Pagar promessas?

On 2011-04-28, in Blog, by Dany

Hoje saí de casa para pedalar, como quase todos os dias. A única diferença foi a de estar de férias.

Resolvi fazer-me à estrada eram cerca das 8 da manhã! Primeiro erro. Aliás, primeiros erros. Estrada e 8 da manhã! Pois…é a hora do pessoal que trabalha estar a sair de casa.

Depois quis fazer 120 km! Grande maluquice, é verdade. Sinceramente nem eu sei bem a razão. Só sei que os queria fazer apesar de ter perfeita noção da minha pouca preparação.

Contra todas as adversidades; lá fui!

Ao fim de 2 horas tinha já 62km, não era mau, tendo em conta o trânsito que tinha apanhado e alguns sinais vermelhos.
Ao contrário do que eu esperava estava com mais cansaço muscular que aeróbio. Talvez pelas subidas que tinha feito ontem na Guarda (vai haver vídeo :) ).
Nesta altura já cansado, resolvi parar para comer a banana que tinha metido na bolsa. As pernas agradeceram, assim como o estômago.
Cerca de 4 minutos depois, voltei à estrada.

Desta vez os km começaram a render mais! Aos 85 e já com 3 horas parei assim que vi um café. Já estava muito cansado. O selim começou a ser muito incómodo. A bebida já se tinha ido quase toda. No café pedi uma Cola e uma garrafa de 1,5 litros de água fresca.
Bebi a Cola, acabei a segunda garrafa que levava comigo e enchi ambas com a água fresca.
Ainda me faltavam 40km…

Não era agora que ia desistir!

Voltei à estrada e começo a ver vários peregrinos já a caminharem para Fátima para pagarem as suas promessas. Penso para com os meus pedais “será que também ando aqui a pagar promessa?”. Mais parecia…

Em jeito de conclusão, posso dizer que comecei e acabei. Não foi em 4 horas, mas foi em 5.
Ao almoço uma grande pratada de massa com atum e dois ovos estrelados!

Neste momento estou a colocar gelo nas pernas, porque a “brincadeira” foi bastante parva mesmo sem mencionar os valentes sustos que apanhei devido aos camionistas! Sim, nunca, mas mesmo nunca, andem por estradas onde passem camiões.

A foto do GPS mostra a história. Cerca de 5 horas, 123km e 4400kCal gastas.

GPShttp://danyemviagem.blogspot.com/2011/04/pagar-promessas.html

 

5 razões para pedalar até ao trabalho!

On 2011-04-28, in Blog, by Tigas

5 razões para pedarlar até ao trabalho!

Confesso que quando li o título deste artigo pensei em mim próprio e na ideia de pedalar até ao trabalho, mas as condicionantes são tantas que nem sei por onde começar…

Os filhos, o facto de não existir um sítio para guardar a bicicleta ou trocar de roupa no edifício onde trabalho, a poluição do centro de Lisboa, o facto de não ter uma bicicleta preparada para a cidade…

Vou continuar a pensar no assunto ;)

—-

Longer life, improved health, more energy, lower costs and extra fun… It’s official – cycling makes you a better person in many ways. Here are just a few reasons, along with some compelling stats, to cycle to work

1 Feel happier

Apart from the increased self-esteem and confidence that getting fitter and leaner will give you, simply spending more time outside will cheer you up. This is thanks to the ability of sunlight to boost your levels of the feel-good hormone serotonin.

So if you want to beat the depressing effect of sitting in an artificially lit office, you should get outside to expose yourself to more daylight. The recommended office lighting is only about 300lux, whereas the strength of the sun measures over 1000lux even on overcast days. Full daylight (not directly in the sun) is 10,000-25,000lux. So go on, get out there!

The other major benefit of getting more daylight in your life is that you’ll sleep better and longer. Stanford University School of Medicine researchers asked sedentary insomnia sufferers to cycle for 20-30 minutes every other day. The result? The amount of time the insomniacs took to fall asleep was reduced by half, and the time they spent asleep increased by almost an hour a night.

“Exercising outside exposes you to daylight,” explains Professor Jim Horne from Loughborough University’s Sleep Research Centre. “This helps get your circadian rhythm back in sync and rids your body of cortisol, the stress hormone that can prevent deep, regenerative sleep.”

