Caveat, Warning, No Guarantee
This node / wu reflects the
author's experience and choices. It will contain
mistakes and omissions, while it endeavours to attain
accuracy and convey
ideas intended to help avoid
injury, the subject of
motorcycle safety
is a large one. The views stated here are not written to
thrill novice
riders or convey
bravado.
I will maintain this node to the best of my ability and work to
incorporate other views into a lucid whole. I would love to see additional
writeups here.
Please consider reading all of these first: Motorcycling tips Motorcycle
Safety Motorcycle Safety Foundation How to stay alive on a motorcycle
how to kill yourself on a motorcycle How to be a good motorcycle passenger. I'm assuming, we all know how to countersteer, look through to the end
of a turn and always be shifting focus to the current danger.
Intro
That out of the way this node is intended to convey some (
advanced?) techniques
I've picked up in the admittedly
few years I've been at it (ca Aug 2002: 5
years / 50,000 miles). I live and mostly ride in a
city (
Boston)
well known for it's poor driving conditions, this influences what I've learned
and how I ride.
Which is to say pretty hard. I have no qualms about learning the limits of
what the machine and rider can do in relatively controlled
circumstances. For the record I have dropped each of my (3) bikes, a few dozen
times in all. I have lowsided perhaps 3 times, highsided twice,
had a bike spin 180° on black ice (no fall that time) and suffered one
severe accident, the result of a limousine driver running a stop sign.
I've also recovered from a couple of front-wheel skids and kept myself and
my pillions safe in some scary circumstances. If your philosophy or
objectives differ, these ideas may not be a good fit, but maybe this will be
useful input anyway.
So why the hell would anyone care to read what I have to say about riding
technique? Well, MSF won't say some of this simply due to liability concerns
and others may have different viewpoints. I've read many books and websites
which may convey extraordinarily good information for someone riding a
goldwing that could be hazardous applied to a sportbike. Some of the points
I will make will differ from MSF, and other experts. That is why this node
exists, not to display truth but a different view.
Some often stated "Facts*" which are wrong
- * A bike can stop nearly as fast on wet pavement as dry
- -- In an MSF course with no oil on the pavement? true
- -- on a wet street with oil from traffic? no way.
- * Available braking force is 80% front wheel, 20% rear.
- -- A modern sportbike develops max braking with the rear 1/8" off the ground (100:0 ratio)
- -- Cruisers may skid on the front wheel with 40% or more of the weight still on the rear
- * Braking with the front wheel (especially in a turn) is dangerous
- -- Absolutely, however it is possible to recover from a front-skid
(Iff you're straight up, in a turn or non-level road the probability is small)
- -- and there are times when you want to use your front brake - even in a turn
- * Keeping a machine in tip top condition is essential
- -- This one is absolutely TRUE, Ok, no machine is ever quite as perfect
as we like.
- -- When attention is compensating for equipment in poor fettle, it's not on riding
- * Cage drivers aren't expecting to see motorcycles, therefore they often don't see us
- -- This means you have to see them. Not liking that is a good way to get hurt
- * The cage drivers are *not* always responsible for accidents
- -- And many riders belief that it will be the other guy's fault begs the question
- * Look where you want the bike to go, not at the hazard!
Some experiences and Ideas
Generally, as all the books will tell you concentration is your primary tool
in staying alive on a motorcycle. Even when riding a straight road, crossing a
few hundred miles of desert, riding is not the time to be thinking through
some problem at work, or replaying lastnight's argument with your
SO.
Making eye contact with the cage drivers is an essential skill, even with
your (clear) visor down, you'll be amazed how quickly that will get the
attention of someone who was about to fail to see you. As an aside I think
those really cool looking mirror and shaded visors are a very good way
to help other people not see you.
Story:
I purchased my Ducati* (St2) from a fellow who mostly rode a Harley and it
showed. The rear brake disk was nearly worn out in just 10k miles and the front
disk pads were barely worn. I think that's a pretty classic case of a guy who
was overly afraid of a front-wheel skid. This is a bike on which I've had the
rear end come off the tarmac with full touring bags mounted, total load of
100 lbs of gear in the rear & tankbag.
