Porsche bike

On 2011-03-31, in Blog, by Tiago

Porsche Bike FS Evolution

 

Video BTTecos.com no Monsanto

On 2011-03-31, in Blog, by Dany

Olá amigos,

Fica aqui o primeiro video que fizemos para experimentar a câmara.

 

Pois é, estes meninos não brincam em serviço!

3ª etapa = 3ª vitória de Sauser e Stander … julgo que este ano não dão hipóteses ;)

The leading bunch crosses a dam wall in the witzenberg valley during stage 2:

 

Avid Elixir R – Review

On 2011-03-30, in Blog, by Tigas

Uma solução decompromisso para quem não quer gastar muito dinheiro nuns travões mas quer ter um bom poder de travagem.

Avid Elixir R

Unlike the cheapest, supplied-on-bikes Elixir models, the R gets the same TaperBore inline reservoir design as the top-end brakes. Crucially, there’s no rotating bite point adjuster at the far end, which removes most of the bleeding and reliability problems of the family.

The flip-flop design makes it easy to swap over, and it gets the same Matchmaker shifter clamp sharing options as more expensive brakes too. The lever is reach adjustable and has a unique dislocation feature to reduce the chances of crash damage. There is potential for misalignment when setting up the cup-and-cone brake mount but the pads are easy to remove and replace.

While it’s not outstanding on the dyno, the unique lever sweep geometry gives the Elixir R a great feel under your fingers on the trail. There’s loads of progressive, predictable modulation and a 185mm rotor is enough for all but the most aggressive riders.

Ao contrário o mais barato, fornecida sobre modelos, motos Elixir, a R recebe o mesmo design TaperBore reservatório embutido, como os travões topo de gama. Fundamentalmente, não há ajuste de ponto de giro mordida no outro extremo, o que remove a maioria dos problemas de sangramento ea confiabilidade da família.

O design flip-flop faz com que seja mais fácil trocar, e recebe o mesmo Matchmaker opções shifter braçadeira partilha de freios mais caro também. A alavanca é chegar ajustável e tem uma característica única deslocação para reduzir as chances de danos acidente. Há potencial para o desalinhamento, ao estabelecer o freio-copo e cone-monte, mas as almofadas são fáceis de remover e substituir.

Embora não seja excepcional no dyno, a geometria de varredura única alavanca dá a R Elixir uma grande sensação em seus dedos sobre a pista. Há montes de modulação progressiva, previsível e um rotor de 185 milímetros é o suficiente para todos, mas os pilotos mais agressivos.

 

BTT – Cape Epic já roda…

On 2011-03-29, in Blog, by Tigas

Pois é, o Cape Epic já roda e com a dupla Sauser e Standar a atacar desde o ínicio.

Kevin evans prior to crashing out: kevin evans prior to crashing out

Fica o video.

 

Novos Avid Elixir 9 2012

On 2011-03-25, in Blog, by Tigas

Chegam as primeiras reviews aos novíssimos Avid Elixir 9 de 2012 (segundo a marca).

Estes novos travões vêm substituir os Elixir CR que tenho na minha bicla e até agora sem problemas.

Fica o review.

Avid Elixir 9 review

The Elixir 9 is all-new for 2011 (it’s officially a 2012 model year product) and uses Avid’s reworked Taperbore design. While we got our hands on it too late to test it on the dyno and include it in ourlatest disc brake super-test, we’ve been impressed by its performance on the trails.

When Avid talk about their brakes they mention something called ‘deep stroke modulation’. Our first experience with this came while riding a 180-degree switchback on ice and snow, where the subtle power control allowed us to micro-manage braking on the very verge of skidding. Puckered and skittering across the ice, we managed to keep traction. With any less modulation, we’d have been on our butts.

That scenario played out a fortnight into our four-week test of the new Elixir 9. Our first experience of the brake was at its launch in Santa Cruz, California in February, where we rode steep and muddy ‘gravity’ trails to gain a first impression. During those two days we just grazed the tip of the product, but the inclement weather produced some interesting results.