Feel happier: feel happier

2 Live longer

“Our research found that those who exercise regularly are at significantly lower risk of cardiovascular disease, Type II diabetes, all types of cancer, high blood pressure and obesity,” says Dr Lynn Cherkas of King’s College London.

The research compared over 2400 identical twins and found that those who did the equivalent of three 45-minute rides every week were ‘biologically younger’ by nine years, even after discounting other influences such as body mass index (BMI) and smoking.

According to the British Heart Foundation, around 10,000 fatal heart attacks could be avoided each year if people kept themselves fitter. Studies from Purdue University in the US have shown that regular cycling – even as little as 20 miles a week – can cut your risk of heart disease by up to 50 percent.

Cycling can even protect you from the big C, according to Harley Street gastroenterologist Dr Ana Raimundo. “Physical activity helps decrease the time it takes food to move through the large intestine, limiting the amount of water absorbed back into your body and leaving you with softer stools, which are easier to pass,” she says.

Doing aerobic exercise such as cycling also accelerates your breathing and heart rate, which helps to stimulate the contraction of intestinal muscles and keep you more regular. “As well as preventing you from feeling bloated this helps protect against bowel cancer,” explains Dr Raimundo.

Live longer: live longer

3 Travel cheaper

According to the RAC, the yearly cost of car ownership in the UK is about £5,869, the lion’s share of which is down to fuel. Today, petrol costs roughly £1.29 per litre and diesel £1.34 per litre, with both figures rising to record highs, says the AA. So should we be letting the buses and trains take the strain? If only.

Public transport costs have gone skyward too and the solution hundreds of thousands are turning to for daily travel, just as in the ’70s, is the bicycle. With cycling, the only inflationary factors are the rising cost of food and the payouts for your bike and kit. But you have to eat anyway, and the cost and depreciation on a new bike is at worst measured in hundreds of pounds, compared to the thousands lost on a car.

Transport for London estimates that the number of cycling journeys in the capital is up 117 percent since 2000. But this is just a drop in the ocean when you consider there are about 7 million people in the UK who make work-based journeys of under five miles by car or bus every day. Cycling England – the soon to be defunct Department for Transport quango tasked with promoting cycling – reckons they could each save upwards of £500 a year if they rode instead.

We could even make headway to reducing the national debt by cycling. Modelling for Cycling England shows that upping cycling levels by 20 percent in the 10 years up to 2015 could save £107 million in reducing premature deaths, £52m in NHS costs and £87m in fewer sick days.

Travel cheaper: travel cheaper

4 Get leaner

Sports psychologists have found that the body’s metabolic rate – the efficiency with which it burns calories and fat – is not only raised during a ride but for several hours after. “Even after cycling for 30 minutes you could be burning a higher amount of total calories for a few hours after you stop,” says Mark Simpson of Loughborough University.

And as you get fitter the benefits are more profound. One recent study showed that cyclists who incorporated fast intervals into their training burned three-and-a-half times more body fat than those who cycled constantly but at a slower pace.

Loads of people who want to lose weight think going out for a jog is the best way to start. But while running does burn fat well, it’s not kind to your body if you’re a little larger than you’d like to be. Think about it: two to three times your weight crashes through your body when your foot strikes the ground. If you weigh 16 stone, that’s a lot of force!

Instead, start on a bike – most of your weight is taken by the saddle so your skeleton and joints don’t take a battering. One of the most attractive advantages of cycling for fitness is that you can combine it with commuting, getting to work earlier and fresher after an invigorating ride. You’ll also be becoming fitter by the day without really trying, and feeling and looking younger. According to the National Forum for Coronary Heart Disease Foundation in the US, regular cyclists enjoy a fitness level equal to that of a person 10 years younger.

Get leaner: get leaner

5 Save the planet

It takes around five percent of the materials and energy used to make a car to manufacture a bike, and cycling produces zero pollution. Bikes are efficient machines too – you travel around three times as fast as walking for the same amount of energy and, taking into account the ‘fuel’ that you put in your ‘engine’, you can do the equivalent of 2,924 miles to the gallon. You have your weight ratio to thank for that: you’re about six times heavier than your bike but a car is roughly 20 times heavier than you.

With nearly a quarter of the UK’s CO2 emissions now coming from road transport, it’s no surprise that leaving your car at home is going to help pollution both locally and globally. Transport is on its way to overtaking industry as the major contributor to CO2 emissions in the UK. Vehicles give out about 70 per cent of air pollution in UK towns and cities, and 22 percent of the UK’s total CO2 emissions. Going by bike contributes nothing, and either walking or cycling much more for local journeys would reduce our dependence on oil.

