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16

Carbon fiber is stronger, and far less susceptible to fatigue than any other frame material on the market. It can be engineered to have the strength of titanium, the ride quality of steel, and the stiff and powerful performance of aluminum at the same time. I have only broken 2 frames in my life. Both were aluminum, ridden far beyond the fatigue life of ...


13

The seat tube is split because it has rear suspension - the rear of the bike rotates around a pivot located just in front of the bottom bracket. Several early full-suspension bikes used a similar design for the rear pivot; this design was then knocked off by the lower-end manufacturers looking to cash in on the popularity of mountain bikes. It's extremely ...


12

Watch the Tour de France...you'd be hard pressed to find a bike that is not carbon. Yes pros do get multiple steeds, but remember riding is their full time job. When was the last time one of us put 30-50 hours on a bike in a given week, never mind for 6-8 months! Now think about the wattage these guys put out and hopefully you are getting the idea...that ...


10

This would never work due to fact that no force would be transmitted to the rear wheel until the derailleur cage was at maximum extension. The derailleur has to be below the chainstay to allow it to take up the slack in the chain. I suppose you could split the derailleur into to parts, one to keep the chain tension and the other to change gears, but that ...


10

The derailleur needs to guide the chain into the sprocket - which means it goes on the bottom. The tension pulley needs to go on the slack side of the chain - which again means it goes on the bottom (the top side of the chain loop has the drive tension). If the drive train was reversed, you could do it. Put the drive wheel in front and steer with your butt ...


10

I think you need to separate operator error from optimal mechanical functioning. Mechanical advantage By your own anecdotal evidence you have demonstrated how powerful front brakes can be. In short we have front brakes because they are the most powerful brake. When a bike (or any vehicle) decelerates weight is shifted to the front wheel. Because ...


9

Well, from an engineering standpoint, no. It increases complexity, cost and weight. Those might be a deal breaker for the commuters who would likely use them. From a practical standpoint, maybe. @NL_Derek; you could be the first to test one! In conjunction with other folding components (frame like a Dahon & pedals), it may suit the users need, imagine ...


8

There are more factors than just the front brake that contribute to the flipping accident. I myself got into the accident once. It happens so fast that you never have time to lean your body backwards and provide more tractions for the rear wheel like other have stated. I should list some of the factors that contribute to the 'flipping'-style accidents: ...


7

So what do we need front brakes for? We need them for maximum braking efficiency and better control of the bike. Your question is flawed in the sense that it only has anecdotes from unskilled riders. Let's see some similar examples of equipment misuse: why do we have a rear brakes? They are not efficient and last time a friend of mine used it, the ...


7

The main advantage is aerodynamics, but it should also be cheaper, lighter and stronger than a two-piece combination. Aside from the shaping, the fibres will run continuously through both "parts" so there's extra strength from that and there are also no stress risers at the joins making them stronger again. In practice the strength and weight are a ...


6

The biggest factor in bike stopping distance is the mass transfer towards the front of the vehicle when braking. On an upright bicycle, the limiting factor in how hard you can brake is the point at which the front wheel goes from slowing you to simply throwing you over the handlebars. As you brake, your center of mass shifts forward, lifting the rear wheel. ...


6

We have front brakes in order to stop. In an emergency stop there is hardly any weight on the rear tire, and the rear wheel has very little traction. In each of these cases, the bike would not have stopped where it did, and there are certainly situations where rolling further would be more dangerous. There is a proper technique which is get back and low, ...


5

There are 2 versions of derailleurs which come with extra large pulleys. The first, which is what is being discussed here, are the low end mega-range compatible derailleurs. A mega-range freewheel has one distinct characteristic which requires compatible derailleurs to have very large cogs. As seen in the image below, there is a large tooth count ...


4

The only real advantage to a compact geometry road bike is for the manufacturers. Since standover- which is the distance from the top tube to your crotch when you straddle the bike with your feet on the ground- is increased, one size of frame will fit a wider height range of people and therefore the manufacturer does not have to make as many different frame ...


4

First, one small point. The two pictures show different types of extensions, not bars. Bars are still what the extensions attach to (Commonly called either aerobars or bullhorns). Extensions come in various types, including (but not necessarily limited to) S bend, F bend, straight, skip tip. Each have their advantages and disadvantages. Most wind tunnel ...


4

From my understanding, carbon fiber is extremely strong within its designed load parameters. That means the directionality of the load, the amount of load, etc. It is only when one goes outside this load design that you start to see failures (other than manufacturing flaws, but that could happen on any bike). For example, clamping a carbon fiber ...


4

The two are not directly related. On a conventional diamond frame the downtube angle is dependent on the length of the top tube and seat tube, and, of course, the seat tube angle. The length of the seat stay is dependent on the seat tube length and angle, and the length of the chain stay. Obviously, the two "share" the seat tube length and angle (which is ...


4

Actually there is one such solution from Campagnolo which did not really stick: The general idea was to skip tensor altogether, and recompense change in chain length (distance it travels) by moving sprocket (whole wheel) back and forward. The main disadvantage of such approach was reduced number of speeds you can have in our bike; mainly by disallowing ...


4

One problem is that the design would not be appropriate for technical riding requiring speed. Getting behind the seat to push against the pedals would put you out over nothing, instead of out over the back wheel. The design would be less stable because of that and consequently unsuitable for technical riding. The puts it out for mountain styles of riding. ...


4

Running through a quick list of "engineering considerations" that I've just made up: costThese will cost more to design, test, manufacture and assemble at point of sale than conventional handlebars. They're more complex, so I can't see any way around the extra cost. The benefit seems to be slim outside of some fairly specialised scanarios, and for many of ...


3

Wheel locks are an implementation of this idea. They simply prevent the rear wheel from turning, which is effectively the same thing. Again, any thief with large enough bolt cutters will be able to effectively sidestep the problem without hassle. But worse than that, the odds of your bike being stolen while being immobilized like this are still orders of ...


3

Carbon fiber often stands up to higher stresses than comparable aluminum or steel frames. You really have nothing to be worried about as long as you are buying from a reputable manufacturer. Check out this video for more info: Santa Cruz tests carbon vs aluminum frames You'll notice that aluminum fails under much less stress than carbon does in almost ...


3

Here is an example of high-end carbon fiber frame with similar geometry = Trek Y Foil. It proved to be unsuccesful design, but low-end bicycle manufacturers copied it anyway (also using cheaper materials and simplified design).


3

There have been a few "serious" bikes made with this design; Trek produced a few years ago. However, it proved to be a poor design as it puts the pivots in the wrong places. I took one of those cheesy Y-frames and used it as the basis for my home-built recumbent...It actually worked pretty well for that.


3

There are a few designs that could involve rear wheel pedalling, and none of them seems to be particularly advantageous when compared to today's standards. Here are two major ideas: The design which is shown in the picture i.e. saddle somewhere around rear wheel axle - when using a standard frame your position will be very hunched. Yes, this may give an ...


3

Aside from touring specific braze-ons (rackss, fenders, spokes, pump, etc), the short answer is that adventure touring bikes are going to be more well suited as an all around machine where as an MTB has a narrower performance mark. The long answer is frame geometry. Briefly looking at the geometry of some of the bikes you listed shows the Kona having ...



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