Mais uma excelente iniciativa para os amigos do pedal.

—–

No final desta semana começa a ser distribuído o primeiro número do Pedal, um jornal gratuito mensal, que “pretende atingir toda a gente, especialmente os que ainda não andam de bicicleta. A temática do jornal é declaradamente sobre o mundo das bicicletas, não como objecto físico, mas sim como instrumento socio-cultural”, avançou ao M&P Bráulio Amado, director e um dos fundadores do Jornal Pedal.

Com cinco mil exemplares distribuídos em espaços comerciais e culturais de Lisboa, Porto, Aveiro e Faro, o Pedal está associado à cooperativa cultural Post (Lisboa), mas pretende funcionar como um meio independente.

Ao longo de 16 páginas, o jornal é constituído “por artigos, reportagens e entrevistas, mas também dando espaço à moda, arte, cinema, produtos e mecânica no mundo das bicicletas”, descreve o director.

Sem querer adiantar valores investidos neste projecto, Bráulio Amado refere que se trata de “um projecto que irá crescer a nível editorial à medida que a sua rentabilidade comercial lhe for proporcional. É um jornal gratuito e temos conhecimento dos condicionamentos a nível lucrativo que isso significa, e como tal estamos limitados às marcas que apostam em nós e fazem deste jornal possível, que nesta fase inícial já são o suficiente para existirmos”.

O projecto foi fundado por Bráulio Amado (designer a viver em Nova Iorque) Luís Gregório (designer), João Pinheiro (estudante e estafeta de bicicleta) e Filipe Gil (jornalista).

por meios e publicidade

 

Para quando termos estas soluções apreços realmente decentes?

—-

How much would you spend for an upgrade to smooth shifting on your next road bike? If $8,000 is in the ballpark, then Shimano-powered electronic shifters may be in your future. We took the cycling giant’s latest gear for a spin in Central Park, drawing envious glances from various spandex-clad bikers during the ride. Outfitted with the company’s newest Ultegra 6770 Di2 series of gears, the shifters gave us a taste of technology normally reserved for Tour de Francers — at new, more affordable pricing. So what was it like to be the envy of cyclists everywhere? Jump past the break to find out.

Many aspiring Lance Armstrongs will tell you that the future of bike technology is all about electronic gear-shifting. Unlike the traditional lever shifter, the electronic variety uses a motorized derailleur to move the chain from cog to cog. Thought by many to be faster, smarter and easier to use than a regular shifter, the electronic version only requires the click of a mouse-like button. The handlebar controls move both the front and the rear gears, giving the rider enhanced control over the ride with minimal effort. The shifter is powered by a removable lithium ion battery, which requires a 90-minute charge every 1,250 miles or so.

Even an amateur bike rider will be able to feel the difference between Shimano electronic gears and those on a standard road bike. The super sensitive shifter only requires a light press to move the chain in the front or rear derailleur and find the perfect gear. There’s no sticking or bumpy shifting, making the action smooth and effortless — getting the shift right every time. Of course, moving between gears may not be that big of a deal for those of us used to a Huffy, but when it comes to winning triathlons and road races, a smooth shifter is one of the key components to copping a gold medal to compliment your Lycra bodysuit. Expect to see Shimano’s new line of electronic gears in various bikes in the coming months.

 

Travões de bicicleta sem fios!

On 2011-10-17, in Blog, by Tigas

Parece-me mesmo uma grande ideia … os quadros ficam mais limpos e mais rigidos!

Vamos ver se pega…

________

Investigadores alemães desenvolveram travões de bicicleta que usam tecnologias de redes sem fios. O protótipo funciona em 99,999999999997 % das vezes em que foi usado.

Inventado travão de bicicleta sem fios

Os investigadores da Universidade de Saarland tiraram os cabos aos travões e substituíram-nos por comunicadores de redes sem fios.

Em vez dos tradicionais manípulos dos travões, o guiador do protótipo dispõe de punhos com sensores incorporados, que enviam sinais aos discos dos travões que se encontram junto às rodas, sempre que o utilizador contrai as mãos.

Os investigadores tiveram de sujeitar o protótipo a testes exaustivos, a fim de criar um sistema suficientemente seguro e fiável: “Num bilião de tentativas de travagem apenas tivemos três falhas. Não é perfeito, mas é aceitável”, referiu o mentor do projeto Holger Hermanns.

