CORNERNING – INTRODUCTION
As any good armchair motorcyclist will tell you, “Harley-Davidson don’t go round corners”. They probably read it in the motorcycle press, so it must be true.
Roundabouts can be a good place to practice your cornering skills.
Here the road surface is in good condition, so Derek can safely use all of the SuperGlide’s ground clearance.
In reality, the cornering performance of a Harley-Davidson is normally only limited by their available ground clearance, which is quite low in many cases. But, to get in and out of the turns quickly, you will need to master the following skills:
This is the name given to the technique whereby you start a turn by trying to turn the handlebars “the wrong way”. So, to begin a left turn you push on the left handlebar or pull back on the right handlebar, until the bike is leaning over the right amount for the turn. For a right turn, you do the exact opposite, so you push on the right bar or pull on the left.
This is the only steering technique that really works with a bike as heavy as a Harley-Davidson. Also, because Harley-Davidson are big heavy bikes with slow steering, you need to apply more effort to countersteer them than you would need for a lesser motorcycle.
Note that you only need to steer with one arm at any time. Keeping the other arm relaxed can help to avoid panic reactions where you tense up in both arms. Under the latter conditions it is easy to end up by going straight on and thus failing to get around the turn.
You should aim to do any required braking and gear changing before you enter the turn. Then you need to drive the bike through the turn under power, not on a closed throttle. You should apply enough throttle for you to be able to feel the back wheel driving you through the corner.
If you use the front brake while cornering, you make it harder to steer the bike and you also increase the risk of a front wheel skid. If necessary, use the rear brake, e.g. for speed control on downhill curves or to help stabilize the bike during low speed U-turns. (I find that the latter technique helps to remove the temptation to “paddle” round and helps to produce tight “feet up” turns.)
You may also find that low speed turns become easier if you lean the bike over more while keeping your body vertical. This trick allows you to make better use of the tire profile to help turn the motorcycle.
CORNERING BY NUMBERS
Most cornering manoeuvres can be broken down into four main stages, as described below.
1 – The Approach.
Look ahead at where the road starts to turn and:
– using your skill and judgement, select your entry (peel off) point, where you will start to turn the motorcycle
– choose an appropriate entry speed and gear for the turn
– set your road position for the turn entry. Try to position yourself for a good view around the turn, but avoid poor road surfaces if necessary.
– look around the turn to see what you can see of the road ahead.
2 – The Entry.
When you reach your planned entry point (and not before), countersteer the bike into the turn. When the bike has leaned over enough, you should be able to revert to your normal relaxed grip on the handlebars.
3 – Drive Round the Corner.
For a constant radius turn, maintain a steady speed and lean angle until you can see the exit of the turn. Your speed should be chosen so that you can always stop safely in the distance that you can see to be clear. The point from where you begin to exit the turn is known as the apex of the turn.
4 – The Exit.
After reaching the apex, you can begin to steer the bike out of the turn. As you reduce the lean angle, you can begin to accelerate out of the turn. Alternatively, if you’re in the middle of a series of bends, you will want to start setting the bike up to enter the next bend.
With the SuperGlide positioned for a good view around the corner, safe and rapid progress can be made.
CORNERING – THEORY
This section considers the topic of cornering from a more technical viewpoint. This should be of interest for anyone wanting a better understanding of the processes involved when riding a motorcycle around corners.
In a corner, a motorcycle is constantly changing its direction. From a physics viewpoint, this means that it is accelerating, even if its speed is constant. Thus a cornering force needs to be supplied to produce the acceleration.
For a constant speed turn, the cornering force will need to act radially towards the center of the curve. This causes the bike to continually change direction without altering its speed. In practice, we already know how to supply this force. It is generated by leaning the bike into the turn.
Leaning the bike overloads the suspension by forcing it to work at an angle. The total suspension force then has vertical and horizontal components, where the vertical component is always just enough to support the weight of the bike. The horizontal component provides the cornering force.
Leaning the bike over generates the forces needed to make the bike turn the corner.
Increasing the lean angle increases the horizontal force. So the bike turns more rapidly. At the road surface, however, the sideways grip of the tires must be good enough to support the cornering force. If it isn’t, the bike will skid.
To help the tires to grip, it is important not to overload them with braking or acceleration forces while cornering. A front wheel skid will cause the motorcycle to run wide in the turn, often with disastrous results. On the other hand, a mild rear wheel skid will cause the back end of the motorcycle to step out, increasing the rate of the turn. This makes it much easier to safely control rear wheel skids.
Thus it is best to avoid front wheel skids while cornering. The normal way to do this is to not use the front brake and to keep the throttle open enough so that the bike is either gently accelerating, or at the least just maintaining a constant speed. Then if any wheel skids, it will be the back, which can actually help the process of cornering.
This should explain why the best way to tackle corners is to crack the throttle open once the bike has been leant into the turn. If you do this, you can relax your grip on the handlebars and drive through the turn “on the back wheel”. It is also good practice to maintain a steady throttle opening as you go around the corner. This helps the already overloaded suspension to do its best to cope with any bumps that may be encountered on the road surface.
ACKNOWLEDGEMENTS AND DISCLAIMER
The author would like to thank John Davies, who is a professional instructor (and HDRCGB member), for his help with this article. Not only did John check over the draft text, but he also helped out with the photography. Thanks are also due to Motex of Worcester for the loan of their SuperGlide for the photo session.
Whilst every effort has been made to ensure the accuracy of this text, neither the author nor the HDRCGB will accept any liability arising from the use or misuse of this material.
This version dated 21 May 2000 was published in ‘HarleyQuin’, The magazine of The Harley-Davidson Riders Club of Great Britain, and is published on the web for the benefit of riders worldwide.Content Copyright © 2000 Derek Putley, – Web Layout Copyright © 2000 – 2005 Mike Caddick- [email protected] 9 October 2000 , updated 11 May 2005