Thursday, August 31, 2006

Wrapping it up.

Sorry for the delay in finishing this. This week has gone by in a dead run. I taught a beginner's class this last weekend. On Monday I helped teach our advanced class at a track. I have pictures of my scraped sidestand which I will post later. Tuesday night I tried to post but wasn't able to get onto the site. Happens with this host sometimes. It's free to me so I can't complain. Last night I had a meeting of motorcycle instructors that went late. Oh yeah, I actually have a job, too! Thanks for hanging in with me.

In our two-wheeled kingdom, the currency of the land is traction. Most of what we do on a bike requires us to spend that traction. Like any household budget, there's a finite amount available to spend. Sometimes we're richer in traction, sometimes we're not so well off. Our traction expenditures will usually fall into one of four categories. There's 1) driving force; 2) side force; 3) braking force; and 4) traction reserve.

Rule number one for pleasure riders and commuters on the street is:

Thou shalt always have currency in the "traction reserve" account!!

It's not a perfect world out there. Things beyond our ability to prevent happen. By maintaining a reasonable traction reserve we can increase our odds of surviving unexpected hazards. Bear in mind that I'm not talking about being timid. That would be a sure fire way to keep a lot of reserve. It wouldn't actually be safe and it sure wouldn't be any fun!

One area where careful budgeting needs to be done is in cornering. Corners are fun if done correctly. Darned dangerous if they're not. One of my greatest pleasures on a bike is running curvy roads. I suspect that most of you are the same way. Let's go do some corners. It might be a long ride so go to the bathroom before we leave. We're heading out and not dismounting until we're through.

Here's the secret to successful cornering. It's all about setting proper entry speeds. What makes a proper entry speed and how do we know when we've done it?

Let's go back to the Ready-Aim-Fire sequence for cornering. The first two parts are what combine to set the entry speed. During the "Ready" portion we're braking and downshifting if required. This is also the time to move the bike into whatever position we need for entering the curve. Our line will be the classic "outside-inside-outside" path. Which means that for a curve going to the left we would set up to the right. I'm not really going to delve into lines and apexes here. That will come in a later post. Suffice it to say that this line gives us two advantages. It increases our line of sight which helps us see more of the upcoming corner. This path also opens up the turn which increases the traction and suspension travel that's available as a reserve.

So here we are on the outside of the corner. The bike is still straight up and down. What's next? Just the most important part of the whole equation, that's all. It's the HEAD TURN!! We need to look either to the exit of the corner or as far through as we can see. Notice that the "Aim" part comes before the "Fire" step. We need to not only turn our heads but it has to come at the right time. Think about it. What's the number one determining factor as to how fast we can take the corner?

Did you say "our abilities"? Forget about that. My abilities are far better than anyone on the planet. Did you say "what our bike can do"? Forget about that, also. My bike can do absolutely anything I ask of it. What's left? Did you guess "how far we can see"? Ding, ding, ding, we have a winner folks!!

It's critical to "Aim" ( or look ) before we "Fire". That's how we set entry speeds correctly. Looking gives us visual information that tells us what kind of corner it is, what's in it, how the road is, and so on. We set our speeds accordingly. Not only do we need to know if it's safe to "Fire" but we need a target to fire at. That's why I like to use the term "Target acquisition". The bike WILL go where we look. It's a fact of riding.

I hear stories of riders who say they were surprised by gravel in a corner and crashed. According to them, it wasn't their fault. Idiots! If you can't see all the way through the corner what should your speeds be like? If you CAN see through the corner and spot the gravel, what should your speeds be like? If you blindly go charging through a corner without getting good information early and you crash in gravel, whose fault is it? Does any of this make sense?

Riders who crash in corners do the sequence this way: Ready-Fire-Aim. The head turn comes late, if at all. We know this because when we investigate crashes we see that the crash occurs in the last third of the corner. Riders either go off the road and collide with something like a tree or cross the center line and collide with an oncoming vehicle. A lot of the crashes in corners turn out to be fatalities. The sad part is that the riders weren't going too fast for the bike's abilities. Most bikes are far more capable than the riders. No, the crashes happen because the riders were going too fast for where they were looking!! They didn't get critical information early enough. If they knew ahead of time where the end of the corner was going they could have planned their approach accordingly. Blind faith is not a good cornering strategy.

As a side note, I hear this all the time. "Now I know why I ran into the guardrail! ( or fill in the blank ) I was staring right at it". Like I say, the bike will go where you look. It's like your brain is a travel agent and your eyes give it the destination. You look at where you want to end up and the brain says "I can make the body do that". Don't give your travel agent false destinations. You may regret where you end up.

Coming back to wrap up entry speeds, if the following two things happen, you have a good entry speed. Number one, you make the corner. Number two, you are able to have steady or slightly increasing throttle throughout the corner. The "roll" should start before you actually lean the bike. Which means you need to be off the brakes and back on the throttle before you lean. This gives some time for the suspension to recover from the front end dive typical during braking. If you feel like you need to roll off the throttle during a corner you've screwed up your entry speed.

Why the steady throttle roll starting before the bike leans and continuing all the way through the corner? The simple reason is that you will feel more confident and comfortable. You're not worried about braking, leaning, recovering from braking, rolling on, trying to somehow find a target, and so on, all at the same time. There's also some more in-depth reasons. Ready?

Think about what rolling on the throttle does to a bike. The motorcycle pivots vertically at the point where the swing arm bolts onto the engine casing. Rolling on the throttle lifts the motorcycle. More so on the front than the rear, but the whole bike rises. One result is more available ground clearance. Remember keeping something in reserve for those "Oh my God!" moments that sometimes happen to us?