If all commutes in England under five miles were completed by bike instead of car they would save a collective 44,000 tonnes of CO2 every week, the equivalent of heating 17,000 houses. Given that the average speed of rush hour traffic in London is 7mph and a reasonable average cycling speed is 13mph, that makes commuting by bike almost twice as fast as taking the car. Oh, and 20 bikes can be parked in one car space.

Save the planet: save the planet

Some inspiring numbers to get you on your bike

You don’t need us to tell you that getting on your bike is a good idea, you can do the maths for yourself. With the physical, financial and environmental benefits, you’ll soon find out cycling really does add up! The following figures relate to cycling in the UK:

  • 20 times less dangerous than not cycling
  • 97% chance of not getting rained on
  • Twice as fast as a car in traffic
  • 4 miles is the average cycle commute
  • £382 a year to boost the economy for every new cyclist
  • At current rates, 60% of the population will be obese by 2050
  • A bike takes 6.2 tonnes less carbon than a car to make
  • 10 bikes can be parked in the space it takes to park one car
  • A Zone 3 Oyster card commute in London costs £5.80 a day
  • Cycling in London has increased by 91% since 2003
  • A middle-aged cyclist is typically as fit as someone 10 years younger
  • 16 mile commute = 800 calories. That’s 4 bags of crisps or 12 fig rolls or 6 bananas or 6 cans of coke
  • 60% of car trips are shorter than 5 miles
 

Cada vez mais encontramos técnologia nas nossas bikes.

Fica a análise do desviador XTR 2011 ao pormenor.

Second to shifting, chain management is the most important job a rear derailleur has to perform. Today’s ultra-light long-travel trail bikes have us riding rougher trails, faster – all factors which collude to pop chains off both the cassette and chainrings. Enter Shimano’s new Shadow Plus design, which allows the sprung lower pulley cage to be ‘locked out’ below its parallelogram linkage, dramatically reducing chain movement.

Shadow Plus was unveiled at this year’s Sea Otter Classic on Shimano’s latest XTR M985 rear derailleur. At the launch, Matt Robertson, Shimano’s mountain bike product manager, made the bold claim that if you’re an aggressive trail rider, the new design will “change your life”. While we wouldn’t go that far, our initial ride impressions suggest that Shadow Plus will be a big improvement for riders who have problems with chain slap, suck and drop – so long as they have deep pockets.

Ride performance

We noticed three things straight out of the gate after our first couple of shifts with the new XTR derailleur: shifting is notably heavier than with previous XTR rear mechs, the action is incredibly precise at the business end, and the new design makes the drivetrain incredibly quiet. Chain slap is virtually non-existent on all but the hardest hits.

The lever requires a much harder push with your thumb than previous Shadow derailleurs, to the extent that we really felt the difference, in terms of tiredness, after a three-plus-hour ride. This extra effort is something any rider can, and will, adapt to should they see the benefit of the derailleur’s improved chain management.

The shadow plus derailleur features an on-off switch for the lower pulley cage's friction ratchet:

The Shadow Plus derailleur features an on-off switch for the lower pulley cage’s friction ratchet

The usefulness of this technology will definitely vary from rider to rider. It’s unlikely to appeal to cross-country racers, and it might not even be for every trail rider, as it’s slightly heavier and slightly more expensive than the standard XTR M980 rear mech. The litmus test is likely to be how much chain slap, suck and drop affects your riding.

If you’re constantly dropping chains or already have some sort of shift guide on your rig — like e*thirteen’s DRS or MRP’s LRP — then Shadow Plus may be just what you’re looking for. If not, you might prefer the lighter action of Shimano’s standard derailleurs.

For those trail riders who wish to use a triple ring crank the Shadow Plus derailleur will likely prove the best possible chain management option, if merely for the fact there are very few triple type guides.

For single-ring trail riders, the new XTR mech should offer better consistency than ultra-light top-only chain guides like e*thirteen’s XCX or MRP’s 1x. However, cost is likely to be a major stumbling block: at US$249.99, it would be cheaper to buy a standard XT Shadow rear mech and any of the chain guides listed above. Hopefully we can expect to see this technology trickle down to XT soon, especially given the second tier group’s trail intention.

