Fica a primeira review dos travões Shimano XT M785.

Estes travões foram beber a tecnologia da Shimano disponível nos XTR, colocando-a a um preço bastante mais convidativo ;)

Fica o artigo.

Shimano’s new XT M785 brakes are possibly the best brakes from Shimano that we’ve ever ridden. They combine almost all of the features of the M985 XTR Trail brakes — Servo-Wave lever design, calipers with oversized ceramic pistons, Ice Tech rotors and cooling-fin equipped brake pads — at a much more economical price and only slightly higher weight. Those needing to upgrade their brakes should definitely add these to their shortlist.

Ride performance

We tested the M785s with finned Ice Tech pads and a 180mm front /160mm rear rotor combination on a 140mm-travel trail bike. After a short break-in period, it became immediately apparent that these new XT brakes are something special.

Power is second to no other trail brake we’ve used, while modulation is also very good. The brakes’ high power requires a light touch, which takes a little bit of getting used to, but they’re not too grabby. Even on long, fast descents, braking requires only one finger. The system seems so good that those concerned with weight, or lighter riders, will be able to get away with a smaller front rotor, even on a trail bike.

The ice tech brake pads with cooling fins are said to cap brake temperature, which offers more consistent feel and better pad life:

The XT brake is available with or without cooling fins on its pads, but after riding with them, we’d say they’re worth the slight bit of extra weight

Our test system was equipped with all of Shimano’s heat management bells and whistles—Ice Tech cooling fin equipped rotors and alloy core rotors—which kept their feel smooth and very consistent. With other brakes we find ourselves constantly messing around with the freestroke or pad contact adjustments and the lever reach adjustments while riding—if they are tool-free—yet with the new XTs we set them and forgot about them because the feel stayed exactly as originally adjusted.

We were thoroughly impressed by shimano's xt brake; it offers xtr trail performance without the price and only a slight weight penalty:

The new brake features tool-free reach and tooled freestroke adjustments along with Shimano’s new ‘One-Way’ bleeding

The levers are easily adjustable for reach and fit a variety of hand sizes, while the tooled free stroke (pad contact) adjustment is more precise than on the previous XT M770 brake. Based on our initial testing, these brakes warrant BikeRadar’s highest five-star rating. However, we feel it’s prudent to reserve that award until we’ve spent more time on them.

Fit and finish

The new XT M785 lever mirrors the XTR Trail lever that Shimano introduced last year. The first change most will notice is the swap from a radial master cylinder to a barrel-type inline reservoir. This offers better oil flow and Shimano’s One-Way Bleed process, which is said to be quicker and more consistent than the old system. The lever is Ispec compatible, meaning that the clamshell-type handlebar clamp can also be used to mount your shifters.

The new xt brake serves to 'launch' shimano's first 6-bolt ice tech rotors:

The new XT brake serves to ‘launch’ Shimano’s first 6-bolt Ice Tech rotors

The increase in power over the M770 brake is down to three factors: the two-piece calliper with 22mm ceramic pistons, the Ice Tech cooling-fin pads and the three-layer (stainless steel-aluminum-stainless steel) braking surface found on the two-piece rotor. Unlike the original XTR Ice Tech rotor, the XT version will be available in IS six-bolt as well as Center Lock versions. Shimano offer two color options for the new brake: the pictured matte black anodized with chrome highlights or muted satin silver.

Even the weight is competitive, at a claimed 375g per wheel when equipped with a 160mm rotor and standard pads. While the US$209.99 package price ($159.99 per wheel for lever, caliper, line and pads, plus $49.99 per rotor, regardless of size) can’t be considered cheap, it’s good considering the performance the brake offers.

Manufacturers description

The Servo-Wave Deore XT hydraulic disc brakes continue to borrow from the features developed for XTR that provide huge leaps in braking and control. The new compact caliper with oversized 22mm ceramic pistons is combined with a lightweight lever for a brake that lighter yet packs 25% greater braking power when the ICE Technologies brake pads and rotor. The rotors have been proven to reduce temperatures of the rotor as much as 100% over a standard all steel rotor, and will be available in a 6-bolt pattern as well as the Shimano innovated Center Lock. Mechanics will appreciate the integration of the same one-way bleed that debuted on XTR last year.

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Já falamos aqui no BTTecos de mudanças, 9×3, 9×2, 10×2, 10×3, enfim, todas as inúmeras hipóteses que os fabricantes nos apresentam.

Fica um artigo interessante sobre o tema e que desvenda um pouco o que poderá ser a evolução … lá para 2013 estamos todos a trocar de bikes ;)

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Gears are the components that define the evolution of the mountain bike. Don’t believe us? Take a look back in history, to Marin County, California where it all began. The legendary Repack started as a downhill race for beach cruisers in 1976, and the riders used a truck to get them to the top. Later that year, over in Colorado, those same pioneers pushed their klunkers around the first Pearl Pass Tour to Aspen.

The breakthrough that turned klunkers into mountain bikes was bodging road bike derailleurs onto them, enabling the bikes to be pedalled up the hills too. In some ways, not a great deal has changed since – levers on the bars move some dangly bits on the frame. But right now, there’s a lot going on in the world of bike transmissions, with more options than ever before and even the odd challenge to the dominance of the derailleur. Join us as we sink out teeth into the world of gears…

Why use gears?

The ability of riders to put out maximum torque (crudely put: how hard you can push the pedals around) at low revs means that while multiple gear ratios are useful, they’re not essential. It’s not just modern-day singlespeed riders who demonstrate the truth of that, either. The Tour de France ran for 34 years before derailleurs were first used, although riders could turn their rear wheels around to use a different-sized sprocket on the other side.

