Scooter News Full Stop How to make the most of your scooter’s brakes.
Words by PETE CALLAGHAN, photography by PETE CALLAGHAN & SANDY SYMEONIDES It may be an old racer’s truism that you don’t need brakes because they only slow you down, but it’s not true. Brakes are very useful, and not just for stopping. They offer much more than that for the scooter rider prepared to go the extra step.
Unless you own a geared scooter, you’ll have front and rear brakes, operated by levers on the left and right-hand ’bars. Just like on a pushbike, the left hand operates the rear brake, while the right hand works the front. Some scooters have linked braking systems, where either or both levers operates either or both brakes to varying degrees. These tend to work very well, but what follows will be less applicable to these riders, since often the scooter will be doing the job for them anyway. Both brakes will stop you, but they work in slightly different ways, thanks to a little something I like to call the Laws of Physics.
Hit the front brakes hard and the rest of the scooter with you on it will try to rotate around the front tyre’s contact patch. At the very least this will compress the front suspension; at the worst it will lift the back wheel off the ground. All very spectacular when it is intentional, but terror-inducing if it happens when you’re not expecting it. It’s also very unlikely to happen with most scooters, thanks to the next part...
Hit the back brake hard and you’ll either come to a stop, or lock up the rear wheel, in which case you’ll also come to a stop, but rather later than you may have wanted to. The difference between using the front and rear brakes has to do with the weight distribution of a scooter. With all that engine, transmission and fuel at the back end, and only the front wheel and handlebars at the front, the weight is far from evenly distributed. The weight at the back is why you’re unlikely to lift the back wheel off the ground under heavy braking, even if it is what the physical forces are trying to do. It’s also why application of both brakes is recommended if you want to come to the quickest possible stop.
You can’t, however, just grab a handful and, again, that’s because of the weight transfer. Grab hard on the front brake and you may well find yourself locking the wheel and falling over. That is to be avoided. What happens is that when you grab the front brake, the sudden transfer of weight runs through the front suspension, compressing it completely. That means the front tyre, already working as hard as it can to cope with the inertia of the scooter, also has to deal with changes in road surface, like bumps, etc, since the suspension is completely locked. It does this by bouncing off the road if the bump is severe enough. The brakes stop the wheel instantly since it is no longer in contact with the road and when it comes back down it has stopped and can’t rotate. It follows the path of least resistance, which is sideways, and down you go. But there’s a cure.
If you squeeze the front brake gently, easing it on, the suspension has time to react to the sudden weight transfer and recover. Once it has – and this takes a fraction of a second – you can then squeeze much harder on the brake lever. In fact, you can go way beyond the pressure you would have used to lock up the front tyre if you just grabbed it. There’s another beneficial side effect to this method. It allows the front tyre to take some of the weight transfer, flattening out and offering a larger contact patch for braking.
The good news is that it is easy to practice. Try walking alongside your scooter and grabbing the front brake. You’ll feel the instant front-end dive. Now repeat the exercise, but squeeze the front brake on steadily. See? Much better! Get used to using the brake like this in day to day riding and work up to braking harder when you feel comfortable with it. You’ll be amazed how quickly you can stop and, do it enough, and it’ll be the automatic response when that car driver doesn’t see you.
Ordinarily on a motorcycle, the front brake does pretty much 80 per cent of braking (and up to 100 on a racetrack) , with the back used for that little bit more, or for steadying the bike. Both brakes applied correctly lead to the shortest possible stopping distance, but not too many riders have the capacity to concentrate on both their hand and foot and looking ahead to see what’s in the way at the same time.
On a scooter, however, the rearwards weight bias means the rear brake assumes a greater role in slowing and stopping a scooter. It doesn’t require as much fi nesse as the front brake because locking up the back end of a scooter is not so serious as losing the front. You’re likely to make a lot of noise and maybe scare yourself, but not to crash.
The way I use the brakes is in tandem. I generally start with the front brake, to set up the suspension and begin the braking process before easing on the rear if I need more. The delay between the application of front and rear brake levers need notbe huge, maybe half a second once you get used to it. It may work for you to apply the rear first – there will still be some weight transfer to the front, though not as much as if the front brake had been applied – and then the front.
Rear Wheel Steering
Not, not the fast and the furious, but another benefit of the Laws of Physics. Judicious application of the rear brake can help you get around corners. Assuming you are braking into a corner, as you stop braking and accelerate through the bend, the weight transfer that was at the front reverses and headstowards the back. This can extend the front suspension, increasing the effective steering angle and making the scooter want to run wide. Now it may not be immediately noticeable, but running wide in a left-hand corner is asking for trouble. A light application of the rear brake mid-corner balances out the weight transfer and keeps the front suspension in check, tightening your line and stopping you running wide. It also works if you are running wide and want to correct it. When braking for a corner, I use front brake, then the rear brake as well to slow for the corner before easing off the front brake and leaving the rear brake trailing until I’m at the exit of the corner. Hard on pads, but safer for me.
What about the front? You can use the front brake to steer, but it’s more complicated and harder to do. If you are leaning over, applying the front brake will make the scooter want to stand up straight. The effect can work very well on motorcycles at a racetrack where you have to change direction as quickly as possible but, because the reason it works is to do with rotational mass, speed and inertia, the smaller the mass and diameter of the front wheel, the less pronounced the effect is at scooter pace. It still works, but is really only useful if you have to get from full lean to upright quickly so you can get the brakes on hard. Practise at your peril: no amount of wishing will save you if you grab a big handful of front brake at full lean.
Them’s The Brakes
Scooter brakes come in two forms: disc and drum. Disc brakes operate with a metal disc attached to the front wheel being clamped by brake pads held in a caliper. They are usually operated by hydraulic pressure. Drum brakes take the form of a circular casting in the wheel, inside which sits a backing plate attached to the frame and holding two curved arms with brake pad material bonded to them. This system is almost universally cable-operated, the cable acting on an arm that turns a cam in the assembly that forces the arms’ braking material against the interior of the wheel hub. There are a variety of drum brakes based upon how many brake shoes and cams the system uses, but the most common in scooters is the single leading shoe brake, where there are two shoes (or brake pads) – one leading and one trailing – and one cam.
In absolute terms, disc brakes are more efficient, partly because they cool down more rapidly after use, spinning in the airstream as they do, but a well set-up drum brake is pretty efficient. It also works better in the wet, since there is no lag while the water on the disc is evaporated by the heat from the pads acting on the discs.
Correct set-up is the key. Disc brakes are self-adjusting, only needing periodic fl uid replacement. The fluid is hygroscopic, meaning it absorbs moisture over time and that leads to a loss of efficiency, but the system is closed and regular bleeding and/or replacement fl uid at servicing is all that’s needed.
Drums, on the other hand, are generally operated by a brake cable and both cable stretch and pad wear will lower the efficiency. Fortunately, there is a simple solution. If you look at the rear brake drum, you will see a rod with a threaded end running through an arm, with a nut on the end. Tightening the nut removes slack from the system. It’s worth checking the freeplay and adjusting it when there is too much slop.
The best way to do this is to put the scooter on its centrestand and tighten the nut until the brake just binds with the wheel. When you spin the wheel you’ll feel when the pads contact the drum. Then back off the nut a turn or so until the wheel turns freely. Make sure the pads don’t drag or the heat may cause swelling and your scooter will lock up its rear wheel without any pressure on the brake lever. If you’re in doubt, get the brakes adjusted by a reputable mechanic.
Being able to stop is an important part of being able to enjoy the ride.
As published in TW SCOOTER MAGAZINE - 26/04/2007
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