flying_hun
Adverse Selection
Great stuff, Dan! Yes, I use the VP consciously, and find it quite useful.
The Vanishing Point
- Thread starter DataDan
- Start date
cowbean
Well-known member
That is a very interesting technique. I think the basic idea is something riders arrive at once they calm down, stop trying to scrape knee pucks in the twisties, etc. However, I wonder if trying to adhere to this too closely results in less smooth brake / throttle application, especially where the VP advises different behavior from The Pace.
The VP probably results in faster times through a given series of turns, as you're accelerating and decelerating to match curves within their visible limits. The Pace, on the other hand, uses throttle control instead of brakes to control entry speed, resulting in shallower deltas. Given a constant radius turn, The Pace seems like it would arrive at the minimum speed through the curve as the entry speed, whereas strict adherence to VP enters the curve at a higher speed, and advises trail braking as the VP gets closer... then a correspondingly increased application of throttle as you can see more through the turn and the VP fades into the distance.
I'm probably overthinking it -- the goal of both techniques should be the same, namely getting through a ride with maximum enjoyment and minimal risk. I think what I've come to do (without knowing about the VP), is using The Pace to set entry speed, and the VP to deal with decreasing radius turns that "delayed apexing" doesn't cover.
In any case, good read, helps to at least think about these things and visualize before getting up into the mountains.
Thanks DataDan!
The VP probably results in faster times through a given series of turns, as you're accelerating and decelerating to match curves within their visible limits. The Pace, on the other hand, uses throttle control instead of brakes to control entry speed, resulting in shallower deltas. Given a constant radius turn, The Pace seems like it would arrive at the minimum speed through the curve as the entry speed, whereas strict adherence to VP enters the curve at a higher speed, and advises trail braking as the VP gets closer... then a correspondingly increased application of throttle as you can see more through the turn and the VP fades into the distance.
I'm probably overthinking it -- the goal of both techniques should be the same, namely getting through a ride with maximum enjoyment and minimal risk. I think what I've come to do (without knowing about the VP), is using The Pace to set entry speed, and the VP to deal with decreasing radius turns that "delayed apexing" doesn't cover.
In any case, good read, helps to at least think about these things and visualize before getting up into the mountains.
Thanks DataDan!
DataDan
Mama says he's bona fide
Good question. I try to practice both--The Pace establishes attitude, and the VP helps de-mystify unfamiliar turns. I don't think they conflict and, in fact, see them as complementary. Nick writes: "The Pace decreases your reliance on the throttle and brakes, the two easiest controls to abuse, and hones your ability to judge cornering speed, which is the most thrilling aspect of performance street riding." And judging cornering speed is what the VP helps with.
The VP technique doesn't require use of brakes. Deceleration as you close in on the VP can be achieved just by rolling off the gas, depending on speed reached on the preceding straight. And that's personal preference--which, for me, is usually governed by The Pace.
The two coincide well on the point of minimum speed and turn-in. The Pace encourages slowing while upright, quick turn-in, and roll-on through the turn. Nick again: "Steer your bike forcefully but smoothly to minimize the transition time; don’t hammer it down because the chassis will bobble slightly as it settles, possibly carrying you off line. Since you haven’t charged in on the brakes, you can get the throttle on early, before the apex, which balances and settles your bike for the drive out."
It may seem that a speed profile dictated by the VP would have you trailing either the throttle or brake deep into the turn, but that's not how it works out. In fact, the transition from deceleration as you close in on the VP, to steady throttle when the VP is at constant distance, happens before you reach the constant radius segment of the turn. You see the constant radius before you get there. That's shown in the photo sequence at points 5 and 6. From those points, distance to the VP doesn't seem to change much. But from the marked-up aerial view, you can see that you're still 20-30 yards away from the constant radius segment. Thus, that visual cue from the VP can be used for steering input and roll-on, and it will happen in just about the place you'd want it to happen for riding at The Pace.
