Now, before we get started, I’d like talk about general stability on a scooter.
It is always worth bearing this in mind: A scooter is at its most stable when travelling at a constant speed in a straight line.
Why is that important to remember? Well, it’s because anything that causes us to deviate from that ideal condition is going to rob us of some stability. It is something we obviously can’t avoid, but it is worth keeping in mind so that as we are riding, we are continuously trying to keep the machine as near to that ideal as possible.
So, on to the brakes:
On most modern scooters, the brakes are laid out such that the rear brake is operated by the left lever, and the front brake is operated by the right lever. The exception to this is on vintage scooters, or any scooter that has manual transmission – where the rear brake is operated by a foot pedal on the right of the running boards.
How much braking should be done by each brake?
The optimum ratio in the dry is: 70% front, 30% rear.
The reason for this is that, as you apply brakes, most of the weight of the scooter and rider will be transferred onto the front wheel. For a given material, traction is a function of how much weight is applied to the surfaces (and surprisingly nothing to do with size of contact patch). This added weight on the front wheel will increase traction.
Conversely, weight will be taken off the rear wheel as we brake. This will make the rear wheel more prone to locking up. When the rear wheel is locked up, most of the traction will be lost, and the rear of the machine will want to “overtake” the front.
Take it from me, keeping the rear wheel at the rear is a very satisfactory state of affairs!
Does this braking ratio alter when it’s wet?
Yes, it does. When the roads are wet, this ratio should shift to 50/50.
Application of Braking
“A scooter is at its most stable when travelling at a constant speed in a straight line.”
How you apply the brakes is crucial to your safety. If pressed to come up with one word that describes the very best way to keep safe control of your machine at all times, it would be: “smooth”.
Everything we do on a scooter should be done smoothly and progressively. That includes braking, accelerating, turning, shifting gears (if riding a manual). There is no more sure way to upset your scooter than giving it sudden, erratic input. This smoothness becomes even more crucial in wet conditions.
Let me talk now about how this smoothness applies to braking.
It is necessary that all brakes have slack in them. You can feel this on your scooter as the free-play that can be felt when you first squeeze the lever. When braking – even in an emergency situation , it is important to first take up this slack – sometimes called “setting up” the brakes, before we start to progressively apply more braking pressure.
This will help us to avoid locking up the wheels. It also allows time for the suspension to do its job – and the suspension has a very important job to do in keeping your wheels on the ground.
Further, the front brake should be applied momentarily before the rear.
So, with all this in mind, let me outline the sequence of events which should take place – in order – when braking. Of course, this all happens hopefully in a fraction of a second:
- Front brake is “set up” by taking up the slack.
- Actual braking power starts to get applied to the front brake.
- Rear brake is “set up” by taking up the slack.
- Actual braking power starts to get applied to the rear brake.
You will remember me talking earlier about a scooter being at its most stable when travelling at a constant speed in a straight line. We can see that the very act of braking is taking us away from that ideal.
With that in mind, it would be prudent to avoid compounding things that take away from that ideal.
One sure way to compound this is to be braking while cornering. This really should be avoided at all costs.
A tyre has a finite amount of traction available to it. You can see in the image to the left that much of that traction is being used to turn the scooter.
If we exceed that available traction (say, by braking), the tyre will give way – often with disastrous results.
When we are braking in an upright position while going in a straight line, virtually all of that traction is available for our braking. When we are turning, a large percentage of that traction is being used for the actual turn. You can see that asking for more traction for braking purposes could easily cause the traction limit to be exceeded.
For this reason, braking is to be avoided while turning the scooter.
In this situation, keep your eyes on where you want to go. Do not be tempted to look nervously at where you may be heading. I have seen many riders fixate on their potential landing spot when they get into trouble, and, sure enough, that’s exactly where they go!
What should I do if a have a wheel lock up?
Firstly, don’t panic! Easier said than done, right?
It is worth remembering that if a wheel locks up, it is not a forgone conclusion that you have a date with the asphalt. It is just a very nicely worded invitation! You can avoid it if you don’t panic, and take preventative measures in a calm, smooth way.
If a wheel locks up, let go of that brake, then smoothly and progressively re-apply it. If it locks up again, rinse and repeat. Keep calm, and there is a very good chance you will recover.
About ABS brakes
ABS, which stands for Anti-Lock Braking System, was previously the domain of higher end motorcycles, but they are starting to appear more and more in the scooter world.
Personally, I am a big, big, fan. ABS works by continually monitoring the relative speed of the wheels. If the system detects an out-of-the-ordinary speed differential between the wheels, it starts to do precisely what I outlined above for dealing with a lock-up situation.
The difference is that the computer can modulate the braking far faster than we possibly could. It can also detect a lock-up situation well before we can, and will often start to modulate the braking even before a lock-up has occurred.
If a scooter you are considering buying has this facility, I would highly recommend it.
There is, however, one important point about scooters equipped with ABS brakes:
Just as it is important to actively practise braking – and emergency braking – on your machine, you should also practise braking if your machine is fitted with ABS.
Studies have shown that in a huge number of motorcycle crashes, it was found that the rider didn’t brake as much as they could/should have because they were afraid of locking up the wheels..
It is important that, if you have ABS brakes, you train yourself to brake to the fullest in an emergency situation, and let the ABS do its job.
[Update: One of our readers, Bob, brought up a very good point about “ponderous” brakes on some scooters, and how this may affect the regular 70/30 rule. Please take a look at the comments for this post.]
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