Draft:Braking a motorcycle

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Suggested Emergency straightline Braking sequence when upright

Shut the throttle, apply the rear brake, sit up and lean back, all at the same time.

Reach forward and squeeze - do not snatch - the front brake with increasing pressure.

If either wheel locks, release that brake immediately and reapply with less pressure.

If the rear wheel lifts off the ground, release some front brake pressure to stop the bike tipping forward.

Disengage the clutch as you come to a halt

When banked in a corner, just carefully apply the rear brake.

(The rear brake is first, simply because your foot should be already on it).

Research has shown emergency braking competence is not related to rider experience. If riders are not taught properly, many will never be able brake properly, putting them at high risk.

These recommendations is based on standard racing practise, which minimises braking distances, and the theory (Cossalter).

Be Prepared

You should consider rolling off the throttle and covering the front brake in response to hazards, which will reduce your reaction time and braking distance significantly. This could save circa 0.5 seconds in front brake reaction time in an emergency, and makes locking the front wheel less likely as the rider starts with two fingers near the pivot joined after by two more fingers further away with more leverage.

Consider lightly touching the rear brake if there is another road users close behind. Watch the front wheel of cars at junctions for the first sign of them pulling out in front of you.

You can ride with two fingers (index and middle) almost permanently on the front brake lever, so you can apply it immediately. However, dependent on the design, it can make it difficult to fully shut the throttle, but as long as the clutch is pulled in smartly this doesn't effect braking, but could leave the engine racing. This potentially significantly shortens braking distances as the front brake is applied almost immediately. (Not for automatics without a clutch). However, if you haven't practised, it could make it more likely for the front brake to be snatched, balanced against stopping far more quickly.

Use a Phone App

You can use a free phone App such as iAccel Lite to test your braking ability. It shows initial speed, distance to stop and average braking g force, which should be 0.67g minimum to meets Highway Code braking distances. The theoretical limit is 1g after which most bikes will start to tip up. The best riders can stop in 2/3rds of the published distances.

Practise, Practice, Practise

If your bike doesn't have ABS do not practise alone due to the risk of falling.

It is vital that you practise emergency braking repeatedly to create the required 'muscle memory', so your response become automatic. This should avoid an uncontrolled panic reaction, which currently means circa 50% of riders in an emergency simply lock the front wheel and fall. Even with ABS, some riders can also simply fail to apply the brakes firmly enough, usually due to previous or current experience on bicycles.

If the ABS activates, the rider has braked too hard or usually initially too harshly. There is no evidence that ABS actually minimises braking distances, although it is a vital safety aid.

Gradually build up, braking harder as your confidence grows, always ready to release the lever immediately if the front wheel locks. Once the forks have compressed, and the weight transfered, which probably takes around a second, you can usually squeeze the lever as hard as you can without the wheel locking.

In theory it takes 200 repetitions, after which the memory and reaction becomes permanent and automatic. This is easier to achieve safely and quickly on a track.

As most of the speed is lost at the end of braking, the difference between the best and worst rider as tested is the difference between stopping in time from 60 mph, or a 40 mph potentially fatal impact.

Most track riders and racers already have this built in, as it only takes a day's racing or a trackday for this to become embedded into the rider's behaviour.

Why this sequence?

It's important to brake as quickly and as hard as you can, to avoid collisions or minimise impact speeds.

The rear brake should be applied first - because you can - as the rider’s foot is usually positioned directly above the rear brake pedal, or can be slid forward and down in a single movement. The rear brake only provides around 40% of braking, but applying it not only starts the braking process immediately, but also starts the vital transfer of weight onto the front tyre to maximise the braking. This makes locking the front wheel less likely. It also squats the machine down, lowering the cente of mass which also helps.

On bikes with linked brakes, this also activates the front brake partially, giving you cira 70% of the available braking.

The front brake alone provides intially 60% of braking, which increases to up to 100% as the weight transfers forward. Applying the rear brake first means the bike is already slowing as the rider reaches for the front brake lever, which probably takes circa 0.5 seconds = 44 feet at 60 mph.

The rider should be prepared to immediately release the rear brake if the rear wheel locks, although this in not vital, unless the machine slews to the side. The situation differs with linked brakes and the style of machine, notably cruisers, where the rear brake is more effective, but the basic advice is the same for all types of motorcycles.