BigMatt408
RIP #58
I have already started practicing this, it is helping out a lot! :thumbup
Dr_SLO
Well-known member
The VP is an excellent guide for interpreting unfamiliar turns. The VP can also be 'increased/decreased' by minor changes in road positioning. Riders who like to find the best apex for the fastest speed through a turn will tend to turn in earlier. As this thread, I believe, is for improved riding on unfamiliar roads the fastest (read shortest) line through a corner is not necessarily the best to take for reading the road ahead.
To increase and prolong the VP it's useful to position the motorcycle as far to the left (towards the centre line for right hand corners) or as far to the right (towards the fog line for left hand corners) as it is safe to do so. This is explained in Motorcycle Roadcraft. Keeping this position through a corner will extend and prolong the VP but it will mean you'll not apex the corner.
This technique, plus 'right gear for the right speed' has helped me a lot on unfamiliar roads for years. Hitting an apex is great for open roads where the vanishing points are a long way off or for the race track. You never know what to expect around the next corner, especially on roads in the Bay Area and beyond...
To increase and prolong the VP it's useful to position the motorcycle as far to the left (towards the centre line for right hand corners) or as far to the right (towards the fog line for left hand corners) as it is safe to do so. This is explained in Motorcycle Roadcraft. Keeping this position through a corner will extend and prolong the VP but it will mean you'll not apex the corner.
This technique, plus 'right gear for the right speed' has helped me a lot on unfamiliar roads for years. Hitting an apex is great for open roads where the vanishing points are a long way off or for the race track. You never know what to expect around the next corner, especially on roads in the Bay Area and beyond...
hobbes
Well-known member
PastRedline
Wanderer
I have a question on this that may seem stupid, but I just want to make sure that I understand.
In my MSF course, and riding with several friends, I was always taught to begin a gentle roll-on as soon as I got leaned in. Not for acceleration but rather to get the weight to the back of the bike.
It sounds like, according to this technique, that if I have a decreasing radius turn, I would end up rolling off the throttle mid-turn (which has always been described to me as a good way to find myself in the dirt, wondering what happened).
Could someone clarify this for me slightly?
Thanks,
Kyle
In my MSF course, and riding with several friends, I was always taught to begin a gentle roll-on as soon as I got leaned in. Not for acceleration but rather to get the weight to the back of the bike.
It sounds like, according to this technique, that if I have a decreasing radius turn, I would end up rolling off the throttle mid-turn (which has always been described to me as a good way to find myself in the dirt, wondering what happened).
Could someone clarify this for me slightly?
Thanks,
Kyle
DataDan
Mama says he's bona fide
Glad to. And it's a good question.
The technique does not recommend rolling off in mid turn. Until the VP begins to recede, you haven't reached the tightest part of the turn. As long as it's getting closer, you continue to slow because you don't yet know how tight the turn is. You need to be able to lean farther if it continues to tighten, so you don't want to be on the gas yet.
When you're no longer closing in on the VP and it is staying a constant distance ahead, you're looking at the tightest part of the turn (see pics 5 and 6 of the photo sequence). This is the key transition. When the VP is at a constant distance ahead you can commit to lean angle and begin to roll on the throttle--as you say, not for acceleration yet, but to stabilize the bike.
Aluisious
Well-known member
I like the first way this is explained in the OP because it's so succinct, common-sense oriented, and everything you need to know flows out of it:
Don't ride so fast you can't see where your stopping point would be.
If people would do that it would fix so many problems encountered in the hills...
Don't ride so fast you can't see where your stopping point would be.
If people would do that it would fix so many problems encountered in the hills...
Underdog
Prehistoric
Actually, rolling on the throttle moves the weight FORWARD not backwards. This allows the chassis to settle down and stabilize.
If you correctly set your entry speed to a turn, you wouldn't ever need to roll off the throttle. If it's a decreasing radius turn, leaning in (WHILE maintaining throttle) will suffice.
Quick comment.
I have always found when the gas is applied it transfers weight to the rear.
