Aug 15, 2016

#130 Sliding to A Stop

All Rights Reserved © 2013 Thomas W. Day

I was exploring some of the dirt roads between St. Paul and Taylors Falls on a Saturday morning this past fall, when I had the occasion to come to a couple of emergency stops. The first time was after a short series of 15mph turns on a paved farm road, I was barely out of one of the turns when a large deer wandered into the road and stopped to observe my on-coming motorcycle. He was in the middle of my lane and, since a truck was coming the other direction, the only evasive maneuver available to me was a quick stop. I've read several reviews of my WR250X that implied that the brakes are "weak" or "mushy." I beg to differ. Maybe for a racer's tastes those descriptions are apt, but for my weekend warrior playbike purposes the WR stops just fine.

And it did.

A few years back, I managed to execute a similar maneuver at night on a mostly-empty highway on my 650 V-Strom. For the most part, that incident had a happy ending, too, other than getting me gore-coated when an opposite-direction pickup splattered the deer all over his truck, emptying the contents of the deer's bowels all over me in the process. That incident taught me not to admire the luck and skill of an emergency braking maneuver for more than it takes to pick a safe path around the deer and get the hell out of there.

One of the best things about being a motorcycle instructor is that I have to demonstrate quick stops a few times every week and think about braking technique often enough to be able to explain and do it half-well. Too bad there wasn't anyone around to see this demo. I squared the bike up and laid into the brakes right up to the front wheel's limit of traction. I might have slid the back tire a little bit, but not much. The deer wandered off of the road, after getting his day's entertainment out of my emergency, the truck roared past without making any sort of adjustment, and I got the hell out of there and went back to playing around on the backroads.

A few miles further from that encounter-of-the-hoofed-kind, this time on a gravel farm road, I crested a hill and discovered a freakin' herd of deer parading across the road; big ones, middle sized ones, and at least a half-dozen little bitty Hell spawn Bambis.  This time, I was moving a bit faster and hauling the bike down to stop took a bit more concentration. The road was slightly damp, covered with loose gravel and small rocks, and provided reasonable traction. No harm no foul or fawn.

After the four-hoofed crowd meandered from the road and I got back on the trail, I thought about how my two four-hoof experiences could have ended and how a police investigator might have evaluated the "evidence." When I read police reports of crashes, one of the bits of "evidence" they seem to use is the skid distance left by crashed vehicles. Supposedly, this is some sort of indication of how fast the vehicle was traveling. Using that useless data point, if I had hit the deer the cops would have claimed I "made no effort to stop." No skid marks, no braking? Seriously? I thought about this for a while after the last stop. On wet gravel just over a hill and no sliding and the bike came to a quick stop a good distance before any of the hoofed rats or me were in danger. So, no evidence left for the highway forensic "experts" to interpret and that would tell them what about my riding ability, attempt to avoid the collision, or anything else?

A while back, there was a news report about an off-duty cop who ran into a kid in a residential neighborhood  after "laying the bike down" in an attempt to avoid the collision. I see that kind of language in local police crash reports, too. We talk about this silly stuff in motorcycle safety classes all the time. Anyone who believes that sliding on polished metal provides a better coefficient of friction than rubber probably shouldn't be playing with motorcycles. The only time I have ever seen a sideways motorcycle stop more effectively than one still operated rubber-side-down has been in soft, deep sand or sloppy mud. Often, that tactic results in a spectacular flying machine stomping the crap out of the helpless rider. Stopping or slowing quickly in either one of those situations usually involves flying over the bars and some unpleasant impact activities, followed by a completely out-of-control motorcycle doing whatever physics and luck dictate. Pavement requires some kind of sticky material for traction. Conveniently, tires are made of sticky materials. Bodywork, chrome and painted bits are considerably less sticky. 

"Lay 'er down" logic ranks up there with the "Loud Pipes Save Lives" insanity. The argument defies logic, physics, mechanical engineering, experience, reality, and statistical evidence. Motorcyclists know that dropping the bike is an out-of-control panic maneuver, usually due to inappropriate rear brake use. Bikers never get good enough to know the difference. If you don't know which kind of rider you are, you are not a motorcyclist.






2 comments:

Paul Compton said...

There will be plenty of evidence on the road surface, even from braking well short of the limit of grip. Loose particles will make short marks as they're moved by the longitudinal compression and expansion of the contact patch and rubber itself will be lain down on the road surface. In many cases, those will be the 'skid marks' being talked about.

Thomas Day said...

"Plenty" is clearly a relative term. I think you are overrating both the competence, interest, and awareness of the people (at least in the US) who do crash analysis. We have a hard time getting our cops to note if a motorcyclist was wearing a helmet; and other protective gear isn't given a second though. Hell, from my training experience I've found that most of our cops who also ride are as anti-helmet as the ABATE characters. While I agree that under good conditions there might be some available evidence that competent braking occurred in a crash, I disagree that what passes for police in the US have the competence to make that analysis. I've watched several crash scenes (in California, Nebraska, and Minnesota) being worked and if there isn't a black strip to measure the cops are clueless.