However, if you’re a mere mortal, riding up big hills without gears means you either need strong legs and lungs, a high pain threshold, or a combination of the two. Once lots of gears became available, they were soon put into widespread use – no one’s winning races with one or two gears any more, unless it’s a race specifically for gear-deficient bikes. This is because gears allow you to make the most of your muscles.

You need a certain amount of power to move your bike – how much depends on how fast you want to go, what you and your bike weigh and the gradient you’re riding on. Power is a function of your torque and pedalling speed (or cadence) – to generate power you can either pedal slowly but push hard, or pedal quickly and push less hard. Thanks to the way your muscles work, you can maintain fast, easy pedalling for much longer than slow, hard pedalling.

A choice of gears enables you maintain a fairly constant cadence across a wide range of speeds and inclines. On a singlespeed, to go twice as fast, you need to pedal twice as fast, and it’s easy to run into muscle fatigue (or simple lack of strength) problems at one end of the speed range and the possibility of your legs flying off at the hips at the other.

Gear anatomy

Cassette: The stack of sprockets that acts as the bike’s gearbox. Small sprockets provide higher gears, and big ones result in lower gears. While 9-speed cassettes are the current standard, SRAM’s flagship XX delivers 10 and pretty much everything will be 10-speed for 2011.

Cassette:

Rear derailleur: Also known as a rear mech, this assemblage of links, pivots, jockey wheels and springs does two jobs. Firstly, it moves the chain between different cassette sprockets in response to the shifters. Secondly, it takes up slack chain as the chainring and sprocket sizes vary.

Rear derailleur:

Front derailleur: This is attached to the seat tube with a wraparound clamp or bolted directly to a mount on the frame. Also known as a front mech, its cage shunts the chain across the chainrings.

Front derailleur:

Chainrings: Chainrings alter the range offered by the rear sprockets, a bit like the transfer box in a Land Rover. The middle ring’s for singletrack andmellow climbs, the inner (or granny) ring is for the grunty stuff, and the outer ring’s for going fast. Three is the current standard, but twin-ring set-ups are becoming popular.

Chainrings:

Chain: The chain is pulled around by the chainrings and pulls the sprockets around to turn the wheel, thus converting your efforts into forward motion. It has to cope with high tension as well as being able to deflect sideways to change gear.

Chain:

Shifters: Your point of contact with the transmission. The shifters pull cables to move the derailleurs. Twin-lever triggers (one for up, one for down) are the most popular choice, such as Shimano’s Rapidfire, but you’ll also find twist shifters, such as Grip Shift, and integrated brake lever/shifters.

Gear shifter:

How derailleurs work

Derailleurs, also called mechs, have been with us for a long time. Early models of rear mech, which have long arms pivoting backwards from the chainstay, are hardly recognisable as derailleurs now. But by the late 1930s, the familiar parallelogram design mounted near the rear axle had arrived. One end of the parallelogram linkage is attached to the frame, the other to a cage with two jockey wheels in it.

The cage is sprung to allow it to take up chain slack, which results from using the same length chain on different chainring/sprocket combinations. The linkage moves the cage in and out, pushing the chain onto adjacent sprockets. The shifter cable pulls the derailleur one way, acting against a spring that pulls it back when the tension is released.

1950s campagnolo gran sport road bike rear mech:

This 1950’s Campagnolo ‘Gran Sport’ road bike rear mech shows how things have advanced!

Early derailleurs had the linkage moving horizontally, meaning that the distance between the upper jockey wheel and the sprocket got bigger as you shifted to smaller sprockets. That made for inconsistent shifting across the sprockets, but it took until 1964 for SunTour to realise that it would make more sense for the linkage to be tilted to allow the upper jockey to remain a more constant distance from the sprockets.

That simple development allowed SunTour to dominate bike transmission production for 20 years until its slant parallelogram patent ran out, at which point everyone else started using it, including previous also-rans Shimano.

Shifter ergonomics

Early shifters were simple levers with friction devices to keep them in place. Then indexing came along and the levers got distinct clicks, providing helpful feedback. Next, the simple lever evolved into a pair of thumb levers, or a twisting barrel on the bar. Then one of the levers became a finger trigger, until double thumb levers were reintroduced. Finally, the finger trigger could also be pressed with a thumb. Or the shifter was married to the brake lever and you moved it up and down to change gear.

Shimano slx gear shifter:

Dual lever gear shifters like this Shimano SLX unit are popular today

These days, the field of shifters has settled down somewhat. The underbar trigger is the dominant design, although integrated Dual Control brake levers and twist shifters still have niche appeal. Having settled on a shifter design, you’re left with some set-up options. Dual Control’s double-duty brake levers let you choose how far along the bar they’re set and at what angle, but that’s about it.

Twist shift users can opt for different length fixed grips, setting their hands closer together or further away from each other. Triggers can be set at different positions or angles relative to the brakes, and some models can be fitted inboard or outboard of the levers too. Test and see which set-up works best for you.

Twist shifters used to be big but they're a niche product now:

Twist shifters used to be big, but they’re a niche product now

Compatibility

Most bikes come with a mish-mash of components from different groupsets, but not all parts will work together. There’s no problem with chains or cassettes – all 9-speed cassettes have the same sprocket spacing, so you can drop an SRAM one into an otherwise Shimano set-up (or vice versa). You can also use 9-speed derailleurs with 8- or 7-speed cassettes as long as you’re using a shifter with the correct indexing set-up. The only real no-no is mixing SRAM and Shimano shifters and rear derailleurs. Shimano uses a 2:1 actuation ratio (two units of cable pull give one unit of derailleur movement), while SRAM uses 1:1, so they won’t work together. SRAM does sell Shimano-compatible versions of its trigger and twist shifters, though.

