Senin, 10 April 2017

Dark Art of Suspension Part 1


In the 60s and 70s, most bikes used a simple damper rod in the forks, with a basic piston moving through oil to control the return (rebound) of the front-end. As bikes and tyres improved, more precision was needed. Enter cartridge forks. These give separate control of the damping as the fork compresses and rebounds, by moving oil within a chamber (the cartridge). A piston on the end of the sprung fork rod displaces oil through a valve in the base of the cartridge under compression. On its return (rebound), the oil is governed by a valve built into the fork rod’s piston.

During slow-speed damping (gentle movement of the bike’s suspension), a needle restricts the flow of oil through a hole in the centre of these valves, just like a pilot jet in a carburettor. In high-speed damping (over harsher bumps), a sprung stack of shims are pushed out of the way and the oil flows through carefully designed ports in the perimeter of the same valve. The spring and the compression damping both work to support your bike – reduce one, and you can balance it with an increase to the other, but then you have to consider the rebound damping that works against the spring when the suspension return

Your shock absorber is generally connected to the swingarm through a linkage (except on twin-shock bikes like the XJR) – which translates the travel of your rear wheel to the movement of the shock by a certain ratio: sometimes by as much as 3:1. There are also rising-rate and linear linkages to consider: A rising-rate (or progressive) linkage moves the shock by a greater ratio as the swingarm rises further. On a smooth track, a progressive linkage helps the rear get firmer as the suspension is loaded, making it easier to get the back wheel to spin up, and drift controllably out of corners. At the Isle of Man TT, for instance, there are large bumps, and fast changes of direction, so linear suspension is best: If the rear shock ‘locks up’, that force has to go somewhere, so the weight is thrown to the front of the bike over bumps.

On road bikes, while a linear setup would generally be the best bet, you’ll tend to find progressive linkages. Relatively cheap shocks are used on most of our machines, so the linkage is helping the shock to support the motorcycle, especially where pillions and luggage have to be taken into consideration.


Setup



It can be very difficult to obtain that perfect suspension set-up. On a stock road motorcycle, built to a specific budget yet designed for a huge range of rider weights (with the option to carry a pillion and luggage) getting it spot-on for everyone is, understandably, a near impossible task. A bike manufacturer has a huge window when designing a standard road machine – from the physically smaller, lighter Asian market, to the often larger US owners. Will the rider be carrying luggage? What kind of road surface will they be on? A bike with too wide adjustment could, in the wrong hands, be set up to handle dangerously.


Due to the litigious times we live in, this could prove costly for manufacturers; hence an average is accommodated for. It’s this lack of real adjustability that contributes to many riders not believing they understand suspension – until you can actually feel what’s happening as you tweak it, it will always seem something of a dark art.

To be continued....


Source:
Fast Bike magazine May 2017
http://www.cycleworld.com
https://www.morebikes.co.uk


Twist the throttle and enjoy the ride

Minggu, 09 April 2017

I Love It: Yamaha TMAX 2017


WITH EVER-INCREASING traffic and a dwindling supply of city parking, scooters have become a logical and popular choice for commuters – all you have to do is look at CBD parking lots to see a plethora of them. The reason for this is that scooters are easy to handle, convenient and relaxing, not only for the new rider but also the experienced motorcyclist who wants a runabout for the city. 

Back in 2001 Yamaha released its first TMAX, a scooter that could be used to run down to the local shops, but which also offered performance more closely resembling a motorcycle. Basically it was Yamaha’s attempt to bridge the gap between its scooter and bike ranges. For your information the 2017 model is the sixth generation of the TMAX. The latest incarnation has received a raft of changes and Yamaha says that it benefits from better acceleration, agility and lower weight. It’s also got a more sporty design with LED lights a great finish

Powering the TMAX is a 530cc liquid-cooled, DOHC, four-stroke, in-line two-cylinder engine that produces 34.2kW at 6750rpmand an impressive (for a scooter) 52Nmat 5250rpm. Ready to roll, with its 15 litre tank full up, it weighs 216kg wet. It’s not exactly light, but swap the 6 and the 1 around, and you’ve got the wet weight of the C650GT, which means the 15 extra horsepower the BMW has over the Yamaha isn’t a big deal.



The TMAX range has also expanded; it’s now made up of three bikes: the standard TMAX, the SX and the DX. The SX is the sportier version, and comes in racier paintjobs, whilst also getting a ‘D-Mode’ selector that allows you to switch between rider modes T and S. It also gets My TMAX Connect, a smartphone interface through which you can interact with your bike, and track it if some thieving swine decides to steal it. The DX is intended as the luxury option, for those who want to use it for longer journeys. It too gets its own exclusive colours, and also benefits from cruise control, D-Mode adjustable power modes, an electronically adjustable windscreen, heated grips and rider seat, an adjustable rear shock, and the My TMAX Connect system. How about the standard TMAX? Strip the heated bits, adjustable screen and power modes from the DX and you’ve got the base model TMAX.