In Santa Cruz it rained. Actually it poured, but we rode anyway on steep trails that put us in a perfect position to really test the brakes. Why? We used them a lot — more than we should have — because we were riding trails, blind, that pushed us and the bikes hard, toward the upper limits of our riding skills. So we dragged the brakes, and they heated up, but they didn’t fade; score one for Avid.

The caliper sports a new forging:

We found the sintered pads to wear quickly in wet conditions

Something we did notice, however, was pad wear. After a half dozen rides — in atrocious conditions, mind you — the pads appeared to be half gone; score one against Avid. This says something about the pads’ durability, which we’ll elaborate on after longer-term testing, but also for the increased volume and air penetrability of the revised Taperbore system. Even though the worn pads required the pistons to push further out, the brakes maintained consistent feel and performance. We’re not sure Avid’s older brakes would have coped as well.

Home turf testing

After returning from the launch, we immediately mounted the Elixir 9s to our Santa Cruz Butcher test mule. Actual weights are 392g for the front brake (with 180mm rotor and hardware) and 360g for the rear (160mm rotor and hardware). We rode them predominantly on our two burliest low-elevation wintertime test tracks — trails that put 150mm of travel to legitimate use — with good results.

Since we know our home trails better than those in Santa Cruz, speeds were higher and braking was both harder and more professional — meaning we weren’t dragging them like a noob. The result was good, usable power and modulation. The brakes are middle-of-the-road when it comes to pure power, yet above average in terms of a mix of power and modulation, which makes them very usable.

The new 180mm rotor weighs 126g and requires a spacer that weighs just 13g:

The 180mm rotor bracket weighs just 13g on our scale

We haven’t noticed any loss of power due to the switch to a 180mm front rotor, even in a back-to-back comparison with an older CR model with a 185mm rotor; in fact it seems slightly better. Modulation is certainly better than CR, after a break-in that lasted a couple of rides; initially the brakes could be described as grabby.

We’ve set and reset the reach adjustment and fine-tuned the lever’s feel and (actuated) placement using the detented pad contact adjustments with good results. We’ve also bled the brakes once after shortening the lines, which was an uneventful task and produced seemingly solid results. Lever feel isn’t super-firm — we’d like it slightly firmer — but we haven’t experienced any fade or inconsistency in feel, despite riding them hard and hanging the bike for storage.

Overall, Elixir 9 seems to be a positive evolution of Avid’s TaperBore concept. It’s a solid brake with a very good ratio of power to modulation and, so far, more consistent than the CR model it replaces. While the Elixir 9 is a 2012 model product, it’s due to hit shops in the US next month. UK price and availability is still to be confirmed.


 

BTT – Nutrição

On 2011-03-24, in Blog, by Tigas

Mais um excelente artigo sobre nutrição.

Desta vez como os Antioxidantes podem ajudar o treino BTT.

Antioxidants seem to be everywhere these days. They’re the ‘in’ thing in nutrition and if you believe the hype they can cure every disease, help you go faster and even live forever. Let’s take a look at the science behind the hype and see if there’s any evidence that as a cyclist you should be including these in your diet.

Antioxidants act by counteracting something called oxidative stress, which causes damage to the body. During day-to-day living your body produces things called reactive oxygen species that attack the body. Think of it as oxygen on a rampage around your body. You naturally produce antioxidants to protect your body from this attack, so think of this as your body’s police force. However, you need to get extra antioxidants from your diet to support this police force – think of these as the riot police.

There’s a huge body of research looking into the effect of antioxidant intake on health. With the advent of processed food a lot of the antioxidant capacity of our foods has been removed. It’s quite clear from the research that antioxidants can help prevent diseases such as cardiovascular disease, diabetes and cancer and help you live a long life.

The health benefits of a diet high in antioxidants is clear, but the performance benefits are less so. We know that exercise, particularly hard training, increases oxidative stress, but we also know that the body responds to this by increasing the size of its police force. However, when you train hard, the body can’t increase its natural antioxidants enough, so you need to make sure the riot police are ready to go.

