transitioning?

What do you mean? Basically what I did was made sure I entered turns a little slower than I normally do, stayed steady on the throttle and leaned off the bike. I noticed when my head and shoulders were sticking off my leg wanted to come out too so I just let it to where it felt natural

Now here's the other thing, I don't think I can really improve much more on the streets. Whenever I'm in a turn I start thinking, there could be a car stopped or even a slow car or some other road hazard and it freaks me out and I slow down. I'll go fast in a group ride because there's people in front of me and I'll get some warning if there is a hazard like that. But alone, I just don't like taking the risk

[rojoracing53]

Originally Posted by Jiggles

Ok so I tried out what you were saying csmith and I gotta say it was a lot of fun.

And rojo, that looks awesome but I can't run

Only one person per team has to run

[Jiggles]

Ah good. How long does each person end up being on the bike?

[rojoracing53]

Originally Posted by Jiggles

Ah good. How long does each person end up being on the bike?

It depends on your personal endurance(better fix those tubes and start pedaling) and strategy but an average on 1 hour stints so 4-5 hours of track time for a 6 person team.

[Jiggles]

So you trade off every hour?

[rojoracing53]

Originally Posted by Jiggles

So you trade off every hour?

normally

[choneofakind]

Originally Posted by Jiggles

What do you mean? Basically what I did was made sure I entered turns a little slower than I normally do, stayed steady on the throttle and leaned off the bike. I noticed when my head and shoulders were sticking off my leg wanted to come out too so I just let it to where it felt natural

Now here's the other thing, I don't think I can really improve much more on the streets. Whenever I'm in a turn I start thinking, there could be a car stopped or even a slow car or some other road hazard and it freaks me out and I slow down. I'll go fast in a group ride because there's people in front of me and I'll get some warning if there is a hazard like that. But alone, I just don't like taking the risk

I totally get that. I'm the same way, maybe just less extreme because I haven't had an accident like you.

I mean like not chopping the throttle to keep the front end from getting dropped, then using knee to knee if you slide your butt off instead of transferring movement to the bars when you use your hands to slide. And then getting your head looking further through the turn than you think is ever necessary, and relaxing your hands and arms so they're almost floppy and all your outside hand is holding onto the bars by is like your thumb and 2 fingers; the rest is just floppy there so you don't get stiff on the bars. And making smooth lines without mid-turn changes, and not turning in right away when you start looking through your turn until you're out wider and can see more. That kind of stuff you can practice at a safe speed.

[Jiggles]

I see. I very often find myself too hard on the handlebars and have to loosen up

[choneofakind]

same dude. The track really made it obvious for me.

[JA-Moo]

I can't stress enough, the best investment you will ever make for learning how to ride fast and safe, is Twist of the wrist 2.

[Jiggles]

It's sitting in an open tab just waiting to be watched

Link to original page on YouTube.

[choneofakind]

for some reason, part 1 is listed as private, but here's the other parts that I have bookmarked:

Link to original page on YouTube.

Link to original page on YouTube.

Link to original page on YouTube.

Link to original page on YouTube.

Link to original page on YouTube.

Link to original page on YouTube.

[JA-Moo]

Download it if you can, as they usually don't last long on youtube......

[choneofakind]

Actually, parts 2-7 that I linked have been up since like last februrary.

Plus it's always up somewhere on youtube...

[Whiskey]

Quick bump for this,

One of these almost caught me out today, ended up coming in too hot as it was a 12% downhill, giving it a bit more lean than I'd have liked (to the point that something solid & metallic dragged, slightly upsetting the bike) & sending me to collect a bit of long grass from the verge before tucking it back in & riding on.

Originally Posted by Motofool

Downhill taxes the front rubber a little more; hence, front braking should be avoided.

High rpm's are better; low rpm's is like coasting down with clutch-in.

Downhill introduces a natural acceleration (which you normally achieve by cracking the throttle).

If that natural acceleration is more than 0.2 G, smooth rear brake should be used.

Now the reduced radius means that your entry speed needs to be modulated for the last portion's radius rather than the first portion's radius.

If the hook curve catches you by surprise, straight the bike up in the middle of the curve and brake hard to shave speed, then resume turning.

This worked out, I ended up just about making the corner with a handful of grass in the kickstand mechanism but kept it shiny side up.

All that was left to do was turn around & show it that it'll take more than that to intimidate me.

[KawiKid860]

What about trail braking in a situation like this? If you're going too wide because the radius is decreasing, couldn't you trail brake a bit to tighten up your turn?

[Panda]

Originally Posted by KawiKid860

What about trail braking in a situation like this? If you're going too wide because the radius is decreasing, couldn't you trail brake a bit to tighten up your turn?

Yes you can.

[Motofool]

Originally Posted by Whiskey

Quick bump for this,

One of these almost caught me out today, ended up coming in too hot as it was a 12% downhill, giving it a bit more lean than I'd have liked (to the point that something solid & metallic dragged, slightly upsetting the bike) & sending me to collect a bit of long grass from the verge before tucking it back in & riding on.

This worked out, I ended up just about making the corner with a handful of grass in the kickstand mechanism but kept it shiny side up.

All that was left to do was turn around & show it that it'll take more than that to intimidate me.

Excellent nerves and save, Whiskey !!!

[csmith12]

Originally Posted by Whiskey

Quick bump for this,

One of these almost caught me out today, ended up coming in too hot as it was a 12% downhill, giving it a bit more lean than I'd have liked (to the point that something solid & metallic dragged, slightly upsetting the bike) & sending me to collect a bit of long grass from the verge before tucking it back in & riding on.



This worked out, I ended up just about making the corner with a handful of grass in the kickstand mechanism but kept it shiny side up.

All that was left to do was turn around & show it that it'll take more than that to intimidate me.

Yes, yes... good save. And this is also one of the skills documented in the TOTWII movie. Stand it up, roll off, repoint the bike, continue, but care full with this on the street. I am going to assume this was a left hand turn. What if it had been a right hander? Would you have been in the oncoming lane? What if the edge of the road was a cliff as we have seen in some videos.

Be careful out there ladies and gents.

[BRad704]

So much good info in this thread!

@RiderX1138, Jonathan... scroll back up and check out those Twist of the Wrist 2 vids. I think we talked about those the other day.

and I wish we had something, ANYthing like the M1GP closer to Memphis. I'm pretty much right between Barber and Gateway, but the trip means hotel bills and all those expenses too...

[cuong-nutz]

http://www.sportrider.com/tips/146_0...adius_corners/

[Whiskey]

Originally Posted by csmith12

Yes, yes... good save. And this is also one of the skills documented in the TOTWII movie. Stand it up, roll off, repoint the bike, continue, but care full with this on the street. I am going to assume this was a left hand turn. What if it had been a right hander? Would you have been in the oncoming lane? What if the edge of the road was a cliff as we have seen in some videos.

Be careful out there ladies and gents.

Jinked left, then into a sharp right hander then opening left (We ride on the left here) Take an eyeball for yourself

A few miles earlier on the same road there were some fairly hard turns with a cliff just over the armco for example or the wall further on


Edited to show the right corner

[Motofool]

Originally Posted by Whiskey

Jinked left, then into a sharp right hander then opening left (We ride on the left here) Take an eyeball for yourself

The speed limit there is 50 km/h (31 mph); how fast were you rolling to scrap metal?

It is a very narrow road to accomplish the stand up-brake hard-lean over again.