Along with the Euro4-related engine changes, all the new TMAXs have YCC-T ride by wire throttle and traction control, which works by controlling the ignition timing and fuel injection. The DX has two riding modes. Said modes, which Yamaha terms D-Mode technology, are: Sport (S) and Touring (T). Both deliver the same power, but T mode gives you a much softer throttle map. Switching between modes can be done while riding, with the press of a button.

Equipped with Cruise Control, the system operates above 50 km/h, and can be increased or decreased in 2km/h increments by a single push of a switch on the left handlebar, or by continuously holding down the switch. Riders can easily cancel the cruise control by braking or turning the throttle past the closed position, and a ‘resume’ button returns the system to its last used speed setting. 



For added convenience the TMAX DX model is equipped with an electronically adjustable windscreen that can be raised or lowered by 135mm using a switch on the left handlebar. The specially designed screen works in conjunction with the central air duct to reduce air pressure and turbulence acting upon the rider, creating a more relaxed and comfortable environment. On the TMAX and TMAX SX models the screen is manually adjustable by changing the screen adjustment bolts, and offers 55mm of vertical movement. 

There’s also a new aluminium chassis, a narrower carbon fibre drive belt, lighter tyres (saving 1kg) and a narrower rear wheel rim (now 4.5”). The underseat storage compartment has grown, and the dash gets a new TFT central unit sitting between the analogue tacho and speedo, while the TMAX is also now keyless, and prepped to connect with Dainese’s D-Air system.


Source:

Australian Motorcyle News magazine, vol. 66 2017
http://www.visordown.com
http://www.motorcyclenews.com
http://www.bikeonline.com.au



Twist the throttle and enjoy the ride


Senin, 03 April 2017

Hearing Protections: Earplugs



Biking may be good for the mind, but it’s not that great for the hearing. Bikes themselves are wonderfully noisy things, but interestingly it’s not the roar from loud exhausts that’s the main culprit in damaging bikers’ hearing, it’s wind noise – that is at speeds over 40mph anyway. The National Institute for Occupational Safety and Health (NIOSH), part of the Centers for Disease Control and Prevention (CDC), recommends that workers should not be exposed to sound levels above 85 decibels in an eight-hour work day, and notes that noise levels of 100 decibels become damaging to the ear after just 15 minutes of exposure. 

Testing done by researchers from the University of South Alabama and William Patterson University, using an acoustically engineered dummy head and microphones, found that at speeds above 40 kph (about 25 mph), wind noise surpassed any noise from the motorcycle. At the highest speed tested, 120 kph (about 74 mph), noise exceeded 100 decibels at all the frequencies they measured. Put those two facts together and you get this: If you ride your motorcycle at highway speeds for more than 15 minutes without ear protection, you're damaging your hearing. And who wants to ride for just 15 minutes?

If your hearing sounds muffled after you’ve been riding a bike, or if your ears ring, then you’re suffering temporary hearing damage – which, if repeated regularly, may become permanent hearing damage. The best protection against this is wearing earplugs under your helmet. Ear protection helps with concentration as the constant noise of wind blowing in your ears is tiring. Are earplugs legal? Consult your local authorities.

WHAT ARE THE OPTIONS?

There are three main types of earplugs favoured by bikers: disposable ones, multi-use generic plugs and custom-made moulded earplugs. Disposable earplugs are great for those who don’t use the bike so often and stick to lower speeds in city traffic. Generic multi-use earplugs are a step up from the foamies and can be very handy if they suit your ears. The top of the range protection is offered by custom-made earplugs. These are expensive compared to a pack of disposable ones, but for riders who get through several disposable earplugs every week, the cost over a few years may actually be lower than using disposable ones.

DISPOSABLE EARPLUGS


Generic disposable earplugs are cheap and readily available, which makes them handy. They are usually made from foam and come in a range of colours from the boring yellow to some rather psychedelic colour combinations.

Generic disposable earplugs are designed for single use, which means you need a new pair every time you’re exposed to noise. If you don’t change them often enough dirt will start to build up and their ability to expand/ contract reduces, so don’t be tempted to wear the same pair for long.

How well disposable earplugs work depends entirely on the fit, and as these are generic products the fit is not guaranteed. Most products reduce noise levels by around 30dB if they fit well, but the problem is that if you don’t get the fit, you don’t get the protection.

MULTI-USE GENERIC EARPLUGS


If you don’t like the idea of disposable foam earplugs, the next step is multi-use generic ones. These are usually made from a rubbery material that doesn’t have the same issues as foam in losing its shape, so they can be used multiple times without a problem.

These earplugs can also be cleaned, which is a real boon. Because of their rubbery texture and a specifically designed shape, these earplugs stay in the ear better than foam plugs. Some multi-use earplugs are designed to block the harmful wind noise but to let some noise in through precision noise filtration.

Just like the foam earplugs, these are generic products, so they have not been designed to fit an individual ear perfectly and the same issue with fit remains.