Aos que receiam andar em bicicletas que usam travões sem fios, o investigador alemão responde que se trata de apenas um primeiro passo para testar o potencial desta tecnologia que pode servir de base para futuros testes com travões de… comboios e aviões.

Ler mais: http://aeiou.exameinformatica.pt/inventado-travao-de-bicicleta-sem-fios=f1010850#ixzz1b2DPoZnq

 

e-bike de Gabriel Wartofsky

On 2011-09-27, in Blog, by Tigas

Mais um projecto a seguir ….

Com esta ia todos os dias para o trabalho…

—-

Wartofsky successfully funded this e-bike through KickStarter

No matter how great or innovative an idea, these days it takes considerable investment to bring it to market. Traditional bank loans can be hard to come by and venture capital can steer an innovator away from their original intent. In light of these challenges, award-winning e-bike designer Gabriel Wartofsky has taken a unique approach towards raising funds to jumpstart US manufacturing for his bikes.

Fittingly he launched a KickStarter campaign, to raise the capital needed, which, so far, has raised US$500 more than his goal of $25,000. KickStarter is an Internet funding platform that allows potential users to actually be involved in funding a product they believe in. “KickStarter provides many advantages to us,” Wartofsky tells BikeRadar. “KickStarter’s pledgers tend to be highly influential people, early adopters who set the trends within their circles and communities. These supporters help spread the word to other potential supporters who trust their taste and guidance.”

Furthermore the KickStart program can provide a high level of exposure and validation points, which can in turn court other investors. “If we’ve made it on KickStarter, we know that we have a relevant, fun project,” adds Wartofsky. “We also know that many other people now know this, too!”

But this doesn’t mean that investors have to be professional venture capitalists or Wall Street players to take part; Wartofsky notes that the programs allows for supporters to pledge from $1 on up, so people who are tight on cash can still participate. Additionally, this investment system also doesn’t require that the innovators have to sell their stake in the company or their metaphorical souls either. “KickStarter does not require that we have to give up shares to investors,” says Wartofsky, adding, “Therefore, our idea can stay under our guidance, with no risk of losing control to another party.”

Wartofsky's e-bike is a folder: wartofsky's e-bike is a folder

Wartofsky’s folding e-bike

E-bikes could also play a crucial role in getting people to consider alternative methods of commuting in America, where in most cities cars are still kings of the road. Wartofsky believes that e-bikes might encourage people to try using bicycles as an alternate form of transportation for their daily commutes. “Many people would like to diversify the way they get around in cities, but are often hindered by the need to arrive at a destination looking presentable,” says Wartofsky. “Many work places are not equipped with showers, and people don’t want to start their day with the hassle of changing clothes at their workplace, risking chain grease stains on their fingers and clothing, and finding a safe, appropriate place to park their bikes.”

The electric assist bike empowers users to get to the nearest transit hub or final destination sweat-free, grease-free, and without a hassle, says Wartokfsky. Plus, the e-bikes that he is helping develop can simply be folded up, stored beside a desk, under their bus seat, or in the trunk of a car. But beyond commuting, e-bikes could offer other opportunities for Americans, especially as the price at the gas pump doesn’t look like it will drop anytime soon.

“Many consumers don’t know how to initially justify the higher price of a good electric bike,” says Wartofsky, adding that he is approaching this in a few ways, including b by raising awareness of the fact is that e-bikes end up saving their owner’s a lot of money. “Less fuel, less car-related costs. According to the American Public Transportation Association’s monthly Transit Savings Report, if coupled with public transit, individuals save, on average, $9,968 annually and $831 per month.”

In addition to trying to undercut the competition, Wartofsky is looking at rental and bikeshare applications, which will increase access to e-bikes to people who can’t afford the initial costs. Additionally, cities and corporations who fund these bike shares end up saving by reducing costs via many tax incentives and infrastructure projects including parking lots.

The final key to Wartofsky’s plan is to address a big issue with e-bikes, what he calls the “need to have one” design. “They generally look like rolling science projects. People enjoy personal transportation for reasons outside of the inherent practicalities: they also want to look good, and own nice things.”