Rolling on will minimize the amount, but will help settle the chassis so weight is leveled out/stabilized as noted above.
And it is not true all the time that maintaining throttle will suffice. If you have judged things correctly true.. if you have not then the "throttle on" will force you to lean more to maintain the turn = a more severe lean angle required for the additional speed.
Closing the throttle will apply more weight to the front.. if your not going way too fast the bike should still track thru in most cases. If you are going to fast chopping the throttle late in the turn can put you on your ass...fast.
I find that if you feel you are going to fast, most of the time you can chop the throttle as long as you are not already in much of a lean... and you can still make the turn. This is different on every bike and really best explored on the track.. and is a real moment on the street for new riders and experience a like.
Leaning further than your comfortable with is scary.. but bikes really do go to some pretty decent angles and IMO this is your best chance to make it thru.
Just stay off the brakes.. and hope :angel
:smoking
Underdog
Prehistoric
There are ways of proving that, I'd be happy to supply that claim, K.Code on TwistOfTheWrist has proof as well.
Agreed. These level of freedom interact as said. It's your choice whether you want to lean+throttle or keep your line and maintain throttle. Following the line-of-sight scenario, I assumed you have correctly judged your entry speed based on what you can see. If you find yourself at a decreasing radius turn, you may choose to lean more and add more throttle.
I'd rather not go there. Newbies are often told to use the clutch to slow down when needed.
+1. Sport bikes can lean PLENTY. Much more than you'd ever want to do battle with on the street anyway.
PastRedline
Wanderer
Great answers, guys. Thanks for taking the time to clarify for me.
My understanding is this:
1) Don't roll off the throttle mid-turn (you might get away with it, but it builds bad habits, too quick of a chop and you'll almost certainly have an off-bike experience). The usual advice applies - if you think you're going too fast, lean harder and correct the mistake next time.
2) When used correctly, the VP technique will have you holding a line at the outside of the turn with deceleration until the VP distance goes steady, at which point you should be in more of a maintenance throttle mode, and then when you see the VP start to get further away, commit to a lean angle and roll on.
Please let me know if I seem to have gotten the gist of it.
Thanks again,
Kyle
My understanding is this:
1) Don't roll off the throttle mid-turn (you might get away with it, but it builds bad habits, too quick of a chop and you'll almost certainly have an off-bike experience). The usual advice applies - if you think you're going too fast, lean harder and correct the mistake next time.
2) When used correctly, the VP technique will have you holding a line at the outside of the turn with deceleration until the VP distance goes steady, at which point you should be in more of a maintenance throttle mode, and then when you see the VP start to get further away, commit to a lean angle and roll on.
Please let me know if I seem to have gotten the gist of it.
Thanks again,
Kyle
Bud, this is true if the bike picks up significant speed in the corner. Merely cracking on the gas doesn't result in the bike gaining speed (unless we're in a steep downhill turn). In fact, if the throttle is only open to the setting that would have maintained speed in a straight line, the bike will slow down in the turn because of the increase in friction from the turn against the unchanged thrust coming from the engine. It takes a little increase in throttle just to maintain the speed you carried into the corner. The rider can accomplish this by slowly rolling on the gas through the turn. As long as the speed remains about the same, the lean angle can too, unless the rider must tighten his line.
If the rider does accelerate in the turn, he will need to increase lean angle if he's on a constant radius line.
I think you've misunderstood Keith if you have the idea that rolling on the gas transfers weight to the front. He does not say that anywhere.
What you may be thinking of is what he writes in TotWII, Chapter Three, "Throttle Control, Suspension and Traction." In the sub section "Rear Suspension and Gas," (page 14 in my copy) he describes how the rear suspension tends to rise when the rider is on the gas. This is not a description of weight transfer, it is a description of how the rear suspension behaves when torque from the rear wheel is applied to the swingarm. Under these conditions, the torque causes the swingarm pivot to rise, despite the fact that weight is transferring rearward. This isn't a nitpick; it's pretty important to understand.
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