Planetary gears explained (Truvativ HammerSchmidt and hub gears)

Planetary gear systems are a way of packing gears into a small space, and so are rather handy for bicycles. A planetary gear comprises a ‘sun’ gear in the middle, a ‘ring’ gear around the outside and a number of equally sized ‘planet’ gears connecting the two. Depending which component is held still and which turns, the parts will move at different speeds.

In a Truvativ Hammerschmidt crank, the crank arm is attached to the smaller planet gears via what look like chainring bolts. The actual chainring is driven from the ring gear, while the central sun gear is attached to the frame and can’t rotate. In the low gear, the whole lot is locked up so the chainring and crank spin together. Unlocked, the chainring is driven round 1.6 times every time the crank rotates, providing the ‘overdrive’ gear.

Truvativ's hammerschmidt is an enclosed planetary system that provides two modes – normal and the 1:1.6 overdrive for trail mashing:

Truvativ’s HammerSchmidt is an enclosed planetary system that provides two modes – normal and the 1:1.6 overdrive for trail mashing

You can see the central ‘sun’ gear, the ‘ring’ and the four tiny ‘planets’ inside the hammerschmidt:

You can see the central ‘sun’ gear, the ‘ring’ and the four tiny ‘planets’

In a hub gear, the sprocket is attached to the sun gear and the ring gear is on the inside of the hub shell. To get more gear ratios, a whole bunch of different sun/planet combinations are mounted side by side, with spring-loaded clutches to engage different ones. The Rohloff Speedhub’s 14 gears are achieved with a couple of planetary gears giving seven ratio options, plus another planetary gear that multiplies up those seven to yield the full 14.

Rohloff's hub gear uses a planetary system to provide 14 distinct, evenly spaced gears:

Rohloff’s hub gear uses a planetary system to provide 14 distinct, evenly spaced gears

The rather confusing innards of a speedhub:

The rather confusing innards of a Speedhub

Range, steps and options

Your gear preference all depends on your strength, favoured cadence and how fast or steep you plan to ride. If you’re scaling mountain passes then descending the other side as fast as possible, you need as wide a range of gears as you can muster. But as there are only so many different gears you can have and the wider the range you want, the bigger the jump between one gear and the next will be.

Racers like close ratios so they can find just the right gear for maximum efficiency, and they’re willing to sacrifice range for it. But as bikes have sprouted ever larger numbers of gears, this tradeoff becomes less acute; if you’ve got more gears to cover the range, they’ll sit closer together. On a typical mountain bike, one gear is about 10 percent higher or lower than the next, and given the variability of terrain there’s not an awful lot of justification for going closer than that.

If your gears are too closely spaced, you end up having to shift several at a time in response to changes of incline in the trail. The conventional triple chainring setup leads to three overlapping ranges of gears and you’ll be able to find a couple of different chainring/sprocket combinations that deliver the same overall gear ratio.

The bigger the range of gears you want, the larger the difference between each gear becomes:

The bigger the range of gears you want, the larger the difference between each gear becomes

So while you may have 30 gears on paper, depending on your exact choice of chainrings and cassette, that might mean you only have 18 or so unique ratios. That’s the thinking behind Rohloff’s 14-speed hub – every gear is different, and they’re all equally spaced. The jumps between them are a little bigger than between adjacent cassette sprockets, though.

You may want to deliberately limit your gear options for various reasons. Twin-ring setups are popular with all-mountain riders doing without an outer chainring for added ground clearance and less chain flapping around. At the other other end of the spectrum, cross-country racers may opt to do without an inner ring for more reliable front shifting.

Trail riders are starting to experiment with 1×9 setups, using a middle-size chainring and wide-range cassette for a simple solution that offers most of the gears you’ll ever need. Or there’s the even simpler singlespeed option, which can be a simple, reliable and (on the right trails) rewarding setup.

Some riders choose to go singlespeed for the ultimate in simple reliability:

Some riders choose to go singlespeed for the ultimate in simple reliability

Setup comparisons

There are plenty of gearing options available off the shelf. The chart you’ll find below shows the gear ranges offered by five common setups. A gear ratio of one means one revolution of the wheel for every revolution of the cranks or direct drive. Anything below that is a very low gear. The left-hand end of each bar is the lowest gear, the right-hand end represents the highest.

All these ranges can be tweaked by choosing different parts. For the sake of comparison, we’ll say the 27-speed setup is the common 22/32/42T chainset and 11-32T cassette. Twin and bash is the all-mountain/freeride-friendly 22/36T double chainset with a bashguard instead of a big chainring and a 11-34T cassette. SRAM XX is a race-oriented 28/42T chainset and has a 11-36T 10-speed cassette. Finally, the Rohloff and Alfine hub gears can be used with a wide variety of chainrings and sprockets, and different ones will shift the bars left or right. The illustration here assumes a 40/18T for the Rohloff and a 32/18T for the Alfine.

Gear ranges comparison chart:

Mechanical efficiency

Measurements have been made of bicycle drivetrain efficiency and the results are quite impressive. In a clean lab, a bike transmission can be almost 99 percent efficient – just one percent of the power put in at the pedals fails to make it to the back wheel. That’s amazing for a mechanism that’s remained fundamentally unchanged for about 130 years.

