Saturday, March 10, 2007

Braking in a curve.

I guess if I’m going to hang out in this neighborhood I might as well make myself useful.

A couple of recent posts have been about braking technique. Most of the discussion’s been about braking in a straight line. A large share of the braking errors that lead to crashes happens in that scenario.

Emergencies don’t always happen while riding in a straight line, though. Not too long ago Katie and I were winging around a corner on Scenic Drive. The picture above shows the curve. You can’t really tell from the picture but this road goes uphill from where I’m sitting when I took the picture. There are several sharp corners and the sight distance is a little limited. On this particular day we were actually coming down the hill. You can see in the other picture how much brush is alongside the roadway. It will be worse when Spring fills the trees with leaves.

As we were coming down the hill I noticed a utility truck on the side of the road. It was parked in the wide spot ahead of where I’m sitting. You can see the corner of the bike’s windshield in the picture. As much as possible I’m keeping an eye on the truck. I’m always looking for clues. Front wheels provide great ones, as does the body language of the driver. It would be too much to hope for that the driver would actually signal, I suppose. So I try to take care of myself. With absolutely no warning the driver made a dive for the side road you can see in the picture. The problem with big rigs going uphill is that their forward progress takes a while to happen. Kind of like vultures trying to take off. Don’t ask me how I know.

All I can say is that a kid who thought it would be fun to scare a bunch of vultures around a dead cow got a huge surprise. My dirt bike hit the middle of the flock a little while before they could get airborne. Ask a few of your friends to beat you about the head and shoulders with pairs of three feet long bony feather dusters. If they are any kind of friend they’ll be happy to oblige. You’ll know what I felt like. Gleeful mischief quickly turned to pain. Oh yeah, I forgot to mention one other little thing. In order to get more lift these birds lighten the load by dumping unspeakably nasty ballast.

So here I am, heading for possible disaster. To make matters even worse, I have my soul mate on the back of the bike. Being the calm cool, competent professional that I am, my first words were,

“Holy crap!!”

Expressive, but not entirely helpful in this situation.

Emergency braking in a corner is a whole different exercise than when in a straight line. It’s the kind of skill you never need until you need it, if you know what I mean. Then you REALLY need it. Be honest. How many of us actually practice skills like this on our own for the times we need it? I have an advantage because I teach this stuff all the time. It’s always fresh in my mind. Would I do it as an average rider? I would certainly hope so. But there’s a good chance I wouldn’t, either. I can tell you for sure that I never did prior to 1987 when I finally took the Experienced Rider Course. I was lucky I managed to skate an examination of my missing skills for so long.

Taking it a little further, does the average rider actually know what technique to practice in the first place? I’ve encountered a lot of so-called “experienced” riders who really had no clue. Eventually they’ll face a critical situation. It might be another ten years. It could also be within the next few minutes. They’re going to just have to take their best guess. Will it be the right one? Even if they have a clue, has training and practice been enough to make their habit overcome their first instinct? In this case, a human’s primal instincts will probably work to their detriment.

My mind’s quickly weighing the situation. How much room do I have? Can I straighten and brake while staying on the road? You can see in the picture that there’s not much room. I’ve already planned on a late apex since the visibility through the corner is restricted. I’m pretty close to the outer edge of my lane already. Will I have to brake while leaned over? How much traction am I using in my lean? How will the gravel in the curve affect me? Heading downhill is preloading the front tire already. How much more can I ask of the front tire? With the added weight of my passenger will the back brake be able to do extra duty?

I’m pleased to say that I was able to stop in time with no harm to any parties involved. Understanding the dynamics involved will go a long ways toward saving a rider’s hide in an emergency. Not to mention a perfectly good motorcycle!

Just like our local money’s the currency of the land, traction’s the currency in riding. Similar to the small amount of money that comes my way, traction’s got a finite limit. There’s only so much currency available. We divide our total budget into smaller accounts.

If I had to name a few major expenses in our household, they’d probably look something like this:

Housing: Rent, house payment, taxes, utilities, etc.
Food and supplies: All my household stuff.
Vehicles: Bike stuff at the top of the list, of course!
Savings: I’ve heard of this but haven’t actually managed to have any.

These things are always fluid. Some months bring greater demands in one or two areas and less in the others. Next month it might be just the opposite. Summer brings a little more money to our budget since I teach a lot then. Winter’s a little leaner. Either way, I can’t spend more than my total available funds without being in big trouble.

Traction works the same. There’s a set limit at any given point. Some days the available resources are higher. Some days they’re lower. Either way, I can’t overspend the current limit without dire consequences. Here’s what the main categories would look like for traction accounts.

Driving force: Anything that propels the bike forward
Side forces: Pretty much any time the bike’s in any position other than truly perpendicular
Braking forces: Anything that wants to impede the forward movement of the bike
Traction reserve: You do try to keep some traction for those “pucker” moments, don’t you?

What really makes it interesting is that the demands of each account are always changing. There’s no way to really get into a single pattern that works all the time.

Next post we’ll talk more about managing these separate accounts when braking in a curve. Stay tuned.

Miles and smiles,



American Scooterist Blog said...

You've got me hooked. I want to know what I don't know. Although I've been riding the last twenty five years (legally street)I gotta find out if I'm missing something. I bet I am. Please post this soon as even here in central Minnesota it is warming up.

Harv aka The Roadbum

Bill Sommers said...

I clearly remember using the same "Holy crap" quote last summer while on a tight left hander and finding a rock about the size of my helmet in front of me. Rather than cutting the corner into the other lane, I "floated" right and drifted out to the fog line before I could pull back to my line. I puckered tight on that one.

Good lesson neighbor.

Have fun,

Steve Williams said...

Sign me up for the online course too! I know from the MSF course that they told me to straighten and brake. They didn't say anything about what you do if there isn't room to straighten or if a vehicle is coming the other way.

Like Harv and Bill I'm anxious to do something about the things I don't know.

Steve Williams
Scooter in the Sticks

Anonymous said...

next post? stay tuned?

what is this, the teaser for the 10:00 news?

Good Lord man! What if I need to brake in a curve on the way home today?

Fortunately for me, there was a tight and steep downhill curve with a stop sign at the end on the way to my Basic Rider class last year. I made sure I asked the MSF instructors a questions about that one.

Combatscoot said...

The mini-story about the vultures had me rolling. I've had a few near-misses with such vile critters, and can imagine an encounter with a flock of them.

Irondad said...


I didn't expect to have to wait quite so long to post the next part. Actually, the acute interest took me by surprise!

Today is Wednesday. Look for the post late this afternoon or this evening. There will actually be two posts. This kind of stuff gets involved. I will change the date so that the posts look like they were done on two different days. That way I can put them both up at once.

The vultures were a real trip. It's funny now but not back then.