The design's specifications: the design's specifications

KickStarters micro-financiers bought into Wartofsky’s folding e-bike concept

He adds that good design is actually about simplicity, so that the bike can be comfortable to ride, pleasant to look at and easy to store. “Bicycles are a joy to ride, and have applications beyond the recreational: they are practical, efficient machines that enhance the quality of your life and environment,” says Wartofsky. “We aim to make them more practical for the mainstream user who would like to ride a bike, but can’t afford the aforementioned compromises.”

 

Concept bike electrica da Ford

On 2011-09-13, in Blog, by Tigas

Mais uma concept bike electrica, desta vez da Ford.

—-

Ford E-Bike Concept

Ford already wowed us with the Evos concept, but the slinkiest hybrid we’ve seen so far here in Frankfurt has not four wheels but two. It’s a concept bicycle from Ford called — wait for it — the E-Bike Concept. It packs an electric motor built into the front wheel that can power it up to a maximum speed of 25 km/h, driven by a 9.2Ah battery. Or you can power it the conventional way by pedalling, torque conveyed to the rear wheel over a carbon belt. (Oily chains are so last century.)

Perhaps even more interesting is what rests up on the handlebars. No, that’s no iDevice — refreshingly it’s a Galaxy S II. Through some custom software, riders will be able to change suspension modes and of course monitor battery charge, not to mention get a little assistance from Google Navigation and maybe pump out some Pandora too. The word “Concept” in the title here and the spindly frame design should give you a clue about when this thing will see production — probably never. But, we’ll be back with an update if that ever changes.

 

Novidades SRAM X5 com 10 velocidades …

On 2011-08-31, in Blog, by Tigas

É a verdadeira democratização da opção de 10 velocidades, depois da Shimano, a SRAM apresenta agora o X5 de 10 velocidades.

Fica o review…

SRAM have unveiled an updated, 10-speed version of their X5 mountain bike groupset ahead of this week’s Eurobike trade show. We’ll bring you the full lowdown from the show, but for now here are some pictures and brief details.

Availability is slated for late autumn 2011, and there’s no word yet on UK pricing. Compatibility with SRAM’s higher-end 10-speed groups means mix-and-matching parts is now a possibility. Check out www.sram.comfor more.

X5 rear derailleur

  • Exact Actuation with 1:1 ratio
  • Direct Route Technology (no cable loop) for lighter shifting
  • Compatible with 36-tooth cassettes
  • Choice of long or medium cage

SRAM x5 rear derailleur: sram x5 rear derailleur

X5 trigger shifters

  • Rear shifter is nine- and 10-speed compatible, front is available in double and triple versions
  • Impulse Technology
  • MatchMaker compatible

SRAM x5 right-hand shifter: sram x5 right-hand shifter

X5 front derailleur

  • Available in 2×10, 3×10 and 3×9 versions
  • Clamps to fit 31.8 and 34.9mm seat tubes
  • X-Glide technology for smooth shifting
  • Dual-pull routing

SRAM x5 front derailleur: sram x5 front derailleur

X5 crankset

  • Double (36/22, 38/24, 39/26 or 42/28-tooth) and triple (44/33/22T) versions available
  • X-Glide technology for smooth shifting
  • Asymmetric forged 6061 alloy arms, 7075 alloy chainrings
  • Giga X Pipe (GXP) XR bottom bracket with steel bearings and Gutter Seal Technology
  • PF30 and BB30 options available

SRAM x5 crankset: sram x5 crankset

PG-1030 cassette

  • 11-36T
  • Aluminium spider, steel sprockets and lockring
  • Durable nickel chrome finish
  • PowerGlide Technology for smooth shifting

SRAM pg 1030 cassette: sram pg 1030 cassette

 

Merida 0.9 Team

On 2011-08-21, in Blog, by kreisp

Ao fim de muitos anos de BTT (15+), chegou a minha vez de mudar para um quadro de carbono :)

Depois de muita ponderação acabei por adquirir um dos mais conceituados – Merida 0.9

Com mais de 15k kms troquei a Scott Scale de alumínio igualmente por um quadro rígido, mas com características diferentes.

A montagem com todos os componentes que tinha ficou abaixo de 10kg.

Agora é tempo para pedalar e aproximá-la dos 9,5 kg.
Para o meu peso e estatura é um objectivo sensato.