You’re not likely to be getting 99 percent efficiency out in the real world, though, and some of the factors that affect efficiency aren’t immediately obvious. The main one turns out to be sprocket and chainring size, with bigger ones being significantly more efficient. For a given chainring size, you might see 99 percent efficiency with a 21-tooth sprocket but only 95 percent with an 11-tooth sprocket.

That’s quite a difference, suggesting that if you can achieve the same gear ratio using a bigger sprocket (42/21T instead of 32/16T, for example) then you’ll be pedalling more efficiently. Surprisingly, lab tests show there’s hardly any difference in measured efficiency if the chainring and sprocket are offset sideways, contradicting the common dictum that extreme crossover gears like big chainring/big sprocket should be avoided.

Lubricating the chain doesn’t seem to make much difference in the lab either. But there’s a world of difference between a clean lab with a simple run of chain between two sprockets and the grubby outdoors with derailleurs and worn parts. Extreme crossovers tend to be noisy, which is always a bad sign, and tend to stretch the chain. And as soon as there’s dirt, grit and water around, lubrication is clearly a good idea.

You’re not likely to be getting 99 percent efficiency out in the real world:

You’re not likely to be getting 99 percent efficiency out in the real world

What does the future hold?

Ten-speed cassettes are no longer the preserve of the rich or the sponsored. SRAM’s 2/3×10 X7 groupset is already available and the new 3×10 Shimano Deore is set to be released in June. We’re expecting 2011 to be something of a watershed year for hub gears, too. Shimano’s Alfine is getting a bump to 11-speed with a gear range equivalent to that of an 11-45 cassette. It can’t quite match Rohloff’s derailleur-rivalling range, but it’s likely to be far cheaper.

Then there are systems that have been bubbling away for years. Centrally mounted gearboxes have weight distribution and suspension benefits but add complexity. Toothed belt drives are low maintenance, clean and quiet but require high tension hub gears (or a single gear) and frames with gaps for fitting them. It seems likely that chain drives and derailleurs will dominate the mountain bike market for some time to come.

Gearbox bikes have been in development for several years now:

Gearbox bikes have been in development for several years now

However, the Achilles’ heel of current gears is that they use a mechanism that dangles off the bike waiting to be mashed by rocks Looking further ahead, a replacement must surely be the next big advance. Conventional hub gears are too heavy and inefficient for use outside of specialist applications, but continuously variable transmission (CVT) might be the answer.

CVT systems promise to free us from the constraints of choosing gears by giving us as many as we like across a range, with instant shifting. Current CVT systems are too heavy for performance use but there are some determined engineers out there working to fix that. Finally, Shimano’s electronic transmission for road bikes (Dura-Ace Di2) has proven hardy enough to stand the  almost off-road conditions of the Paris-Roubaix race. Will we see it on mountain bikes one day? We already have.

Shimano's dura-ace di2 road groupset offers electronic shifting:

Shimano’s Dura-Ace Di2 road groupset offers electronic shifting

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Para quem ainda não conhece, fica a dica!

Trata-se de um adaptador para iPhone que permite ler e registar os dados de todos os sensores ANT+ que tenhas na tua bicla!

Desta forma podes tirar partido dos sensores da Garmin em que já investiste e usares Apps como o Fisica, o Endomondo ou o Runkeeper pro para seguires os teus treinos e a tua evolução. Podes ainda partilhar no Facebook todo o esforço de preparação de forma simples e prática.

Conto escrever mais um pouco sobre estas aplicações em breve aqui no BTTecos.com.

Wahoo Fitness takes the Apple iPhone to another level as a high-end training tool, by making it work with the ANT+ wireless protocol. This means that with the small ‘dongle’ inserted, the phone can pick up data from almost all top-end cycling and fitness gadgets.

This includes the heart rate, cadence and speed sensors made for Garmin’s GPS bike computer range, PowerTap and SRM power meters, and Nike’s running sensors. To showcase the data you can collect, Wahoo Fitness have their own free app called Fisica Fitness, and we tested this on a 3G iPhone with both Wahoo’s own speed and cadence sensor and HR strap, and the same devices from Garmin.

It worked seamlessly with all of them, and a PowerTap hub, thus marrying up Garmin Edge-like data collection and display to a seemingly endless supply of third-party apps. The full bike pack, which includes the cadence/speed sensor, HR strap and a weatherproof sensor case with dongle, will soon be available for about £150.

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BTT feita de … tinta?!

On 2011-03-10, in Blog, by Tigas

Ora aqui está uma ideia inovadora … vamos ver se pode ser aplicada no BTT!

We’ve seen all sorts of objects printed from 3D printers, but the European Areospace and Defence group (EADS) has shown off the first bike made from nylon—which they’re saying could replace traditional steel and aluminium bikes due to the affordable method it’s created.

Drip by drop, each part of the bike is made from powder using the Additive Layer Manufacturing process of 3D printing, with the machine connected to a computer loaded with the CAD bike design.

Aluminium bikes are already pretty light, but EADS is saying their nylon Airbike is 65 per cent lighter. It’s also more eco-friendly to produce, and due to the nature of 3D printing, individual parts can be printed easily if damaged. I really like the look of it, but that saddle doesn’t look like it’d be much of a friend to my bum.

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BTT – Leão Pinto no Andalucia Bike Race

On 2011-03-02, in Blog, by Tigas

O campeão português Luis Leão Pinto (Por) e o espanhol Alejandro Diaz de la Peña (Esp) venceram hoje a 4ªetapa da Andalucia Bike Race, prova de BTT de 6 dias na qual participam alguns dos melhores betetistas do mundo.

