Motorcycle Tips & Techniques

Motorcycle Safety/Dynamics

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Safety Tips

Over the years I have written hundreds of motorcycle safety related articles for publication on my website and for various newsletters all over the world.  Here are 277 of those articles for you to spend a long evening considering.
     Safety Tips

        (Found 27 Tip Articles.)

   
Tip007: Dumping A Bike Is No Sin
... me. You can use a flat solid surface, such as a LARGE piece of cardboard and place one edge at the contact patch of both tires then see if anything other than your fold-up pegs and engine guards touch that surface. If so, it can hit the ground when you d...
But ending up under it is  Size:       20kb.

Tip048: Counter-steering
...at you. (The body of the motorcycle remains pointing to the right.) You will now recognize that the contact patch which was B before the wheel turned has now got to be near where C' is at. In other words, the fact that your wheel is on a rake results in t...
Not the least bit as simple as it feels  Size:       45kb.

Tip060: 'Under-steering'
... out of a curve that under-steering provides.]But then you notice that your rear tire has a greater contact patch than does the front (at least when riding vertically.) You might assume that because of this it has a higher Coefficient of Friction with the...
Not the same as 'slow-steering'  Size:       20kb.

Tip076: Slip Angle
...an deform in four ways: Radially - (from side to side) - like the bulging in the sidewall above the contact patch. Circumferentially - like the way the sidewalls wrinkle in soft drag tires when accelerating. Axially - a deflection that tries to pull the t...
Beyond Counter-steering  Size:       29kb.

Tip173: Slow Speed Or Shortest Radius Turns
...re precisely, the radius of the turn is the distance from the center of the turn to the CG, not the contact patch. So, your wheels would describe a larger turn with a larger lean if you have the same radius.)So just what part does the height of your Cente...
A bit of geometry shows you how and why  Size:       30kb.

Tip247: Path Travelled
...eed, there is a difference between the direction the wheel is pointing and the direction the tire's contact patch is pointed. In addition, whenever you input a steering angle other than straight ahead, the contact patch slips a little as it attains the ne...
(Not at all obvious)  Size:       28kb.

Tip255: Another Retread Has Trouble With Counter-steering
... look at what's really happening with a more critical eye. [Think of centrifugal force pushing your contact patches to the outside of the turn instead of the top of your bike.]When you make a turn it is your perception that you are leaning the top of your...
... And Believes that the MSF's BRC is a 'Safety Course'  Size:       39kb.

Tip256: Neutral Steering
... rear with the bike absolutely vertical and with zero steering angle. Note that the center of their contact patches is in the dead center of each tire.Now we roll (lean) the bike over to the right by 30 degrees and maintain a zero angle steering input. (I...
(Fact or fancy?)  Size:       45kb.

Tip001: Highside Dynamics
... traveling. Since the bottom of the rear wheel has stopped sliding, (all stopping forces are at the contact patch), clearly a torque is developed. The result is that the bike is violently twisted in the direction of the earlier slide. The front wheel actu...
What happens and how to prevent it  Size:       39kb.

Tip035: Hydroplaning Issues
...la that is somewhat more accurate, though much harder to calculate, is: 7.95 * Sqrt(tire pressure * contact patch width / contact patch length). This formula shows that the wider the contact patch is relative to its length, the higher the speed required t...
What is it? What to do about it? Are they making new tires less safe?  Size:       24kb.

Tip089: Hydroplaning Avoidance
...re sidewalls.The reasoning behind this suggestion is simple: Increasing the tire pressure makes its contact patch smaller. In other words, it increases the weight per square inch of the contact patch so that it takes more 'uplift' by water to cause hydrop...
Tire air pressure  Size:       14kb.

Tip164: Speed Bumps And RR Crossings
... front-end of your motorcycle. [A quick review ... Trail is the distance between the middle of your contact patch and that point on the ground pointed to by an imaginary line running through your steering stem. It is created as a result of rake angle, off...
Why they can dump a bike  Size:       19kb.

Tip270: Crossing Railroad Tracks
...EGATIVE TRAIL' is and does? When your tire rides up onto a bump, like a train track, as soon as the contact patch lifts off the ground level it had been traveling and into the air, trail has become substantially smaller and often becomes negative. Negativ...
Attack Angle?  Size:       31kb.