The technology behind the concept

Inside the Shadow Plus derailleur is a spring-loaded one-way ratchet gear surrounded by a band-clamp. When the Shadow Plus switch is in the off position, the derailleur reacts like any other with a spring loaded lower pulley cage. With the switch in the ‘on’ position, however, the clamp tightens, engaging the ratchet.

The gear wants to ‘ratchet’ backwards freely, but it must pull against the band-clamp, which acts as a sort of clutch to prevent the pulley cage from moving forward; it can move forward but it takes a considerable amount of force. The end result is an almost fixed lower pulley cage, which prevents the chain from slapping the chainstay or bouncing off the front chainring.

A look inside at the friction mechanism; the switch is turned 'on' which tightens the band around the center ratchet:

A look inside at the friction mechanism; the switch is turned ‘on,’ which tightens the band around the central ratchet

The roller, in the foreground, tensions the system:

In the ‘off’ position, you can see the cam that tensions the band around the lower ratchet gear

The derailleur is meant to be ridden with the switch in the ‘on’ position all the time, but the ‘off’ setting allows shifting to be initially adjusted or fine-tuned and also makes it easier to remove the rear wheel. The XTR Shadow Plus rear mech will be available from June. UK pricing is still to be confirmed.

Manufacturers description

The newest addition to the XTR Dyna-Sys drivetrain is the RD-M985 Shadow Plus rear derailleur. The Shadow Plus feature provides a selectable pivot for the pulley cage that can use a heavier spring and increased pivot friction to counteract the forces of up and down chain momentum in rough terrain. The chain bouncing can often cause noise as the chain slaps the top and bottom of the chainstay, or even cause the chain to derail from the front ring in extreme circumstances. The new pivot when selected to the “ON” position dampens the cage and consequent chain movement for a nearly silent and stable riding experience. In the “OFF” position the derailleur will function like a standard Shadow rear derailleur and eases the installation and removal of the rear wheel by relaxing the spring tension on the cage.

 

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.

Tagged with:  

Por trilhos do Alentejo em Reguengos de Monsaraz

http://piranhasdoalqueva.blogspot.com/

Data: 2011-05-29

Por trilhos do Alentejo e tendo como cenário magnificas paisagens do maior lago artificial da europa, ai está um passeio BTT a não perder em Reguengos de Monsaraz no dia 29 de Maio.

Os percursos terão 50 e 30 km e as inscrições custam 15 euros, ou 10 euros sem almoço.

Este ano decidiu-se no percurso dos 50 Km um traçado de Andamento Livre (Competitivo) de cerca de 35 Km com partida no Monte do Barrocal e a linha de Meta em Reguengos de Monsaraz. Após completados os primeiros 15 Km que será efectuado em conjunto com os participantes do passeio de menor distância (+/-30 Km) será efectuada a partida para a Prova de Andamento Livre, que terá o percurso devidamente marcado e sinalizado, sendo cronometrado o tempo de cada participante.

Contribuição de tiago

 

Video Passeio em Sintra

On 2011-04-15, in Blog, by Dany

Vídeo com alguns colegas do trabalho pela Serra de Sintra,

Cliquem na imagem para começar o vídeo.

Passeio de BTT pela Serra de Sintra

 

Novidades Shimano XT 2012

On 2011-04-14, in Blog, by Tigas

Ficam as (muitas) novidades da Shimano para o XT 2012.

O BTT agradece esta relação preço/qualidade ;)

Shimano XT's crankarm and spider get some new styling for 2012

—–

Mountain bikers can look forward to lower prices, sharper looks and more braking power as Shimano roll-out upgrades to their second-tier Deore XT groupset to mark its 30th birthday. In line with tradition, the new XT will inherit many of the changes introduced to XTR last year, but despite the updated technology, Shimano say we can expect the price of the complete groupset to drop by around 10 percent.

Plenty more for XT

Versatility seems to have been the word written across the blackboard in big, bold letters at the XT development lab. The groupset will offer a dazzling array of options designed to address the requirements of cross-country, trail, all-mountain and ‘trekking’ riders alike. The chain and cassette are two of a very short list of components that have escaped redesign – and that’s only because they were updated last year when XT went 10-speed.

While Shimano continue to tout the benefits of a 3×10 setup, XT’s position as a staple for the cross-country market has been acknowledged with the introduction of a two-ring crankset, with a 38-26T option for trail riders and 40-28T for racers. Less shifts means less work for the left-hand shift lever, but rather than complicate things with multiple lever options, the new XT lever features a mode converter for easy adaptation between three- and two-ring setups.