You might not think that's so important. Consider the opposite side of the coin. Here's our intrepid commuter who's either fairly new or has been riding a long time and doesn't understand all the dynamics. We'll call him Happy Harry. Harry's usually pretty good about staying within his limits which aren't real high. That's a good thing. Corners are usually taken fairly sedately so there haven't been any problems so far. One day Harry is extra Happy while riding. There's more of a smile than usual, the day's so perfect for riding, and Harry's boiling over with good feelings. The mood's so powerful that he's distracted from his usual cornering routine. Now Harry finds himself entering a corner faster than he's ever done before. A foot peg scrapes the road.

It's ok. They're hinged. The scraping just tells him he's close to using up his ground clearance. What does Harry do? Being new or untrained, his eyes get big and he rolls off the throttle. Worse yet, Harry brakes. If rolling on the throttle lifts the bike, guess what rolling off or braking does? Yep, it drops the bike. The foot peg is already telling Harry that he's getting close to the end of his ground clearance budget. What does he do? He chops the throttle which puts him into deficit spending. Now hard parts like centerstands and mufflers hit the road. The rear tire is jacked up off the ground which slides Harry off into the ditch. That's called a "low-side" and it's the second least favorite way to leave a motorcycle. Happens to a lot of riders.

A lot of successful motorcycling consists of what I call "un-natural acts". It seems totally contrary to hold throttle when the bike is making these weird noises down there. It seems really odd to not stare at the gravel on the side of the road when we're getting close to running off into it. After all, it's something we're trying to avoid so why not look at it to somehow be able to miss it? How weird is that; to look clear around the corner where we want the bike to end up and trust that it will follow our head turn? These aren't our natural instincts but they better become our automatic habits.

Another advantage from lifting our bikes with the throttle through a turn is increased suspension travel. The lifting action extends the forks and shocks. Which means that they can actually do their jobs of absorbing bumps. If the bike's still in the down position associated with braking or trailing throttle ( remember a bike has three brakes; the engine is the third one ) the suspension is pre-loaded which means bumps can deflect you off course more easily.

Speaking of throttle roll, let's take a quick look at the "Fire" portion. Do you remember the picture in the last post? On the picture it prescribes a gentle throttle roll. Why not grab a big handful of throttle?

Firstly, on some bikes it can be enough to break the rear tire loose from it's grip on the pavement. ( remember "low-sides"? ) Secondly, think about what's going on. Remember, we want to keep traction in reserve, just in case.

What does a bike need to do to corner? Lean and turn, right? What does rolling on a lot of throttle make a bike want to do? Stand up and go straight. Gee, it seems to me like that's the direct opposite of what we want the bike to do. I'm not talking about when we straighten the bike and exit a corner. I'm talking about the time we're still leaned over. If we use a lot of throttle roll it means we have to press harder to keep the bike leaned. It just needlessly eats up traction we might need if some oncoming driver decides to take their half of the road out of the middle, or Bambi goes thrill seeking, etc.

By the way, just in case there's some engineer types out there. Keeping speeds down in a corner is a great way to conserve traction. For any given radius, cornering force is proportional to the square of the speed. For example, if we were to take a corner at 15 mph a certain number of traction units would be required. One could reason that if we took the same corner at 30 mph it would take double the number of traction units required at 15 mph. That would be wrong. Doubling our speed would result in using FOUR times the traction units. Bumping the speed up to 45 mph would require NINE times the units as it would at 15 mph.

What this means for those of us riding on the streets with other commuters or mindless cagers in unpredictable circumstances is that controlling speed is the most important tool we have to manage traction and maintain a useful traction reserve. ( was that a long sentence, or what? )

So there's the long and short of cornering sequence. This isn't all of cornering, by any means. There's still lines, apexes, and strategies to consider. There's subtleties of how to use the throttle to our advantage during a corner. Yes, sometimes a slight roll-off under controlled conditions can actually be our friend. As can rolling on a little more during a corner. This is a start. I hope it helps. Check out your own cornering and see if there's room for tuning things up. Be safe, but don't forget to have fun. Actually, you will have more fun because you'll understand cornering better and feel more in control.

Miles and smiles,

Dan



5 comments:

dan_durham said...

I've heard of riders who have improved their technique with nothing more than the head turn and have nearly run off the inside of the track at their usual speed because their cornering is so much better.

Personally, getting the head turn and look technique down helps all the rest come more naturally for me.

Thanks a million for sharing this moto-wisdom!

-Dan

irondad said...

dan,
Head turns are a great key to success. I was just reading a letter to the editor in Rider Magazine. The author said that they had lost 10 riders in corners in the last while.
Just wanted to share some of my experience in the hopes it makes a difference to someone.

Dan

Krysta in Milwaukee said...

Your fable about Happy Harry and his low limits reminds me of a guy I saw last week on his Harley.

Two lane road, no-passing zone both directions, starting up a hill, and in order to make the right-hand turn (to maybe 2 o'clock) he swings over to the LEFT fog line (across the double yellow & the oncoming lane - just to make that clear), then leans back to the right just the little tiny bit you can actually lean a Harley before scraping chrome.

It was one of those times I really wished I could write someone a ticket. Or better yet, take away his license and keys on the spot.

irondad said...

krysta,
you might have done him a huge favor had you been able to end his riding career!

Anonymous said...

Great stuff, Dan.

Not to nitpick, but with conventional chain drive, the rear end of a motorcycle squats during acceleration. Shaft drive bikes and scooters (with engines mounted on the swingarm) lift during acceleration.