CUSTOM EARPLUGS


With custom earplugs the fit is perfect because the plugs are created by taking impressions of each ear. This creates a unique fit, so you can be sure that your hearing is protected while you’re out on the bike. It also adds to the comfort levels, as the plugs are exactly the shape you need them to be.

Most custom-made earplugs last for years even under heavy use, but because your ears never stop growing a new mould should be made every three years or so to ensure that the fit is still perfect.

Custom earplugs come in different guises: the basic ones are usually made from medical-grade silicone or a similar ‘squidgy’ material, and they are small, lightweight and fully cleanable. There are also ‘filtered’ options that let some non-harmful noise in. And if you want to plug into your music, communications systems or sat nav, there are options with built-in speakers.


Source:
Twist & Go magazine July-August 2016
https://www.revzilla.com
http://www.cycleworld.com


Twist the throttle and enjoy the ride


Minggu, 02 April 2017

Descent With Motorcycle


Its been a very long time since i wrote article about motorcycle. Motorcycle its one of part in my life. Recently motorcycle had a small amount of attention because i spend more time in bicycle. So i think its good if i start to dig anything about motorcycle again, specially about riding technique. Below, its an article about how you should descent on the trail with motorcycle. Some point you can use in biking too where the others can't. Lets read it will ya?

BE AWARE
If you’re not aware and paying attention as well as you should and head into a downhill with too much speed, it’s a tough situation to backpedal out of. You should try to ride at a speed that allows you to stop within your field of vision.

SPEED CHECK
Begin at the correct speed and you can control it; come into the hill too fast and you’ll be fighting a tough battle. Your speed should be kept at a pace where you can maintain it and you can stop if necessary.  Control the speed and the biggest challenge is complete.

BRACE YOURSELF
Ideally, you want to stand up and lean back to the point of being able to brace yourself so that it’s physically easier. If you don’t lean back you’ll have huge amounts of pressure on your hands and arms, so let the bike pivot underneath you and get your weight to the rear of the bike. Either way, make sure you keep your head up and vision forward to help with selecting the best line options on the way down.



SQUEEZE, DON’T GRAB
Be sure not to lock your rear wheel. If you feel it lock, release it to keep the rear wheel turning.  Keep all of your control inputs progressive; the front brake especially should be a squeeze, not a grab. You’ll need to modulate the amount of pressure applied to the brakes, so try and do it smoothly

SMART LINES
Look for lines on the descent that will offer good traction and won’t lead you into a situation. Avoid loose surfaces where you can and be willing to move around on the trail to find the best traction available.

IF IT’S NOT STEEP
If the hill isn’t too steep and you can see the bottom, it may be possible to allow the compression of the engine to control your speed for you. The engine brake works well and allows you to stay away from the brakes, which can be preferable for less-experienced riders. Try to use the engine brake: shift downward until you have the right speed without the throttle, or with a bit of throttle. In a turn, open the throttle a bit. When it is so steep that your speed is too high, even in the first gear, you will have to use the brake as well.


Source:
Dirt Action Magazine, May 2016
http://www.lazymotorbike.eu


Twist the throttle and enjoy the ride


Gear Selection: How Low You Should Go?



Which gear should you use to enter a corner? Ask an experienced rider and they’ll usually pause and give you a blank look – and there’s a reason for that: gear selection is something most experienced riders perform without thinking. But there is a process and it’s important to get it right. Why? Because in the correct gear, you can comfortably accelerate out of the corner. That means smoother, faster riding.


DOING IT WRONG

Fall!!

Enter a corner in a gear that’s too low and your revs will be too high. This will make the throttle overly sensitive when you re-open it. A ‘screaming’ engine is also distracting in a turn and will disguise a lot of the bike’s road feedback. Also, the copious amounts of power available to the rider on a lot of modern machinery often means that the rider will be reluctant to open the throttle for fear of the rush of power when the revs are high. In addition, a lack of useable revs left means the rider will probably have to change up as the bike leaves the corner, disrupting the motion of the bike through the bend. On the flipside, enter a corner in a gear that’s too high and the engine’s revs will be too low, causing a very sluggish response when you open the throttle to exit the corner. This usually means you’ll have to downshift to another gear – not ideal in the middle of a corner.


DOING IT RIGHT

Lean and happy

Use your brakes to reduce your bike’s speed as you approach a turn and change down. Release your clutch the same way as you release your brake – smoothly and progressively. Ideally, you should do this before you enter the turn. In the right gear, your engine will be in its low-to-mid rev range through the turn. The right gear is the one in which you ride through the corner easily, and which allows you to accelerate out of the corner. Basically, we want to select a cog that limits the need for gear-changing through the middle of the turn, which is when the bike will be leaning most – not the ideal time for sudden braking, accelerating or gear changes that unbalance the bike. The revs you need will depend on your bike. Never look at the tacho on either bike to decide what gear is best. Decide it based on the feedback the bike is giving you.


Source: 
Motorcycle Trader magazine issue 319 2017
http://www.lazymotorbike.eu
http://www.visordown.com


Twist the throttle and enjoy the ride