Encontram-se neste momento em 4º lugar na geral.

Força para as próximas etapas. O BTTecos.com vai continuar a apoiar-vos.

Segue aqui os resultados em directo.

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Bicla com olhos!

On 2011-01-18, in Blog, by Tigas

Descobri mais uma invençaõ que serviria a alguns BTTecos.com que eu conheço ;)

Uma bicla com camaras e display para veres o que se passa atrás de ti … muito interessante …

This Bike Has Eyes In the Back of Its Treads

This Bike Has Eyes In the Back of Its TreadsThis gorgeous bike not only turns heads, it makes sure you don’t have to turn yours. Because hidden away in its seat-stays lurks a rear-view camera that continuously records what’s behind you.

Not only can you watch your tail with the Cervellum Hindsight in real-time via a 3.5-inch, handlebar-mounted LCD monitor, the camera also registers when there’s a crash, continuing to record for ten seconds. Anyone who’s ever been clipped in a hit and run now has access to hard evidence.

Now for some good news/bad news. The bad news is that the actual bike shown above is just a concept from Evan Solida’s Rael. But far outweighing that minor inconvenience is that the Cervellum Hindsight is an actual product! One that’s going to be on sale, well, sometime, hopefully, maybe. Price and date are still TBD. But a soon as it’s available, you can bet I’m gonna be sizing it up for my tandem bike collection.

Original aqui.

Pioneer = Ciclocomputador Android!

On 2011-01-17, in Blog, by Tigas

Imaginem o meu espanto com esta notícia … a Pioneer está a desenvolver um ciclocomputador… baseado em Android!

As possibilidades são imensas portanto, navegação, processamento avançado de sinais com informação online ao ciclista, correcção de pedalada, melhor doseamento de esforço…

E como suporta Ant+ não vamos ter de deitar fora todo o nosso investimento em sensores o que ainda melhora as coisas :)

Fiquem com a notícia e veja o video que vale a pena…

Pioneer engineers Android-powered cyclocomputer, might remind Landis to stop doping

Think Android has reached its limit when it comes to applications? Think again. Pioneer has conjured up a new cyclocomputer, and compared to the antediluvian rivals available on the market today, this one looks like a bona fide supercomputer. It’s designed for mounting on the bike’s handlebars, where riders can then see speed, cadence, heart rate, and power at a glance. The device is engineered to play nice with the ANT+ wireless specification, and it can also pull data from optional crank sensors that can be installed to monitor one’s pedaling force. Furthermore, it’s equipped with GPS, and we’re guessing it’s a prime candidate for running Google’s own My Tracks app. There’s no time table for release, but we’re guessing the International Cycling Union will have one out in no time… one that continuously tests riders for illicit substances, of course. Video’s after the break, if you’re down for more.

Origial aqui.
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Treino com Rolos! Combater a invernada…

On 2010-12-15, in Blog, by Tigas

Mais um artigo interessante que descobri na Net!

Especialmente nesta altura de inverno em que não apetece andar à chuva e estragar material…

Rollers are viewed with suspicion, incomprehension or downright fear by many riders – a dangerous liability only suitable for hardcore experienced riders. But once mastered, they can provide a valuable addition to the training armoury of any cyclist, regardless of experience.

Although essentially based on the same simple design that’s been used for years, modern rollers have evolved and are much more user-friendly than those of old. Improved bearings offer a smoother ride, and smaller drums are easier to get spinning and mean less distance to fall. Some roller sets now have parabolically shaped rollers which make it easier to stay on.

Roller rewards

There are two major benefits to rollers when compared with using a turbo trainer. The first is that riding on rollers is a fast-track method to improving your balance and bike handling skills. If you struggle on the road with basics such as holding a straight course when getting a bottle out of its cage, digging an energy bar out of your jersey pocket or putting on a waterproof on the go, then you could definitely benefit from the balance and core stability training that rollers deliver.

Edmund Burke, coach, former physiologist for the US cycling team and author of Serious Cycling, agrees. “It takes weeks to be able to ride on rollers and feel relaxed enough to lift your hands off the handlebars,” he says. “Once you get past the learning stages, the bike handling skills you obtain will make you a more confident and successful cyclist.”

The second is that the high cadence workouts typically performed on rollers are perfect for developing a super-smooth, even and efficient pedal stroke. Poetically described by the French as ‘souplesse pedalling’, it’s what pro riders spend most of the winter working on and what separates great riders from the merely good.

Dr Jamie Pringle, senior physiologist at the English Institute of Sport, sees this as a major benefit. “Pedalling style is a major component of fitness,” he says. “An efficient pedal stroke ensures that the delivery of force is economical. This, not engine size, is what differentiates a pro from an elite or first category rider. On a turbo you can get away with mindlessly mashing the pedals, on rollers you can’t.”

Key strokes

By concentrating on key aspects of the pedal stroke when roller riding you can go a long way towards minimising the dead spots at the top and bottom of the stroke, and improving efficiency. “Don’t think you have to pull up on the pedals,” says coach John Capelin, “but focus on scooping through at the bottom of the stroke and pushing over the top. Sort out your pedal stroke and you’ll save loads of energy.”

Another benefit is that you get a more interesting workout than on a turbo because you have something to concentrate on. The ease of setting up is also a bonus – you don’t have to bolt your bike on – and rollers are less stressful on your bike because it’s not fixed in position and subjected to unusual loads.

There are also disadvantages though. You’ll have to invest some time in learning to ride the rollers and, although some sets come with optional resistance fans or other methods for raising the training load, you won’t be able to get near the forces you can generate on a turbo.