Quadro Merida 0.9 Team Edition 21.5″
Suspensão Fox RL 100 Remote Lockout 2009
Caixa de Direcção FSA
Pedaleira Shimano XT
Travões Shimano LX Dual Control 2006
Discos Travao Shimano LX
Cassete Sram PG970
Desviador D Shimano SLX E-Type
Desviador T Shimano XT Shadow
Manetes de Mudança Shimano LX Dual Control 2006
Pneus Schwalbe Rocket Ron Performance 2.1
Selim Selle SMP Hybrid
Espigão Selim Cannondale Save
Guiador KCNC SC Bone
Avanço Ritchey WCS 120 mm
Punhos Ritchey Esponja
Pedais Exustar E-PM25
Corrente Sram PG971
Porta Bidons Plástico Specialized
Rodas Shimano XT WH-M775

 

Transmissões – Guia do iniciado

On 2011-08-21, in Blog, by Tigas

Mais um artigo interessante sobre transmissões…

—–

It is amazing to think that just 30 years ago the mountain bike drivetrain didn’t even exist. It wasn’t until 1982 that Shimano launched the iconic six-speed XT component group, and even this high-end equipment didn’t feature the basic stuff that we take for granted today, such as indexed shifting and slide on cassette sprockets.

Gears is an area that has seen rapid development over the years: the fundamentals may be very similar, but with manufacturers pushing their new technologies and releasing 10-speed parts in a host of configurations, the modern mountain bike transmission is a world away from its forefather. Confused? Read on as the twisted chain of cogs, mechs, shifters and crank arms is slowly unravelled.

The need for speed

Why do we even need gears, and why so many? The simple answer is that not all of us do. People have been riding singlespeed since the bike was invented and continue to do so for many reasons such as mechanical simplicity, low weight or just easy terrain that doesn’t demand so many cogs. However, ultimately we are all limited by one thing – the human powerplant.

The power we output is simply a function of torque (how hard we pedal) and cadence (how fast we pedal). Our muscles are most efficient at sustaining a cadence of somewhere between 60 and 120 crank revolutions-per-minute. Changing gear allows us to stay in that optimum range and tailor our output for the variety of speeds and terrain we will encounter.

A motorbike engine for example can supply its torque over a much larger rev range, and for that reason doesn’t need quite so many gears. Also, as we’re powered by cakes rather than petrol, the supply of energy to fuel our engine isn’t always as smooth as we would like. Efficiency is key, and over pushing a gear that is too hard, or over spinning too easy a gear can lead to fatigue or muscle strain very quickly.

Gear systems and ranges have evolved over the years to reflect how we ride and the changes in the types of bikes on the market. Mountain biking is no longer just the cross-country orientated sport it was in the 1980s. With the advent of downhill at the end of the last century, and the introduction of all-mountain go-anywhere machines at the beginning of this one, manufacturers and riders soon realised a change in direction was needed.

The large touring-inspired triple chainsets that were standard on nearly all bikes were replaced with smaller, compact versions that provided greater clearance. Wider ranging cassettes with more sprockets were introduced, not only to provide higher and lower gears, but to reduce the gap to the adjacent gear for more precise cadence control. Harder hitting bikes often lost the front shifting altogether or used a double ring crank and guard for powering down hills with rock clearing confidence.

The biggest leap forward in mountain bike drivetrain technology since Shimano launched the Mega Nine equipment in 1999 is 10-speed. Both Shimano and SRAM have released 10-speed groups at a variety of pricepoints, but rather than push the benefits of that single extra cog they’ve looked more in depth at how it integrates with the front shifting. By understanding the basics of how transmission works and the pros and cons of different setups even the novice rider can make an informed decision on what is best for them. Whether that be seven, eight, nine, 10, or just the one gear!

Bottom bracket houses the crank bearings; make sure yours is compatible with the frame and chainset: bottom bracket houses the crank bearings; make sure yours is compatible with the frame and chainset

Derailleurs and drivetrains uncaged

The bicycle derailleur, or mechanism (mech), was envisaged as long ago as the late 1890s, but it wasn’t until the 1930s that the familiar parallelogram shape was born. Suntour revised the design for rear mechs in 1964, and it’s this layout that survives today, albeit with a few tweaks. That dangly piece of metal that hangs off the back of your bike has quite a few tasks to perform.