XT brakes get the cooling fins debuted on xtr last season: xt brakes get the cooling fins debuted on xtr last season

Braking will get a big boost, with the Ice Tech technology unveiled on XTR last year being passed down to its sibling. XT will benefit from the same striking cooling fins and one-way bleed system, as well as new rotors with the same stainless steel/aluminium/stainless steel construction. All-in-all, Shimano claim a 25 percent increase in braking power as well as vastly improved heat dissipation.

The big S are also introducing dedicated XT-level ‘trail’ and ‘race’ wheelsets for 2012. The former has 21c tubeless-compatible anodised aluminium rims, with a 15mm E-thru hub up front and a choice of 12mm E-Thru or quick-release axle out back. The ‘race’ option has narrower 19c rims, with a quick-release rear hub and a choice of QR or E-Thru up front. All the wheels have cup-and-cone bearings, Center Lock disc mounts and 24 stainless steel spokes.

Shimano's top four brakesets now all feature one-way bleeding as standard: shimano's top four brakesets now all feature one-way bleeding as standard

The new groupset will be offered in either silver or black. The latter will provide a good match for the new XT pedals which, as with XTR, include an integrated cage trail option (PD-M785) as well as a slimmer race version (PD-M780). Both have a much bigger surface contact area than the current M770 for improved stability, along with a slimmer axle housing for improved performance in mud.

  • Crankset: 42-32-24T triple, 38-26T double or 40-28T double
  • Rear derailleur: Improved Shadow design
  • Front derailleur: Angled adjustment screws and clamp bolt for easier fitting and maintenance; direct mount option
  • Chain: New 10-speed HG-X directional
  • Cassette: 11-36T, 11-34T or 11-32T (CS-M771-10)
  • Shifters: Rapidfire Plus with Vivid indexing (as on XTR); Instant, Multi- and 2-Way Release; mode converter allows use with double and triple cranksets
  • Brake levers: Lightweight, with Servo-Wave technology, free stroke adjuster and tool-less reach adjuster;  one-way bleeding system; Ispec compatible
  • Brake callipers: Compact, with oversized 22mm ceramic pistons and one-way bleeding system
  • Brake rotors: Ice Tech technology (aluminium core embedded in stainless steel) for improved heat management; 160/180/203mm with Center Lock or six-bolt mount
  • Brake pads: Optional Ice Tech pads with aluminium cooling fins
  • Pedals: Lightweight cross-country (PD-M780, 343g/pair) and integrated cage trail (PD-M785, 408g/pr) versions

The new XT will be available from July, with pricing TBC.

Shimano were showing off this bike kitted out with a complete 2012 deore xt groupset on the opening day of this year's sea otter classic:

Trick new bits for ‘trekking’

Shimano have broadened XT’s appeal by developing a series of components and features aimed at commuters and leisure cyclists, or in their terminology, ‘trekking’ cyclists. Durability and practicality is the aim of the game here, with full-length outer casings, hub dynamos and an integrated chain guard for the front end of the 10-speed drivetrain.

The trekking group comes with a choice of V-brakes or Servo Wave disc brakes with three-finger levers. The discs don’t get the mountain bike brakes’ cooling fins but they do come with Ice Tech rotors (160 or 180mm, Center Lock or six-bolt). Shimano claim a 14 percent increase in stopping power over the current equivalent – a considerable improvement for those weighed down by panniers and racks.

Black or silver, trekking or non-trekking - there are a dizzying array of options available for xt users to choose from: black or silver, trekking or non-trekking - there are a dizzying array of options available for xt users to choose from

The Hollowtech II crankset will be available in two versions: FC-T781 (48-36-26T or 44-32-24T; chain case compatible) and FC-T780 (48-36-26T: not chain case compatible). Both feature an integrated chain guard. Out back, there’ll be a choice of 11-32T or 11-34T cassette.

Two new 6V-3.0W hub dynamos are available. DH-T785 is a disc brake version with Center Lock rotor mount, while DH-T780 has been designed for use with V-brakes. Both have an aluminium coil and axle, bringing weight down to a claimed 483g.