For this reason, an ideal winter indoor training plan would include a combination of turbo and roller work. “Rollers don’t offer much resistance so use them for technique work, warming up and recovery spins,” says Capelin. “Use the turbo for higher level work.”

“Turbos and rollers both allow you 100 percent control of your effort and intensity,” says Pringle, “and, without having to worry about traffic and junctions, they’re ideal for finely controlled, constant power efforts such as intervals. Riding for two hours indoors, without stops or being able to freewheel, is equivalent to three hours on the road.”

But before you head permanently indoors for the winter, he offers the following warning: “No matter how close the turbo or rollers come to the feel of riding on the road, they’ll never replicate the exact demands of the sport and you’ll still need to get out and do the miles outdoors as well.”

Technique

1 Starting off: Put your bike in a low gear and have the rollers set up close to a solid object such as a wall or doorway. Make sure your wheels are in the middle of the rollers and, keeping one hand on the wall, begin pedalling at 60rpm. If you have a willing volunteer, an alternative is to have them hold your handlebar; you’ll be more balanced to start with and the learning process will be quicker.

2 Going straight: Look straight ahead. You don’t watch your front wheel on the road, so don’t on the rollers. Once you feel confident in your balance and you’re staying central, let go of the wall, build up your cadence and you’re off. After a few sessions you’ll gain confidence and develop more advanced skills.

3 Mind on the job: Concentrate on what you’re doing – no watching TV at an odd angle or turning around to see who’s just come into the room… To stop, you need to simply slow down gradually and, before you come to a complete halt, reach out for the wall.

Example sessions

1 Wake-up: Dr Jamie Pringle’s pre-breakfast session works well for anyone who can split their training into twice a day, which can be more beneficial than one longer session. It’s a great way to start the day and an excellent warm-up.

0-10 minutes: Start off spinning in an easy gear at 90-100rpm and, over 10 minutes, increase the gear incrementally.

10-15 minutes: Continue building cadence (100-110rpm) and progressively work through the gears so that by the 15-minute mark you’re riding at tempo effort. This pace will feel sustainable but will need concentration to keep it up and equates to around 80-90% of maximum HR.

15-20 minutes: Hold the tempo effort.

20-25 minutes: Put in three hard 20-second efforts with 90 seconds of easy spinning recovery.

2 Spin-ups: An ideal session for developing cadence and smooth pedalling. Also great as a warm-up before hitting the road or as a pre-turbo roller session.

0-5 minutes: In a medium gear (39×18), ride easily, building your cadence to 100rpm.

5-5:30 minutes: Staying in the same gear, ‘spin up’ to the maximum cadence you can manage without bouncing. Hold the cadence through to the end of the 30-second period. Concentrate on getting your lower legs and feet to relax.

5:30-20:30 minutes: Repeat the spin-up on every fifth minute (10, 15 and 20). Spin easily at 90-100rpm for each five-minute recovery.

3 Maxing out: A tough session that will take you to total failure.

0-5 minutes: Warm up, spinning at 90-100rpm in a medium gear (39×18).

5-10 minutes: Ride a cadence of 100rpm+ and a gear that allows you to ride at 60% of max heart rate.

10:00-10:30: In same gear, do 30-second all-out effort.

10:30-13:30: Recover: spin easily in medium gear.

13:30-18:30: Ride a cadence of 100rpm+ in a gear that makes you ride at 65-75% max HR.

18:30-19:00 In same gear do 30-second all-out effort.

19:00-23:00 Recover: spin easily in medium gear.

23:00-29:00 Ride a cadence of 100rpm+ in a gear that allows you to ride at more than 80% MHR.

29:00-29:30 In same gear do a 30-second all-out effort.

29:30-34:30 Recover: spin easily in medium gear.

34:30-END All-out in top gear for as long as you can.

Rolling, rolling, rolling

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Portuguesas triunfam na Claro Brasil Ride

On 2010-12-14, in Blog, by Tigas

A dupla de Loulé, Celina Carpinteiro e Ivonne Kraft  da Bionicon Loulé, venceu a primeira edição da Claro Brasil Ride, conseguindo vencer as seis etapas da prova!

De destacar que na última etapa chegaram ao sprint com as brasileiras Janildes Fernandes e Julyana Machado (Jaju)!

Terminaram com mais de uma hora de vantagem para esta dupla brasileira no resultado acumulado, e mais de duas horas sobre as terceiras classificadas, a portuguesa Sandra Araújo e a italiana Lorenza Menapace (Round The Clock).

Parabéns às duas!

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A terceira parte…

Buyer’s guide to mountain bike suspension, part 3

Before suspension, which didn’t become mainstream until as recently as the late Nineties, mountain bikes were proper bone-shakers. On those old rigid-forked, rigid-framed bikes rough sections of track were exhilarating rollercoasters, but had you grimacing and your eyeballs rattling in their sockets.

When suspension was first introduced many riders turned up their noses at the ugly, heavy, flexy and very inefficient early designs. Nowadays it’s a different story; modern suspension bikes allow you to ride faster over uneven surfaces, further and for longer as they reduce impact and strain on your body. They smooth out ugly landings and save your bacon when you get out of your depth.

Suspension has two jobs on a bike: to keep the wheels in contact with the ground as much as possible to improve traction, and to cushion the impacts a bike deals with on rough terrain. If it’s not set up correctly, even a great suspension bike can feel like riding a mattress and really hold you back. Once you get your fork and/or shock dialled in, however, your riding will take a leap forward.