Stress reduction

A recent study from the University of Newcastle in Australia looked at restricting fruit and vegetable intake on exercise performance and how the body responded to the training. Fruit and vegetables are probably the most important source of antioxidants in the body. The study showed decreasing your weekly fruit and veg intake from five a day to one a day caused performance to be impaired by two percent and the stress of the exercise was greatly increased. So there is a performance benefit to a diet high in antioxidants.

As we’ve seen, fruit and vegetables are the most common food source of antioxidants. They contain nutrients such as vitamin C and E as well as other antioxidant compounds. Nuts and seeds as well as wholegrains (as opposed to refined grains like white bread and pasta) also contain high amounts of antioxidants.

There are also many supplements on the market that may help improve your antioxidant capacity, although these aren’t proven by science. The antioxidant system is very complicated and food is always going to be more effective, as nutrients work in interaction. A good example is a recent study showing high doses of vitamin C actually inhibited the adaptation from training.

What to eat

So how can you increase your antioxidant capacity? Sources of antioxidants can be found in all kinds of common foods, so make sure you get enough:

The good

You know these foods are good for you, so make sure you:

  • Eat five portions of fruit per day
  • Eat five portions of veg per day
  • Steam your vegetables rather than boil them

The bad

You might try to avoid these, but in moderation they help provide powerful antioxidants:

  • Red wine: a glass a day is plenty
  • Dark chocolate: stick to two or three small squares a day
  • Espresso

The ugly

You might think these things wouldn’t make much difference, but they do:

  • Add herbs to your food
  • Add extra virgin olive oil and balsamic vinegar to meals
  • Look for foods which are dark in colour such as berries
 

Cá está, o conceito de bicicleta BTT electrica está a tomar formas mais … normais ;)

Gates, Bosch, and NuVinci combine to make pedal-assist e-bike concept, not Voltron

There’s those who want electric bikes that’ll hurtle you down the road at 40mph at the twist of the throttle, and there’s those who believe pedaling to be enjoyable enough, but would like a less strenuous bicycling experience. If you find yourself a member of column B, listen up, because Gates, NuVinci, andBosch have created an e-bike concept that’ll satisfy your two-wheeled transportation needs. Gates supplied its Carbon electric belt drive, NuVinci brought its N360 infinitely variable planetary hub, and Bosch threw in a battery and control system to make a bicycle beauty. The power train is set up to give riders pedal-assist with four settings that go from Lance to lazy, depending on your mood. At an estimated cost of €2,600 – €3,200 ($3,680 – $4,530), you’ll need a bank account comparable to the seven-time champion of Le Tour should an OEM pick up the design.

 

Cá está mais um artigo interessante de como afinar a bike por forma a obter um melhor rendimento.

Ficam as dicas!

Getting a bike to fit you perfectly is something you need to work at. We know riders who’ve ridden for years on what they thought was their perfect bike, with perfect reach, perfect saddle height, perfect handlebar shape, a perfectly set up fork and perfectly inflated tyres.

Then circumstances put a fly in the ointment and they discover that a basic change, perhaps even a few basic changes, to that setup seems to make them ride better. It’ll often be something as simple as a different handlebar sweep, different tyre pressures or more suspension fork sag. It’s often minor details of bike setup that change the way you ride, and feel about, your bike.

Tweak your ride setup from time to time, then give yourself a few rides to decide whether you like it or not. There are some things that feel wrong when you first change them, but feel right after a few rides. In the following article we’ll lay down the basic guidelines of bike fit, together with variations  to consider and the reasoning behind them. Don’t think of bike fit and setup as something that’s carved in stone. Use our guidelines as a starting point, then go out and experiment…

Sitting comfortably?