As well as moving the chain up and down the cassette in precise increments, it must also compensate for the change in chain length as we shift, and keep the chain under sufficient tension. It does this by using a sprung parallelogram off which hangs a cage. This cage contains the top guide pulley and the bottom tension pulley, and moves in and out of the frame, taking the chain with it. A second spring pulls the cage to tension the change, while the whole mechanism is connected to the frame via a rotating link.

The front derailleur works on a similar principle, with a linkage to shunt the chain back and forth, albeit this time without any tension duties to perform. Both mechs have two screws to limit the overall movement (preventing the chain derailing completely).

None of this can happen without the shifters. Housed in the familiar ‘pods’ that bolt onto the bars, a ratchet and lever system pulls the chain in set increments that result in a gear change. It hasn’t always been this way though – indexed shifting (one click per gear change) wasn’t fully realised until 1984. Before that we relied on a simple friction system to adjust the derailleur action. Setting the correct cable tension is the key to precise shifting, with the barrel adjusters on the shifter body allowing for fine tuning.

So, how does the chain actually jump to the next cog or sprocket? If you look closely at your cassette and chainrings you will see a series of ramps and pins. These are located in specific places to allow the chain to climb and drop to the next gear smoothly and quickly. Some systems, such as the Dynasys equipment from Shimano even have directional chains that take this concept a step further.

Ramps, pins and cut-outs help the chain shift from ring to ring: ramps, pins and cut-outs help the chain shift from ring to ring

Combinations and limitations

The drivetrain you end up with will depend on a few factors, not least your personal preference. The terrain, preferred cadence, your bike and strength/weight will all influence what you choose and you will often find that you have two different setups on two different bikes.

If you want to climb every mountain and nail every descent then a wide ranging gear set with triple chainset could be the perfect compromise. If you’re a cross-country racing snake with tree trunk legs you may want to drop the granny ring altogether and favour a large double chainset with close ratio cassette. Alternatively simplicity may be your thing so a single ring could be the ideal solution, but if you value a bit of clearance on your all-mountain mosher, a smaller twin front set-up with bash guard will tick all the boxes.

More sprockets can increase your range and the step between each gear. On the flipside, too less a step may result in you making more changes. Twin chainrings can provide a more usable range of gears but limit the absolute top and bottom end, though smaller rings can provide great log clearing capabilities.

Even before 10-speed was thought of, there has existed a large variety of chainset and cassette combos at the seven-, eight- and nine-speed level. Cogs with 34 teeth started to appear on cassettes at the turn of the century, and companies such as Ritchey and Middleburn were experimenting with proprietary double chainset systems even before then. Triples have been tweaked a few times with some interesting and odd combinations.

Ratios

A typical gear system may have three chainrings in a 44/32/22 format and eight or nine sprockets on the cassette, usually 11-32. The smallest rear sprocket equates to the hardest gear, while at the front this is reversed. The gear you’re in is a simple ratio of the number of teeth on the chainring to the number of teeth on the sprocket in use. For example, with a 32-tooth ring and 16-tooth cog your ratio is 2:1 (32/16).

However, the size of the wheel has to be taken into account to determine how hard that gear actually is. Multiplying the gear ratio by the wheel diameter gives us a number called the gear inch. This allows us to compare gears across a wide range of wheel sizes, for example comparing an average 29er bike to an average 26in-wheeled bike, with exactly the same gearset, the 29er will feel about 10-11 percent harder to pedal. The total range of your gears is simply a comparison of the lowest ratio to the highest and is often expressed as a percentage.

Limit screws prevent the chain from derailing off the cassette: limit screws prevent the chain from derailing off the cassette

A quick look at our typical triple chainring will reveal something that at first glance seems rather odd: a lot of the gear ratios are duplicated! The 32/16 combo will pedal pretty much the same as the 44/22 and 22/11. In total there may only be 13 or 14 unique ratios across the whole gearing range. The reason for this is the physical limitations imposed by the gearing.