When riding straight and the pavement is not much cambered, loss of front
traction due to braking too hard can (sometimes) be recovered by letting go
of the grips, most bikes will shake badly through a couple of oscillations
and then recover. During the first month that I was riding (the Commando)
I intentionally locked up the front on wet pavement and recovered (somewhat
shaken).
Current technology bikes will perform beyond nearly all rider's skills. It did
not take me too long to feel like I had gained a solid understanding of the
limits of a 25 year old Norton. Even with the best tyres available, the
limits of traction aren't usually enough to generate a stoppie or to ever
consider dragging a knee and pushing the throttle moderately hard in
2nd (let alone 1st!) in a turn will surely cause the rear wheel to slide a bit.
Conversely, one spring morning, 2nd gear leaning thru a corner on the Ducati,
I rolled on a healthy bit of throttle, and was amazed to find the front
wheel lift just a bit off the ground and smoothly regain traction after
stepping out what felt like 2" off it's line of travel. That would have been
very bad on slick pavement, but it gave me a pretty good feel for what the
bike's capable of. I think the Duc is about capable of full race angles
on clear pavement, and I don't want to be anywhere near that level of
edge play on the street.
Balance
An important part of keeping your balance on a motorcycle (as with a
horse)
is to hold your mount tight with you knees. You don't want to be doing this
continuously for long rides, still keeping a sense of contact with the bike
is helpful even on long - straight rides.
By the way, I have come to the belief that kicking out a knee is an excellent
balance technique. Basically when you shift your upper body the mass is
distant from the contact patch, requiring a motion of the bike in the
opposite direction to maintain stability. However if you move a mass that
is closer to the ground you get less moment with respect to the contact
patch and thus you can shift the bike's balance more effectively with your
legs than upper body.
Some things I think I've learned
- * Relax. riding tense just causes fatigue This goes for mind & body
- -- You want to be aware of everything, focusing on one thing is not good
- * Anticipate what *might* be coming
- -- In winter you may enter a turn with ice in the apex you had best be ready to straighten out
- * Hanging off* is not a good idea except on the racetrack
- -- Dragging metal on the Norton *and* hanging off for an extra bit caused highside 1
- -- Leaving a margin for error matters
- * Fatigue really hurts judgement, and the ability to recognize the impairment.
- -- Learn to recognize it.
- * Riding fatigued & fast is the surest way to dumping a bike I know
- -- I suspect most of us learn this one the hard way
- * Riding at high speed may be safe; it also rapidly fatigues the rider
- -- Two of my minor dumps immediately followed 2-3 hour stints of high speed
- * You don't have to be going very fast to get badly hurt
- -- When that limo ran the STOP sign in 1.5 sec. I got the bike down from 35 to 10 mph
- -- It still cost a the PCL ligament and cartilage damage to my knee
& a $12,000, 3 hr surgery
Fatigue and other impairments
Fatigue is a form of impairment, you have to account for it just as you would
if you had one or more beers before riding (I'm not advocating that riding
under the influence is OK, but it makes little sense to pretend it never
happens either).
Realistically, people ride at times when they're not in top form, be it tired,
angry or otherwise pre-occupied. As indicated above, fatigue seems to be
especially insidious. Just eaten a highly spiced meal, or had sex? Trust
me the endorphins generated make you as surely stoned as if you'd just taken
a couple of hits off an opium pipe. Be sure to adjust your riding to
accommodate.
Road, wind and machine noise all cause fatigue, as does heat or cold. This
is the reason you really don't want to try to ride 250 miles with no stops.
A number of things will help; Shifting your stance on the bike often, staying
hydrated, and adjusting your clothing before you take a chill or overheat.
The concentration needed for riding is also more fatiguing than what's safe
for driving a cage. This dictates that when methods above reach their limit
your attention will start to wander. You probably wanted to take a rest stop
30 minutes before that.