This images below show the key areas that should be adjusted for you to achieve optimum bike fit. The first image shows the incorrect position, while the second image shows how the bike components should be positioned. Good bike position results in relaxed shoulders and slightly bent elbows

Wrong: wrong

Right:

  • Arms: Good bike position results in relaxed shoulders and slightly bent elbows.
  • Saddle: Correct saddle position is essential for balance, control and pedalling efficiency.
  • Knees: Having very slightly bent knees at the bottom of each pedal stroke is perfect.
  • Frame: Getting the correct frame size is essential, but it’s only a starting point for perfect bike setup.
  • Shifters and brake levers: Don’t just leave them in one position. Experiment with setting them further in on the bars or tilting them.

Although everyone is different – some folks may have longer legs but a shorter torso, while others may have long arms but short legs – starting with the correct-sized frame allows you to further tune the position using stem, bar, seatpost and saddle tweaks.

Frame sizing

Manufacturers’ listed frame sizes can be confusing. The traditional method is to list the seat tube length, but even that varies because some are measured to the top of the seat tube and some to the middle of where the top tube joins the seat tube. Many manufacturers simply list their bikes as S, M and L, perhaps with XS or XL at either end.

Either way, the measurement that matters more is top tube length. Together with seat position, stem length and handlebar position, top tube length dictates the comfort and efficiency of your body on the bike. To confuse matters further, the aspect of top tube length that matters is not the top tube itself, which often slopes, but a horizontal line from the middle top of the head tube to the middle of the seatpost.

So, where do you start to find out what size frame you need? Like so many other things on a mountain bike, there’s no one perfect solution, as within sensible limits you can adjust your saddle, stem and handlebar to help a slightly imperfect fit feel fine. Bear in mind that road, cyclo-cross and hybrid bike sizes tend to be 3-4in bigger for the same rider height. We mention this because a lot of riders are confused by it when flicking through bike listings.

Here are some guidelines:

  • XS bike (13-14in): Generally for riders between 5ft and 5ft 4in
  • S (14-16in): Generally for riders between 5ft 4in and 5ft 7in
  • M (16-18in): Generally for riders between 5ft 7in and 5ft 10in
  • L (18-20in): Generally for riders between 5ft 10in and 6ft 1in
  • XL (20-22in): Generally for riders over 6ft 1in

What really matters is how the bike feels when you sit on it and ride. The first thing you need to do, in the shop or on a demo ride, is set the saddle at the right height.

Carefully padded slimline saddles can be comfier on longer rides than heavily padded ones: carefully padded slimline saddles can be comfier on longer rides than heavily padded ones

Saddle height

A rough approximation of saddle height for efficient pedalling is your trouser leg measurement plus 5in from the centre top of the saddle to the centre top of the pedal. To work it out more accurately, with comfort and efficiency in mind, sit squarely on your saddle with the cranks in a straight up/straight down position. The saddle is at the right height when your heel just touches the top of the lower pedal with your leg straight; your crank should be right at the bottom of its stroke.

If you have to tilt to one side on the saddle to achieve this position then the saddle is too high. Place your foot on the pedal in the ready-to-pedal position. If your leg was straight with your heel on the pedal it should be slightly bent at the knee in a pedalling position. You should never feel as if you’re being forced to rock your hips from side to side on the saddle while pedalling.

You may need to make adjustments to this position according to confidence and comfort preferences, and depending on what shoes you wear. And keep in mind that this is all based on efficient pedalling for cross-country trail riding. Many riders will choose to set their saddles lower for difficult descents, hence the growing popularity of dropper seatposts for big terrain riding.

Saddle position

As a rule, start with your saddle as level as possible on the top. This is an efficient cross-country position but some riders will prefer a slightly tipped back saddle for tricks, stunts and/or steep downhill work, and a few who prefer the nose of the saddle slightly tipped down for climbing or a more forward-biased ride posture. But dead flat is right for most riders.

tilting the saddle back can have benefits for downhill, forward can help on climbs : tilting the saddle back can have benefits for downhill, forward can help on climbs

Saddle rails have a lot of fore/aft slide adjustment, and not all seatposts are created equal. Some have set-back clamps, others have clamps in line with the top of the post. This has a bearing on the position you’re trying to achieve with your saddle. A saddle set too far back can make the bike feel back-heavy, possibly even too light at the front to achieve proper suspension fork compression. A saddle set too far forward can cramp your ride position and make you feel as though you’re putting too much body weight on the front of the bike.