Suspension comes mainly in two forms: coil sprung or air sprung, although elastomers still get a look-in on low-cost forks. All suspension features compression and rebound damping to adjust the rate at which the fork or shock dives through its travel and returns. Cheaper shocks and forks may lack external adjustments, but it’s commonplace now for suspension to have at least external rebound controls.

Well set up suspension enables the wheels to follow the contours of the terrain by letting them drop into hollows and move around rocks and lumps. To do this, suspension is set up with sag – meaning your weight on the bike allows the bike to sit at a set point within the travel. Sag is usually set between a quarter and a third of the available travel.

Almost all forks and shocks share the same basic construction: a tube that slides inside a larger tube, with the spring and damping system contained within. Most forks are telescopic, and consist of two upper legs (stanchions) – joined by a crown – which slide in and out of a one-piece lower leg construction (sliders).

Most, but not all, forks have dedicated legs  (left or right) housing the damping and compression cartridges:

Rear shocks are a scaled down version, albeit with one leg, and in the case of coil shocks with the coil spring on the outside rather than inside (coil-over shock). As the fork or shock is compressed it squeezes the spring medium, which stores the energy then releases it as the fork/shock rebounds. Damping dissipates this energy and is used to finely control how the suspension behaves during compression and extension.

Fox anatomy fox’s float rp23 shock is the workhorse for most full suspension bikes on the uk trails:

Chassis

Forks and shocks are available in many shapes and sizes to suit the intended application, from cross-country racing to dirt jumping, and the rider. There are a number of standards to be aware of though, many of which may or may not be compatible with your setup.

Rear shocks are somewhat easier to get right – the frame has precise measurements that must be matched, such as shock eye-to-eye length, shock stroke and specific fitting hardware. Forks, however, have all sorts of differences. Modern fork steerer tubes come in three diameters: 1 1/8in (equals 1.125in), 1.5in and tapered from the latter measurement to the former (all beefier than the old 1in standard).

Which will fit your frame depends on the size of your head tube and headset. Tapered steerers are a recent development that combine the stiffness of the 1.5in width at the crown with compatibility with standard 1 1/8in stems, with hardly any weight penalty. They require a tapered head tube or special headset to fit.

As with forks, there are also a number of different types of axles. Most forks have 9mm quick-release (QR) dropouts, a carry-over from road bike technology. But in order to reduce flex, screw-through (also called through-axle) forks are becoming increasingly common. Like steerers, these require specific hardware, in this case a compatible hub.

The two main standards for screw/bolt-through axles are 20mm and 15mm, and hubs are available that can be converted between the two, and even from quick-release. Alongside the new axle standards, thicker, wider stanchions also increase fork stiffness and allow more precise steering, less twisting and reduced braking flutter, but the penalty for all this is increased weight.

Travel

Fork or shock travel – the total available compression – is typically between 80mm and 200mm (3-8in). More travel allows a softer spring rate and gives the fork/shock more time to deal with an impact, increasing the control over energy absorption. The amount you need depends on the intended use and what your bike is designed to handle, given its geometry. Check with the manufacturer before fitting new suspension so as not to invalidate your warranty or affect your bike’s handling adversely.

Springs

The spring stores the energy created when the shock or fork compresses. In cross-country forks it’s usually compressed air or it may be a metal coil. Air springs can be precisely adjusted to the rider’s weight and are lightweight, but air sprung forks can suffer from stiction (when the stanchions don’t slide smoothly in the lower legs because of flex in the fork) and resistance from increased sealing.

Unlike a coil, the spring rate increases as the fork compresses, known as progressive suspension, which can lead to the unit ramping up (becoming stiffer) at the end of the travel. Coil springs have an adjustable preload to set the ride height and sag, but the adjustment window is usually very narrow and often a change of spring is needed to get the desired results.

Damping

An undamped fork or shock would simply take the energy stored in the spring and fire it right back at you. Control is important, and that is achieved by forcing oil through ports and shims inside the stanchions to slow the action down.

Rebound damping is exactly that: as the fork or shock extends from a compression, it slows the rebound and turns the excess energy into heat as the oil is squeezed through the valves. Most forks and shocks will have an adjuster to precisely tune how fast you want them to rebound. Too much damping and the fork/shock will pack down (ie have less travel) over successive hits, too little and it will feel uncontrolled and bouncy.

Compression damping controls the fork/shock as it compresses, allowing it to react proportionately to different sized impacts. Slow-speed damping regulates movement such as brake dive, fork bob and excess compression in berms, while high-speed damping can prevent the fork/shock blowing through the travel (bottoming out) on big hits and drops.

Too much high-speed damping can be a bad thing, though – the oil pressure may build up causing a spike (when the oil can’t get through the ports or shims fast enough), which can be felt as a sharp knock. Sophisticated forks and shocks have shim stacks – thin washers that can bend out of the way – allowing the oil through and the fork/shock to move faster.

Lockout levers prevent the fork or shock moving, sometimes completely but many retain a little bit of travel to help traction. Lockout is useful on smooth climbs or road sections. Blow-off adjusters let you set the force of impact that will knock the lockout off to regain full travel. Not all forks and shocks have all these features, but the very least you need is rebound damping.