Front mechs can only handle jumps of around 12-14 teeth in one gear change, and because of the angle the mech moves at, a minimum number is usually quoted too. This isn’t always a bad thing. If the mech could jump say 20 teeth in one go you might find that the gear change is simply too much and you have to make numerous ‘recovery’ shifts at the rear to get the next gear you wanted. Smaller steps in the chainring sizes may cause more overlap, but can provide a more economical gear change, and using certain sprocket/ring combos can cause the chain to lie at an angle, increasing wear and tear.

Cassette

The same questions can be asked of the cassette. Why limit our choices to 11-32 or even 11-36 as found on some newer drivetrains? Why not use a range like 6 to 42 teeth for a huge sequential range? Again it comes down to technicalities involving the drivetrain equipment. The modern sprocket cluster slides onto a unit called a freehub body, which houses a freewheel mechanism and the hub bearings. The physical size of this has limited the size of the smallest cog to 11 teeth.

Derailleur specifications can’t handle a sprocket larger than 36 teeth, which is why currently the widest ranging cassettes we see are the 11-36. Also the smaller the rear sprocket gets the less efficient the drive will become. By weighing up all the options, studying the numbers and even testing a few groupsets out, you can quickly familiarise yourself with the choices and make the best decision.

Shift to the future

Will we stop at 10-speed? With Campagnolo already releasing 11-speed on their road groups it seems logical that mountain bikes will eventually follow suit with the ‘more is better’ mantra. There have been some interesting developments with cassettes, with Shimano redesigning the freehub body to allow a nine-speed sprocket to be fitted, and Hope achieving a very similar result with a proprietary system.

It seems that wider ranges are at the forefront of developers’ minds with pushes towards systems that may do away with front shifting altogether. Some hub gears have already realised this, and no doubt we will see more planetary drives and gear boxes popping up over the next few years. We may even see instantly shifting Continuously Various Transmission (CVT) appearing on bikes in the future with a few people working on this concept.

Will the derailleur itself disappear at some point in the future? When it works, it works great, but show it a stick or any other trail gremlin and it is rather prone to self-destruction. One thing’s for sure, we will have more choice, even if the parts are not necessarily better. And more choice allows us to tailor our bike ever more towards that holy grail of riding perfection…

Transmission set-ups have evolved to reflect how and what we ride these days: transmission set-ups have evolved to reflect how and what we ride these days

Mountain bike drivetrain components explained

Cassette: The cassette is basically a pile of different sized sprockets that make up one half of your gear system. They mount onto the freehub body of the wheel, and are locked down with a specific ring. If you have an alloy freehub body look for alloy spiders on the cassette as this will prevent scarring and damage

Chainset: The chainset forms the second half of your gearing, usually comprising of one, two or three rings joined to the crank arms via a spider. Different lengths are available to suit different lengths of leg, as well as a variety of bottom bracket fittings, just check what your frame takes.

Rear derailleur: The rear derailleur shunts the chain up and down the cassette as well as taking up chain tension differences between the ratios. Longer cages can handle a greater range of gears, but shorter lengths can mean less rattling and a snappier shift.

Front derailleur: The front derailleur handles shifting duties across the chainset and acts as a retainer for the chain. Different mounts and cable entries are available depending on the needs of your frame. Look out for specific versions to tailor shifting ie for double chainsets or very large chainrings.

Shifters: The shifters perform the magic, hauling a cable through the outers, eventually operating the derailleurs. Trigger shifters with paddles are most common, but twist type and brake levers that double up as shift levers are available. The number of shifts must match the number of sprockets on your cassette.

Chain: The chain combines with the shifting ramps and pins on the sprockets and rings to enable it to smoothly change between the gears. Always ensure it is the correct length, and fit direction chains appropriately – wrap the chain around the largest cog and largest sprocket (bypassing the derailleurs), and add two links where they overlap.

Devil in the detail

Pay attention to the individual specifications of the items in question. Front mechs are available in a number of clamp types, cable entries and cage heights so ensure it fits your frame and double check it can cope with the range of gears and size of rings you are using. Similarly for the rear mech; most bolt on the same way but there are always exceptions.

The cage length depends on the capacity of your system (the difference in number of teeth on your very highest and very lowest of gears). Most rear mechs will state this, as well as the actual largest sprocket it can handle. In many cases you can actually get away with going over the prescribed specs a little, but with so many combinations out there, always err on the side of caution and always ensure the chain is the correct length. Bottom brackets have many standards from the simple cartridge type to press-fit external bearings. Your frame will dictate much of what fits and what doesn’t.