In theory, if a bike has exactly the right reach for you and the fork is set up properly, you’ll probably end up with the saddle set dead centre on its rails. If you’ve got long arms for your height you may end up with the saddle set well back: short arms and you’ll be looking at inline seatposts and your saddle forward. You can use stem length and handlebar position to fine-tune the way you sit over the bike too.

We’ve ridden a lot of bikes and discovered a few unusual aspects of bike setup that can help explain why a bike feels wrong for no obvious reason. One relates to saddle position. With your saddle at ‘perfect’ height, drop a plumb line from the centre of your saddle clamp to your frame’s chainstays. With everything set up for general trail riding, the plumb line should intercept the chainstays almost exactly halfway between the bottom bracket axle centre and wheel axle centre. If it’s further back you’re probably sat too far back. Put your saddle further forward for better balance, and to get the best out of your suspension forks.

Handlebar reach

If you have access to different stem lengths and different shaped handlebars, experiment with different ride positions, adjusting your saddle accordingly. Arm, leg and torso length will vary between riders of the same height and body weight distribution can have a major bearing on setup. A rider with a big belly will demand a different bike setup to a rider with a well distributed muscle mass or a heavy head – strange but true.

A guideline for saddle to handlebar reach is to put the tip of your elbow on the nose of the saddle and see how far your longest finger reaches along the stem; forearm length is generally a good indicator of full arm and torso length. Most riders looking for a fast and efficient trail riding posture will discover that their longest finger reaches to almost exactly halfway between the steerer top and the handlebar centre.

You can fine-tune ride feel from that point by adjusting your seat position, stem length and height, and handlebar type. Some handlebars have a more generous backsweep than others, and you can turn bars in the stem to tune your hold position/wrist angle. We know riders who like their bars straight and others who find a 25-degree backsweep their ideal solution. Keep that elbow tip to finger tip measurement in mind when working out whether a test bike is the right size for you.

Tip of the elbow on tip of the saddle to longest fi nger half way along the stem is the typically, perfect xc trail bike reach:

Handlebar height

How high you have your bars is a function of steerer height (and the amount of adjustment washers on it), stem height and rise, and handlebar rise. Some riders feel relaxed with their bars at roughly saddle height, others (particularly cross-country racers) have them way below saddle height to achieve a flat backed streamline posture on the bike.

Relative beginners might feel at ease with the bars set higher than the saddle. Bear in mind that you need enough body heft tipped towards the front of the bike to compress your suspension fork when you’re riding rough terrain. This becomes harder to achieve if your saddle is too low or your bars too high.

Hand positioning try different grips and different bar angles/backsweeps to fi nd your ideal  hand position:

Control positions

Brake levers and gear shifters can be put in different positions on the bar. On most brakes you can adjust lever reach too, and on some you can adjust the point of contact where the brakes compress the pads. We know riders who put up with their thumbs rubbing on their gear shifters for years before realising that setting them half an inch further inboard on the bars solves the problem without making them harder to use.

Bar width can be trimmed too: cutting an inch off either end of a 27in handlebar might make a difference to your ride comfort. Swivelling bars a few degrees back or forth in the stem can also make a difference. Don’t be afraid to try something different, but try it for a few rides in order to find the pros and cons of a new setup.

Shift/brake levers don’t have to be up against the grips. you can have them wherever you want them on the bars:

Material benefits

The materials that your bike’s components are made from can have some bearing on setup and comfort. Materials, and the way they’re used, have the most effect at the major contact points (with the rider and the ground). We’re talking about your tyres, your grips, your saddle and your pedals.