Jargon buster

Suspension fork terminology

  • Adjustment dial(s): Also called top caps. Besides allowing external adjustments – including compression, rebound, threshold and travel adjustment among others – the top caps seal the top of the stanchions/air springs.
  • Air valves: Depending on the fork, these can be for the main or supplementary air springs, the negative air spring or platform damping adjustment valve. Keep clean and check the valve core is tight if you get a leak.
  • Axle: This can be a regular 9mm quick-release, 20mm bolt-through or 15mm bolt-through. Now quick-release bolt-through axles, such as RockShox’s Maxle and Maxle Lite (20mm and 15mm for 2011 forks) and Fox’s QR15 (15mm), are increasingly being seen on cross-country and trail bikes.
  • Bushings: Synthetic slider guides for smooth telescopic action between upper and lower legs.
  • Crown: The ‘hips’ that hold the fork stanchions and attach to the steerer tube.
  • Dropouts: Traditionally forks used slotted 9mm dropouts for quick-release hubs, but with the new 15/20mm through-axle standards compatible forks have a hole rather than slot to slide the axle into.
  • Fixing bolts: Extremely important fork end bolts that hold the internal spring/piston rods in place, stop damping oil leaking out, and the whole lower leg assembly falling off.
  • Fork brace: An arch (or sometimes a pair on brands like Magura or DT Swiss) that stops the lower legs moving independently by preventing torsional flex to ensure good tracking.
  • Lockout lever: Stifles oil and air flow through the compression or rebound circuits to lock a fork rigid –  handy for climbing or spinning on the flat. Most have a blow- off (sometimes adjustable) valve to stop unexpected hits snapping your wrists.
  • Negative spring: Helper spring that opposes the main spring to help overcome seal resistance.
  • Preload adjuster: Increases the initial spring resistance of coil and elastomer forks. If you’re using more than several turns, consider the next spring weight up.
  • Rebound dial: External adjuster for the rebound damping circuit. May be on the top of the fork leg or at the base and is normally red in colour. Increasing rebound damping slows down the speed at which the fork leg returns after each hit; decreasing rebound damping speeds it up.
  • Remote levers: Fly-by-wire bar operation of one or more of the fork leg/ crown mounted adjusters.
  • Seals: Multiple wipers and lubricating sponges vital for keeping insides in and dirt out. Clean and check for damage often.
  • Slider/lowers: The moving part of the fork made of cast magnesium or carbon fibre. Big generally means stiff (on freeride/aggressive trail forks), skinnier generally means lighter/more flexible (cross-country forks).
  • Spring: Provides the basic up and down motion in air (light and easily adjustable), coil (ultra smooth and reliable), elastomer (cheap) or a mix of all three. Can be in one leg or both.
  • Stanchion: Slippery upper leg so the lower leg can slide smoothly over it. Occasionally steel, mostly aluminium and ranging from 28-40mm diameter, increasing in stiffness and strength as width increases. Watch for scratching or corrosion as this will rapidly ruin seals.
  • Steerer tube: Aluminium or carbon to save weight, or steel to boost strength and reduce cost. Come in a variety of sizes, with 1-1/8in being the cross-country standard and 1.5in steerers standard for freeride or downhill bikes. Tapered steerers (which taper from 1-1/8in at the top to 1.5in at the fork crown) are common on all-mountain or aggressive trail bikes where both stiffness and light weight are important.
  • Travel adjuster: Various travel adjustment systems are used by different manufacturers to let you change the amount of travel either on the go or when stationary. This can be useful for effecting geometry changes for climbing or descending.  The adjustment can be stepped (such as 100-150mm), incremental (3mm per click) or infinite (free adjustment anywhere within the range of travel) depending on the system, while other forks can be adjusted internally (such as to reduce a 120mm fork to 100mm travel only).

Rear shock terminology

  • Air valve: Schrader valve used for adding or removing air from the positive air spring on air shocks. Normally marked with a ‘+’ on it. Keep clean and check valve core is tight if shock starts to leak.
  • Bottom-out bumper: Simple bumper to stop a harsh clang at full compression.
  • Coil: Metal coil spring on coil shocks. Can be steel or titanium (for light weight), straight rate or rising/ falling rate. Spring weight (in ft/lb) will normally be printed on the side as well as the dimensions.
  • Compression adjuster: Dial or lockout lever that controls the compression damping circuit.
  • Eyelet: 6mm or 8mm hole at either end of the shock.
  • Length: Shocks come in various lengths. It’s measured from eyelet to eyelet (eye to eye length).
  • Lockout / low-speed compression: A damping circuit that resists compression from low-speed inputs like pedalling forces.
  • O-ring: Rubber ring on shaft showing the ‘tidemark’. Helps accurate sag set-up by showing how much travel is being used when sitting on the bike.
  • Piggyback chamber: Extra damping or air spring expansion chamber mounted parallel to the main body. Used mostly on all-mountain and downhill long-travel air shocks.
  • Preload collar: Only on coil shocks. Threaded collar that can be used to add additional load to the spring for a stiffer start. If you’re using more than 2.5 turns from contact we’d advise you get the next spring up.
  • Rebound adjuster: Controls the rate at which the shock extends after compression. Normally coloured red but can sometimes be blue. Check your manual.
  • Seal head: Wiper seals designed to keep the insides in and the outsides out. Check for any splits, embedded grit or other damage before it scars the shaft, and clean regularly if the shock can be dismantled (most air shocks can).
  • Shaft: The moving part of the fork made of cast magnesium or carbon fibre. Big generally means stiff (freeride/aggressive trail), skinnier generally means lighter/more flexible (cross-country).
  • Shock mount: Normally just a sandwich of alloy spacers but can be a spherical rose joint to reduce sideways stress. Check width is correct for your bike, check for wear/rattle regularly and replace immediately if this occurs.
  • Sleeve: Air-tight can that contains compressed air acting as a spring. Some are adjustable to change travel or internal chamber dimensions, and therefore the shock rat

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