What do the shiny bits of kit actually do?: what do the shiny bits of kit actually do?

Compatibility

With seven-, eight- and nine-speed formats having been on the market for over a decade, well established rules have emerged on how different kit integrates together. While it is pretty obvious that your indexed shifters must match your cassette for speeds, it’s less well known that the ‘speed’ of the derailleur doesn’t have to match shifters or cassette as the cable pull ratios remain the same.

Well, at least for the same brand. The brand of shifter has to match the rear derailleur. With SRAM shifters pulling twice as much cable per click than Shimano, you can’t use Shimano shifters with SRAM derailleurs and vice versa. Front mechs are fully interchangeable though, except for a little rubbing with the narrower cages of the higher speed stuff on the lower equipment. Similarly almost all chains, regardless of designated speed, seem to work perfectly well on eight or nine-speed cassettes and chainsets despite slightly different dimensions.

The introduction of 10-speed has thrown a big oily spanner in the spokes, with a lot of this compatibility not being carried forward. Shimano and SRAM have tweaked the cable pulls, so that 10-speed shifters must match their own 10-speed derailleurs. Interestingly, front derailleurs seem to work fine with any brand and any designated speed, but there is no doubt that matching for speeds across the parts results in less rubbing.

If you must mix, try and mate the derailleur speed to that of the crankset. Similarly chains work best when in their own group, but using a higher speed chain on lower named cranksets works fine – though keep the chain matched to the sprockets for best results. Also remember that all cassettes bar seven-speed will fit on a modern freehub body as the sprocket spacing gets progressively narrower, and if you do use a seven-speed cassette, a 2.5mm spacer must be fitted first.

Perfect 10?

SRAM first released a 10-speed groupset a couple of years ago, aimed squarely at racing with their flagship XX kit. The technology has now trickled down to the mid-range X7 level. Shimano have hit back with 10-speed groups from SLX level all the way up to the top of their tree, XTR, for the 2011 season. A 10-speed cassette with a 36-tooth sprocket is where the similarities end, as each company has pushed different concepts revolving around the chainset.

Shimano champion the triple configuration. By reducing the largest ring to 42 teeth and increasing the smallest ring to 24, Shimano propose riders are more likely to stay in the middle ring with that dinner plate sized 36-toother at the rear. When you do shift down into the granny ring or up into the large ring, the smaller jump will equate to less recovery shifting and a more efficient ride. Shimano also claim that full-suspension systems will suffer from less bob due to the optimised chainline.

SRAM, on the other hand, push the double chainset, or as they put it, the 2×10. By pairing the chainrings in a 3:2 ratio (42/28 and 39/26) with perfectly timed ramps and pins, SRAM have increased the front shifting speed and fluidity. A variety of cassettes are offered, not all with the large 36-tooth option though. SRAM claim that the advantages of such a system are simplicity, lighter weight and a perfectly suitable range of gears that are fast changing and easy to use for all riders.

SRAM's 10-speed groupset tech features across its range:

Alternative systems

The hub gear is an age-old solution that comprises of an enclosed planetary cog assembly inside the rear hub. A standard looking shifter and cable is used to shift the cogs about while a normal chainring and sprocket is utilised to drive the system. The enclosed system resists the elements and requires little maintenance. However, the design can add weight and mechanical efficiency isn’t always as high. The range can be also low, but companies such as Rohloff and Shimano with their Alfine products have upped the ante, reproducing useful gear ranges and lowering weight to near that of an equivalent priced derailleur set-up.

Planetary drive gears aren’t just limited to the rear hub. Truvativ made big waves with their twin-geared HammerSchmidt front chainset. Chains aren’t even needed in some cases – a small number of bikes have appeared using belts with their planetary drive gear sets. Even electronics have found their way onto bikes. Shimano Di2 has been on road bikes for some time now with rumours abounding that we’ll see it on mountain bikes at some point in the future.

Problems and cures: Make your shifting sweet again

You’ve probably noticed that bicycle transmissions are complex things. Hub gears hide their parts inside their shells and have maintenance needs more akin to a car than a bike. You change the oil every so often and if anything goes wrong enough to need further intervention it’s time to seek out a specialist.

