This article is aimed at advanced motorcycle riding in a controlled environment.
“I don’t have a good feeling with the front.“
How often do we hear the MotoGP aliens say this ?
But just what do they mean, how do we feel the front?
Over decades of coaching the biggest anxiety I still see from riders is with the front end.
Fear Of The Front Brake
Fear of front tyre slides.
Nothing typifies this more than trail braking, that is, using the front brake to reduce speed while the bike is leant over in a corner. Even with ABS its still important to understand how to brake efficiently and trail braking is a must have for both track and the road riders.
Why the road riders I hear you say, you should have your braking finished before entering the corner on the road?
Well this is true. But things don’t always go to plan on the road or there would be no accidents, right?
The key to riding a motorcycle well is to understand the available grip.
This has obvious benefits on the track for lap time, reducing risk and increasing fun but also on the street where a rider who has high skill is less likely to succumb to a survival reaction, a major cause of motorcycle accidents.
To ride well, some knowledge of motorcycle dynamics is useful.
At motoDNA we are fortunate that 2 of our riding coaches are not only former International Road Racers but also former MotoGP Engineers.
This unique knowledge gained from racing plus race engineering at the highest level, is included in the motoDNA program, helping our student’s master riding techniques sooner compared to traditional training techniques.
Nothing to do with trail braking, trail instead refers to motorcycle steering geometry and is primarily designed to assist motorcycle stability.
To understand how trail works its useful to first think about a shopping trolley wheel.
It’s always wiggling about – from left to right.
As you push the trolley forward, bumps and surface irregularities knock the wheel side ways, but the wheel always self aligns to try and go in the direction of travel.
Your motorcycle is basically the same concept, but with a rake angle.
The wheel is always self-centering as a torque is generated at the tyre contact patch keeping the wheel straight.
The force you feel when pushing on the inside handle bar to counter steer is largely due to trail, with the road pushing the tyre back to keep the wheels in line.
Cruisers generally have a large trail which offers more stability but at the cost of heavy and slow turning.
The Triumph Rocket’s trail is over 150mm.
Shorter trail found on sports bikes will provide quicker steering but at the cost of stability.
The Yamaha R1 is 100mm.
Trial is also directly linked to roll rate or how quickly the bike goes to lean.
You may notice when the road is wet or slippery the steering feels lighter.
This is due to the tyre slip at the contact patch on the low friction wet surface.
This is steering feedback, indicating how much grip is available and is the same feeling but at a higher level when its dry.
The bike is talking to the rider, telling us how much grip is available.
More on this later…
On the track, a racer will approach a turn and at their braking marker apply full braking force normally with the bike virtually upright.
As they turn in, they reduce brake pressure, easing off the brakes or trailing the brake as the bike lean angle increases until they get to the apex when they release the brake completely and apply the throttle.
The racers goal is to go from top speed on the straightaway to corner apex speed in the shortest possible time.
Only the front brake is used for trail braking as the rear brake contributes little braking power, has less feel and is normally reserved for mid corner fine adjustments or to stabilize the bike.
Sounds easy enough in theory, but proper execution is complicated because it comes down to feel.
Fast Riders Have Slow Hands
As Freddie Spencer said, “fast riders have slow hands”.
Wise words and worth remembering.
To comprehend the dynamics of trail braking, ignoring any aerodynamic effects, some understanding of tyres and grip is beneficial, with the amount of grip from the tyres depending on various factors.
The main contributor to grip is the weight or load on each tyre. The ratio of maximum grip and vertical load is called the co-efficient of friction, and this normally decreases relative to the vertical load.
As the brake is applied, torque is transferred through the wheel to the contact patch, which creates a horizontal force at the track surface. The road pushes back on the tyre and equally the tyre pushes forward on the track surface.
Thank Newton For Mechanical Grip
You can thank Newton for this mechanical grip, as for each force there is an equal and opposing force.
Also to consider, is the significant grip increase experienced as the front tyre contact patch pressure multiplies due to the load transfer when braking. This grip effect decreasing as the lean angle increases and the load transfers off the front to the rear.
As the brakes are applied and the weight shifts forward, the forks are also compressed. This compression of the forks alters the motorcycles steering geometry, reducing the rake and trail. This decreases stability but increases maneuverability in a fashion that makes the motorcycle lean and change direction at a higher roll rate.
The tyres temperature also increases from this weight transfer and subsequent tyre loading, with tyre temperature windows critical for optimum grip.
Track surface characteristics and other elements between the track and the tyre such as water or oil also play an important part in available grip.
Feel The Force
Now that we understand trail and trail braking the next step is to understand how to develop feel.
Front grip feel is about developing fine motor skills and dexterity with our hands.
By coordination of small muscle movements involving the synchronization of hands and fingers with the eyes, to give a light touch on the handlebars, enables the rider to react to what the bike is doing in real time.
So if we have a light touch on the bars, how do we hold on?
Body position is critical, supporting your upper body weight through you core, thus reducing pressure on your hands.
Too much weight on your hands and you will loose feel.
The rider must be mindful of not only how weight transfers around the bike when braking, cornering and accelerating, but also how our own body weight and pressure move from our hands to our bum and feet.
Also, make sure your arms are bent.
As you go to lean drop your inside elbow aiming for 90 degree to the steering stem axis.
Another important element for developing and building feel is consistency.
If you are not consistent it’s difficult to accurately evaluate what’s going on.
This is best achieved by practicing step-by-step drills in a controlled environment under expert instruction.
This takes practice and a good coach who understands the skill level of the rider and by how much to raise the challenge for each step.
At motoDNA we increase the riders challenge in 5% increments followed by practice until the skill becomes intuitive, before repeating to go to the next level.
Too much challenge and you will see mistakes and inconsistency creep in, delaying progress and reducing rider safety.
Doing over saying always wins, so get yourself on track and feel the force.