Tip030: Taper Braking
... ratio cross-plies). The usual tread pattern was ribbed front and block rear. And the all important contact patch was long and thin - not least because the wheels were 20" or more in diameter.But above everything else, it's the design of motorcycle frames...
Why 75%/25% is incorrect  Size:       36kb.

Tip091: Locked Brakes
...% as soon as you start sliding. This, in part, because a sliding tire generates so much heat at the contact patch that the rubber there begins to liquefy. [Actually, dynamic coefficient of friction is always lower than static coefficient of friction.] (Cu...
Sometimes (rarely) this is the fastest way to stop  Size:       19kb.

Tip192: Rear Tire 'Chirp'
...es defined by your swing arm and the top of your chain (belt). If you draw a new line from the rear contact patch to that point you will have defined the 'chain angle' of your bike. This is shown as 'c2' in the drawing below.'wt' is the weight transfer an...
When hard braking or downshifting  Size:       20kb.

Tip264: How dangerous is a quick squeeze
...ct.The red and blue lines are curved, however, to demonstrate that weight transfer reaches the tire contact patch in a non-linear fashion.Notice that at no time does the braking force generated by the front tire even approach the blue line - skidding is n...
during a quick-stop?  Size:       20kb.

Tip074: Weight Transfer
...he forces that try to slow you down when you apply your brakes are at ground level. That is, at the contact patches of your tires. On the other hand, the inertia of your bike works not at ground level, but directly through its center of gravity (CG.) Sinc...
What it is, why does it happen, and why should you care?  Size:       55kb.

Tip080: Swing Arms
...e counterclockwise. This, of course, is true even if the tire does rotate. That is, traction at the contact patch would push back against the tire with exactly the same force as the tire pushes against the road surface from acceleration, regardless of whe...
Your anti-squat linkage  Size:       25kb.

Tip094: Reading Gear Ratios
...ad center-line will be sloughing against the pavement while the tire along the outside edges of the contact patch (which are closer to the hub of the wheel) will determine distance traveled.)But from the information in your owner's manual you already have...
Determining speed potential  Size:       24kb.

Tip106: Center Of Gravity
...rear tire. If the CG was 55% of the distance along the wheelbase from the center of the front-wheel contact patch to the center of the contact patch of the rear wheel, then 55% of the total weight of the bike would be on the rear tire and only 45% on the ...
How to calculate where it is  Size:       38kb.

Tip163: Rake Angle And Steering
... ground. Please note how this defines ground trail. (The diagram exaggerates how far forward of the contact patch the steering axis point is for clarity.)When you turn the handlebar you are attempting to turn the tire about the steering axis at ground lev...
Trail Causes Self-correction  Size:       18kb.

Tip180: Weight And Traction
...aused by the wind drag. Downforce acts as a torque. That is, all forward pointing forces are at the contact patch and wind drag is through the Center of Wind Resistance so that, like weight transfer caused by acceleration, we know how much weight is added...
Management  Size:       30kb.

Tip187: Trail
... ground that is directly below the pivot of your steering stem, B is the center of the front tire's contact patch (which is what is actually touching the ground), C is the place on the ground pointed to by your steering stem axis and C' is the place on th...
The righting effect  Size:       25kb.

Tip188: Motorcycle Dynamics
...ut 33 inches with the rider.Without the rider the CG is closer to midway between the front and rear contact patches than with the rider. We will assume a motorcycle that has a wheelbase (WB) of 66 inches, and the length of the front weight bias (F) is abo...
Like physics, it's a balancing act  Size:       32kb.

Tip207: Weight and Mass
...n before the wheelbase shortened, the combined bike/rider CG would be directly above the front tire contact patch which it obviously is not.)So lets look at what actually happens when a rider stands on the pegs.The top graphic shows where the three CGs ar...
They are NOT the same thing!  Size:       22kb.

Tip142: Standing On The Pegs
... was at a dead stop and you were sitting in the saddle all the weight would be distributed onto the contact patches of your tires. That is, if the total weight of the bike (including you) was 1,000 pounds, there would be about 600 pounds on the rear tire ...
Does NOT lower the Center of Gravity of the bike  Size:       18kb.

 

             
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