Two SLLR questions

[saizai]

I know the usual advice and try to practice it; I want a couple specifics.

1 - look

Take your prototypical freeway onramp. Call it a right-hand turn, 270 degree, decreasing-radius, with the wavy steel barriers on both sides.

At entry point (on the left side of my lane), I start to look... where?

a) as far right as I can, aiming for the exit window 270 deg. to my right (i.e. full stop headturn when entering and for most of the turn)
b) at the air above the rightmost piece of asphalt that's on my line, but still within view
(i.e. - the barriers or whatnot of the turn cut off my view; aim for that part which I *can* see, but I know is on the line; this continuously "slides" along until I'm basically out of the turn. Would also mean that head turn increases [rather than staying static] when the radius decreases)

B is what's comfortable for me - I don't like looking past the area that I can see the ground, 'cause it means I have less perception of that part that's cut off by the barriers or whatnot.

Note that I'm only asking in the context of a 30mph+ turn with not all of it visible, not for slow-speed U-turns or moderate ones where you can see through the full turn.

I want to know if this is something I should train myself out of (and into version A), and if so why.


2 - roll

Exactly how much do you accelerate through the turn?

Suppose you're on your favorite chunk of twisty road. Speed limit posted is 40; turns are marked at 25. You're riding my Ninja 250. Conditions are expected to be normal (i.e. you haven't pre-cleared it; possible hazards per usual; no rain).

What are your speeds / revs at:
* middle of straightaways
* entry of a turn (before intiating turn proper, after braking)
* actual apex of the turn
* exiting the turn

Does this change significantly depending on the type of turn (blind, S, etc) - if so how?

When riding with a buddy, he suggested that I wasn't accelerating enough - but that in turn seems to imply to me that I wasn't slowing down enough *before* the turn. So I'd like to have some real numbers for comparison.

Thanks!

- Sai

 

[argh]

My opinion is that you should be looking where you're going to be in X seconds.

If the road X seconds away isn't visible, then you should slow down to the point where the road in X seconds is visible.

Same principle as not outriding your headlight.

X is based on your own skill level. If you can't react to something bad in the road within, say, 70% of your skill level at X seconds, then you need to increase X.

If you can react to stuff in X seconds but you need 99% of your skill to do it, you're going to get bitten someday when you're only riding at 90%.

Sorry to be vague, but while yes, the bike will follow your nose, the idea isn't to blindly look at the hilside blocking the apex because that's where you would be looking if the road was flat. Get out towards the center a bit more to increase your sightlines (and visibility) and slow down.

Part B - you should enter the turn at a speed that lets you roll on the throttle comfortably throughout the entire turn. It is much better to go in slow and come out fast than it is to go in fast and come out dead.

There are no numbers. There is no speed where you "should" do it. That's a game that will just get you hurt.

Do it at some speed. Did it feel slow? Speed up. Did it feel fast? Then it was too fast. Period. The perception of speed is your brain telling you that it isn't keeping up with the sensory input, and is getting overwhelmed.

Figure out whether you're limited by physics or technique. You can fix technique. Physics is harder and more unforgiving.

 

[saizai]

Part b - I know the "entry speed = speed at which you can roll on throughout". The question is - roll on how much?

Take two profiles:
#1 (shallow): Start at 40. Slow to 30 before curve. Accelerate to 40 by the end.
#2 (deep): 40-15-40.

Both have you going the same max speed through the turn - which seems like the main "did you take it too fast" measurement. But they result in having pretty different amounts of *acceleration* / roll-on, ya?

I've been successfully keeping my max speed within my limits (and well below what I know the bike to be capable of). I'm trying to figure out how *much* I should be accelerating through the turn.

(Obviously, I'd modify others' numbers down to match my max cornering speed - that's why the extra ones are there, so I know what their relative baseline is for that.)

 

[argh]

There is no "should".

A slower entry speed will require less of the available traction, let you use a smaller lean angle, and provide a larger margin of safety. A faster entry speed will require more of the available traction, a sharper lean angle, and provide a smaller margin of safety.

Valentino Rossi could probably enter your "40mph corner" at 60mph, and accelerate out to 100mph by the end. You're not Valentino Rossi.

Your question is somewhat like asking "how many knives can I juggle?" It depends on your skill level and how much margin of safety you want to leave for youself. Both of your scenarios (40-15-40, 40-30-40) have their place.

Simple physics sez that even without slowing down before the turn, you will need some additional throttle input in a turn, or else you are decelerating. Rolling on the throttle stabilizes the suspension, and gives you more clearance.

Even if you can make it through with an entry speed of 30mph, how much of your skill level is that taking to do it? If you suddenly spot a sandy spot mid-corner, will you be able to avoid it?

Higher entry speeds can be fun. So can rolling on after a slow entry. Risk, reward, personal choice. (My personal choice is to go for "smooth". Have you read The Pace?)

edit - revised wording about available traction per Enchanter's correction.

 

[saizai]

Haven't, have queued for reading....

 

[Enchanter]

You sould look as far ahead as you safely can. If looking 270 degrees through a corner dosen't work for you, don't. At a minimum, I would look to what many riders refer to as the 'vanishing point' of the curve. Look to where the road disappears. And as has already been said, don't worry about what your speed should be. Enter a turn at a speed that is well below your stress level, then gradually roll on the throttle. Investigate the possibility of riding with some other (skilled) riders. This will give you a point of reference.

The following quote is a misconception:

A slower entry speed will give you more traction,

For any given situation, traction is constant. You do not get more traction by using a slower entry speed. The inverse is also true: you do not have less traction by using a faster entry speed. A slower entry speed help because you will use less of the total traction available to you. This means that there is more left over for an unforseen situation such as a midcorner steering correction due to debris in the original path of travel. A street rider should ride in a manner that leaves some traction left for an emergency technique, should one be required.

 

[saizai]

Enchanter - it's probably more of a misstatement. "More traction available" is what I interpreted it as.

And yes, of course on the keeping a buffer for extra measures, and trying to be smooth. That's all mutually agreed on easily.

How about a rephrase of the question, then:
What will be different (pro/con) about slowing WAY down before a turn, vs only slowing enough to have minimum roll-on throttle throughout, assuming the same peak speed?

 

[Enchanter]

How about a rephrase of the question, then:
What will be different (pro/con) about slowing WAY down before a turn, vs only slowing enough to have minimum roll-on throttle throughout, assuming the same peak speed?

Hmmm...

The more intense the accelleration, the more traction used.

A very slow entry speed will use less traction than a higher entry speed until the (comparative) speeds are the same. This is assuming that the rider is not aggressively rolling on. Be smooth, gentle.

Also, if you slow down more than the traffic behind you expects you to, that brings on a whole new set of problems.

 

[saizai]

Wouldn't that argue towards using more minimum acceleration throughout, so as to use up less of your total and have more available for turning / emergencies?

 

[Enchanter]

Wouldn't that argue towards using more minimum acceleration throughout, so as to use up less of your total and have more available for turning / emergencies?

I'm not sure that I understand the question.
If I do: Slowly applying the throttle will use less traction than rapidly applying the throttle.

It is possible that inappropriate use of the throttle can overcome the traction available regardless of the speed of the motorcycle at the time.

 

[saizai]

Do you mean "smooth" throttle as in "not choppy", or as in "not in quickly increasing amounts"?

They're related, but different. Smooth the former is obviously always a good thing. But you can have smooth but very strong acceleration also...

 

[Enchanter]

It wasn't clear. Sorry. I fixed it to be more clear.