At the same time, the rider needs to sit up, release the throttle, extend their fingers, grasp the front brake lever, straighten their arms, and apply steadily increasing pressure to the front brake lever to transfer more weight forward as quickly as possible onto the front tyre without losing front wheel traction. This requires a high degree of skill and practise. 

Riders need to be prepared to immediately release and reapply if the front wheel locks, which is usually caused by snatching, and also release some front brake lever pressure if the rear wheel leaves the ground. This also requires skill and practise to recognise and respond to.

Wet Roads

Wet roads need even more care with the brakes applies initially more gently, but once the weight is transferred onto the front tyre it is unlikely to skid unless there is standing water.

Braking Mid Corner

Firstly, the advice, if you believe you may need to brake mid corner in response to a hazard, usually caused by too high an entry speed or a tightening corner, is to simply look around the corner where you want to go, rather than where you feel you might end up.

You should countersteer instinctively, but can also counteersteer deliberately with practise, pushing on the inside bar. The bike intially falls in the opposite direction to which the steering is turned, helped by the gyroscopic effects of the front wheel, after which the rider will instinctively turn the bars back to stop the machine falling further.

A modern machine with decent tyres and ground clearance (not cruisers), can be banked at circa 45 degrees or more on reasonable road tarmac. Many crashes have been caused locally, the Lincs police informed me, on corners when the rider could have got around easily had they had the confidence. If you're not confident leaning the bike, then get some on-track training where you can practise in relative safety.

Providing the bike is not banked at an extreme angle, there is a surpringly large amount of grip available for braking (or accelerating) when the bike is banked, which is the light green area shown in the diagram below. This is based on 'Mohr's Circle' theory of grip.

Braking mid corner using the rear brake lightly should be practised with care, for use in an emergency. This increases the ability for the bike to turn as weight is transferred onto the front tyre which is doing the steering, the bike slows, squats and pitches slightly forward, sharpening the steering angle marginally, and the rear tyre is more likely to slip sideways, which is an old race bike trick for quicker cornering. This is like 'oversteer' in a car.

Worse case the rear loses traction and the rider may fall, but it's usually a 'low side', unless the rider releases the brake fully after a wide skid, when a 'high side' is possible. But overall the outcome is probably better as the machine will impact first, then the rider, rather than the rider being followed and struck by the machine.

The other alternative of a direct head-on collision with an oncoming vehicle or stationary hazard is likely to lead with a worse outcome.

Riders can also pick the bike up and brake, then turn again, if there is sufficient room and road width, but again tends to be a 'last resort'. This is usually a panic response and results from the machine being steered more tightly into the corner, which has the opposite effect from countersteering.

Riders can also apply the front brake lightly mid corner in an emergency, as it is potentially more effective than the rear, as most machines are designed with a slight front wheel weight bias. However it affects the steering, straightening it, and potentially 'sits the bike up' if not corrected, and so is more risky. Using the front brake in corners needs very careful training and practice, so is probably best left to professional trainers on a race track, with training and advice to road riders restricted to just looking where you want to go, avoiding 'target fixation', and countersteering and applying the rear brake mid corner in an emergency.

Trail Braking

Additional training in ‘trail braking’ into corners in an emergency could be of considerable benefit to riders, which we cover at The School, although it's an advanced riding 'failure to plan ahead'.

Racers consistently trail the front brake into many corners, using the light green area of grip shown in the diagram above. They gradually release the front brake pressure as their lean angle increases, with the brake being finally released sometimes just as the throttle is opened on corner exit.

This leaves virtually no safety margin, so is totally unsuitable for road riders to use as a routine, but is a useful tool to have in an emergency, allowing the rider to both brake hard and turn at the same time. This is particularly useful when a rider has misjudged their entry speed to a corner.

The difference between carrying the front brake into a corner, and applying the front brake mid corner, needs to be completely understood. When you enter the corner with the front brake applied, the extra weight is already transferred onto the front tyre, so it already has the ability to produce significantly more grip.

Re-applying the front brake after you have started to turn, leaves the rider with initially only circa 50% of the weight on the front tyre, which is also doing the steering, making a skid and fall far more likely without great care and very careful application of the front brake.

Again, if in any doubt, it is recommended road riders should just use the rear brake when banked.

Alw