Tyres: Tyre compounds, as well as pressures, will affect the way a bike feels on the trail. Cleverly treaded dual compound tyres with a high tpi (threads per inch) carcass construction will generally deform more over rough terrain, and so grip better, without any increase in rolling resistance. Cheaply made tyres tend to grip less and are more prone to losing traction when under pressure, especially in wet conditions.

Grips: Dual compound handlebar grips, or grips made from soft foam, might not be as hardwearing as others but they’re far more comfy, absorbing vibration and making you feel more at ease on the bike on rough terrain.

Saddle: The right sort of surface material and the right sort of padding on a saddle is obviously going to make a huge difference to the way you feel about your bike. As a rule, you should be able to move easily on the surface of a saddle; fancy embroidered graphics aren’t always conducive to this. And don’t assume that more padding is always better. Slimline saddles with minimal padding in just the right places are often more comfy than big bouncy affairs, which will often chafe after a while.

Pedals: The efficiency of your pedal/shoe interface has an impact on how you ride. Stiff soled shoes with inset cleats fixed to clipless pedals will make you a more efficient ‘full circles’ pedaller. But read instructions carefully when it comes to cleat position because poorly positioned cleats can cause problems, especially with knees. Most riders start with their cleats set dead centre in the shoe recess, but that doesn’t feel right for everyone, and some cleats/pedals offer more free float movement than others.

Comfort and control variations

Your tyres, suspension fork and rear shock effectively provide an adjustable cushion between your bike and the ground. Setting them up properly is crucial to your overall control and comfort. Big volume tyres can be run at lower pressures than small volume ones, and big volume tyres with a low knob profile will often roll just as fast as, and offer more comfort and control than, skinny tyres.

A good tyre pressure starting point for average weight riders on typical 2.1in tyres is about 35psi. Careful or lighter riders will often run under 30psi, especially on tubeless tyres where there’s no tube to pinch puncture. Heavier, clumsier or harder-hitting riders might prefer 40psi+.

Fork and shock pressures will vary according to make and model, but aim for between a third and a quarter of the available travel as initial sag when you sit on the bike. Also, take some time to learn about your compression and rebound damping controls.

Setting the right fork and shock pressure is crucial:

Wrong fit ailments

Aches and pains can be caused by aspects of bike setup, but also by other things, so don’t take this list as gospel; it’s a rough guide. See your doctor if something is really hurting, especially if it continues to hurt after riding and it’s not solved by the adjustments mentioned here. Be aware that a lot of your aches and pains on a bike are simply caused by insufficient muscle support. In other words, you may just need to ride more and do some core muscle training to work things out.

Here are some common ailments and their causes:

Knees: Knee pain when riding can be caused by your saddle being too high or too low, or your shoe cleats being poorly adjusted. Some riders find that a pedal/cleat system with more free float gets rid of knee pain.

Back: Back pain during/after riding will often be related to poor core muscle support so there may not be a quick and easy setup fix. But try changing the position of your handlebars and/or your reach from the saddle to the bars. We know a lot of riders who’ve solved lower back pain simply by putting the stem up or down by half an inch, or getting a handlebar with more backsweep.

Shoulders/arms/neck: We’re putting these three together because it’s often similar aspects of set-up that cause aches and pains in these areas, namely too much stress being placed on these bits of your body. This may be caused by being sat too far forward on the bike but it can also be down to sitting too far back, making you curl your shoulders and preventing you holding the bar properly. Experiment with stem height and saddle-to-bar reach. Try different bar shapes: a lot of riders find that more backsweep or upsweep on a bar will make them feel far more comfortable. Also, try anatomically shaped grips, which support your hands better.

Hips: A lot of hip problems among cyclists are caused by the saddle being either too high, too low, tipped too far back or forward or not offering the right sort of padded support.

 

BTT Alte (2011-04-30)

On 2011-03-20, in Provas e passeios, by admin

BTT Maratona – XIII edição

http://btt.epalte.pt/in%C3%ADcio.aspx

Data: 2011-04-30

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