A 'trekking' variant of xt will also be available: a 'trekking' variant of xt will also be available

There’s a new trekking pedal to go with the two XT mountain bike options – the double-sided (SPD binding on one side, flat on the other) PD-T780. Claimed weight is 392 g/pair, including integrated reflector. Like its mountain bike stablemate, the groupset will come in a choice of black or silver. Availability is slated for August 2011.

XTR Shadow Plus rear derailleur

At the launch of the new XT, Shimano also unveiled a new XTR M985 Shadow Plus rear mech. Designed to complement the ‘trail’ rather than ‘race’ variant of the group, it has an on/off switch on its cage which can be used to add more spring tension and activate a ‘friction stabilizer’.

The idea is that you switch this on to stop your chain bouncing when riding over rough terrain – preventing it from derailing or damaging your drive-side chainstay, and also cutting noise – but flick it off at the end of your ride to reduce the spring tension and make it easier to remove your rear wheel. The new mech will be available from June. There’s no word yet on pricing.

Shimano xtr rd-m985-sgs rear derailleur:

 

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 ;)

—-

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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BTTecos, Trilhos e Courelas 2011

On 2011-04-12, in Blog, by Paulo986

Boa tarde pessoal,

Eu e o meu irmão fomos, por mais um ano, a Vendas Novas, participar na famosa maratona de Vendas Novas (trilhos e courelas)

As expectativas eram um pouco altas, pois tinha-mos treinado bem e sentia-me em forma!

Também ia ser o baptismo da minha Look em maratonas!

Chegamos um pouco atrasados e por isso o lugar na partida não foi o melhor!

O arranque foi forte e o andamento também, num percurso muito rolante, com muita areia nos primeiros km’s, sem nenhum alcatrão =D, mas também sem nenhum single-track e com poucas subidas!

Deixo aqui uma análise à vertente “Trilho Médio” (55km)

Secretariado: 5/5 – Rápido, eficiente, sem nada a apontar!
Partida: 4/5 – cerca de 12min atrasada, mas sem grandes percalços!
Percurso: 4/5 – Muito rolante, muita areia nos km’s iniciais, e a partir sempre a esgalhar até ao final, gostei, mas um single ou outro não fazia mal a ninguém, o que gostei bastante foi de ter havido muito pouco alcatrão!!
Marcações: 5/5 – Impecável, acho que quem fosse com o mínimo de atenção não se perdia!
Abastecimentos: -/5 – não parei, não posso comentar o que havia, agora aqui acho que a organização falhou um pouco, muita distância entre o 1º e o 2º abastecimento e muito pouca distância entre o 2º e o 3º e na meta podiam ter disponibilizado algo para o pessoal trincar, pois só havia água!
Controlos: 0/5 – Controlo zero tudo normal e não houve mais nenhum controlo até ao final, é lamentável esta situação, muito má mesmo… pouca gente da organização durante o percurso!
Chegada: 3/5 – nada a apontar à chegada, só o reparo que dei anteriormente, disponibilizar alguma coisa para o pessoal repor um pouco de forças!
Lavagem de bikes: 5/5 – muitas mangueiras com alguma pressão!

Em relação às classificações e como disse anteriormente esperava melhor, mas pelo que me apercebi o pessoal este ano está todo fortíssimo!

1º – José Melitão – 2:01:56

2º – Pedro Fernandes – 2:06:17

…..

39º Gonçalo Crispim – 2:24:52

….

44º Paulo Crispim – 2:25:54

Deixo aqui algumas fotos:

 

http://www.oestebike.com

Data: 2011-05-21

Com a organização de Marco Chagas e Justino Curto, o Oeste Bike contempla uma Feira de Bicicletas no Parque de Exposições Expotorres (abre dia 20 de Maio), uma Maratona de BTT (no dia 21) com 15, 50 e 90 km de alternativa e um Passeio de Cicloturismo no dia 22.

A Feira aberta ao público e com a presença de algumas das principais marcas existentes no mercado nacional terá cerca de 1400m2 de espaço interior e, tal como o Festival Bike de Santarém, incluirá actividades paralelas, incluindo demonstrações e workshops. Esta decorrerá nos três dias do evento (20 a 22 de Maio) e um destaque especial vai para o Dia da Família, em que haverá um serviço especial de babysitting para crianças dos 2 aos 6 anos de idade que incluirá jogos e actividades monitorizadas.

A BIKE Magazine é a revista oficial deste evento, consulta o site www.oestebike.com para mais informações.

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