Two very important impairments are hypothermia and dehydration / overheating.
When your body temp. drops (or elevates!) your higher brain functions are
the first casualty. I wear full gear for riding in deserts. Pulling off the
leather in 100°F will cause your body to lose fluids much faster, possibly
faster than you can replenish them.
Margin for error
Nearly all discussions of riding safety mention this and with good reason.
So for instance while getting a
feel for the benefits of
hanging off
to lower
center of gravity is a good thing, I've found its a poor strategy for the
street. You may choose instead to lean the bike a little more and perhaps
even lean your self a little less (very good tactic in tight / low speed
turns).
Now, if the rear breaks out you can easily push your body down,
let the bike actually come up a bit and you will probably recover. In fact
this amounts to hanging off, but not until you need it. Also I think
you'll find that your body and the bike form a nice pivot, that is a
degree of freedom you can use to stay out of trouble. If all of that's
not reason enough, remember that your tyres (at least on a sportbike) are
designed to use the tread all the way out to the edge, so leaning the
bike a little more and you a little less should make for more even wear,
as well as keeping the sides scrubbed.
An addendum, I believe the reason that this works especially can be
seen by looking at a diagram. We assume that
ceteris paribus the composite
CG of the bike+rider need to stay at something like a constant location,
Big changes in this are bad (require additional steering / acceleration
inputs which in turn cause further loss of traction!)
######
##########
############# <--- 120-200 lbs
############### rider body
################## (hang-off position)
### ## ### ### #
Pivot point ---> ### ~~~ # ###
### / \ ###
### / ###
###/ / ###
##/ / ###
#/~ / ### <--- 400-500 lbs
/ ~/ ### Motorcycle
/ / #####
/ /
/ /
\__/ <--- turning force
---------------------------------------------------- <-- road surface
normal force --> ^
|
contact patch
Stick figure versions
A ---> B
* -rider CG- *
/ |
/ | <----- Pivot point
| /
* -bike CG- *
| / Direction of turn
| / ----->
| /
-------------------------------------------
A <--- B
| Gravity force
↓
-
What happens when the (usually rear) wheel loses
traction?
The rear wheel slides out a bit, causing the bike & rider CG to drop
(think free-fall in the event of a low-side). What are the options for the
rider to maintain balance and recover traction?
Steering into the turn would simply increase turning force cause further loss
traction. The usual correct answer is steer into the direction of slide and
slightly roll on throttle.
The available degrees of freedom are:
- steering input
- braking (front or rear)
- throttle (increase or decrease power to rear wheel
- composite geometry (i.e. rotate at the bike-rider pivot point
So, what happens in the two boundary cases of initial rider position,
A and B? In each case the bike rotates about it's CG
- A->B This rotation about the CG has the effect of momentarily
reducing normal force at the wheels. -- This is bad
- B->A This rotation momentarily increases normal force at the
wheels, and can help the rear wheel to re-attach.
To maintain the balance vectors composite CG needs to remain stable
and so corrections need to be made in a combination of steering / weight
shifts.
The usual advice for a rear-wheel skid is that you need to ride it out
to a stop or straight & level to avoid a highside. And this is correct
once the rear wheel has made substantial progress, or if the skid is
due to application of the brakes in which case it's locked. The instance
where the rear is still turning is where riding stance can help you get out
of trouble.
Because the bike has substantial inertia, at the moment the wheel begins to
lose traction, if you can regain traction you win. This is where using
the pivot point between bike and rider is essential and that's a very good
reason to avoid hanging off when riding on the street.
Notes:
* Ducati: Learning to ride this bike which is quite happy to lock the front
wheel with a firm grip of 1 finger was quite the experience in humiliation.
Having learned to ride on a bike that needs very strong hand pressure
on the front brake my 'normal' reaction was sure to drop the bike in slow
maneuvering turns.
** Hanging off: In a turn, where the rider slides his butt and body to the
low side of the saddle, thus lowering the CG and allowing the bike to be
steered through a smaller (or faster) radius turn.