Derailleur systems wear their moving parts on their sleeves. Having everything out in the open is something of an anachronism in wheeled vehicles, but with exposure comes accessibility, and that’s one of the reasons that derailleurs still dominate bike transmissions. Cleaning goes a long way to keeping things sweet, but sometimes something will go badly wrong and need mending.

The most common problem is slow or hesitant shifting at the rear. Reluctant downshifts (to larger sprockets) are often the result of cable stretch and can quickly be dialled out by turning the barrel adjuster on the mech or at the shifter. Wind the adjuster out (anti-clockwise) a quarter-turn at a time until everything’s happy again. If you go too far, upshifts (to smaller sprockets) will become slow, so turn the adjuster back in again, being careful not to overshoot the other way.

If you can’t get snappy shifting in both directions, something else is wrong. The usual cause is drag in the cable – when you upshift, the derailleur spring has to pull the slack cable through, and any stickiness in the cable run will impede that. Stick the bike on a workstand, shift into the biggest sprocket and then click the shifter all the way back the other way, but without turning the pedals. This will give you enough slack to pop the cable housings out of their stops, allowing you to slide them along the cable and give it a degrease and wipe clean. A bit of light oil sprayed down the ends of the housings should see everything sweet once more.

While the cable’s exposed, check for kinks or frayed strands. Inspect the housing too. Outer cable rubbing against the frame can lead to the wire strands bursting out, and sometimes the ferrules at the end of the cable can split or crease. If the cable checks out, turn your attention to the rear derailleur. Possible issues include a build-up of dirt, a broken spring stopping it springing back, a bent cage, worn jockey wheels or sloppiness in the parallelogram linkages. Eventually, mechs get sufficiently worn that most of the cable pull just drags the slop out of the links rather than moving the cage sideways. And, of course, a heavily worn chain or cassette won’t run smoothly either.

The final possibility is a bent derailleur hanger on the frame itself. That’s easy to spot – it should hang straight down. If it’s bent, don’t panic. The hanger normally bolts on and is easily replaced. Even if it doesn’t, it can usually be levered straight. You can do this with two spanners, a good eye and nerves of steel, but it’s best to take it to a competent bike shop and let them use the proper tools.

Tip 1: Start with the barrel adjuster to dial out any cable stretch

Problems and cures: tip 1: problems and cures: tip 1

Tip 2: Light oil at the end of the housings will help ease cable drag

Problems and cures: tip 2: problems and cures: tip 2

Tip 3: Check the cable for damage or fraying and replace if needed

Problems and cures: tip 3: problems and cures: tip 3

Tip 4: The rear derailleur is the next place to look for grime, wear and tear – adjust where necessary

Problems and cures: tip 4: problems and cures: tip 4

Tip 5: If you still can’t get a smooth shift, re-tension the cable and run through these tips again

Problems and cures: tip 5: problems and cures: tip 5

 

Finalmente Sub 11 – Objectivo conseguido

On 2011-08-15, in Blog, by Ruben

Tal como prometi, aqui fica a Genius com as rodas novas.

10,88kg, nada mau ;)

Mais detalhes no link do projecto: Genius

 

Pois é, à medida que se vai tornando mais popular o 2×10 “inventado” vamos tendo cada vez mais alternativas “reais” a bom preço.

Já tinhamos o SLX da Shimano e agora é a vez da SRAM apresentar o X9 2×10. Esperamos uma qualidade excelente e um preço convidativo …

SRAM X9 transmission

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First impressions of the latest SRAM X9 kit weren’t the best – with a slightly bent rear mech cage and rattly shift levers, expectations were somewhat muted. The double chainset in this 39/26-tooth flavour is worthy of being in the SRAM upper echelons, though.

With its sleek looks, light weight and decent stiffness, it performs well – as does the cassette, which echoes the looks of the pricier X0 with its cutouts and drillings, though the soon to be released 11-36T version will be welcome. The shifters keep the clean looks, but the feel was atypical of SRAM, with shifts into larger cogs feeling less crisp and more stodgy than its rivals.

Changing to smaller sprockets felt better with that trademark ‘snap’, though the levers could take a bit of effort to shift. Shifting under power was impressive, a bonus as you do tend to work the X Glide twin rings more than a triple setup.

 
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