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36

IS mounts (also frequently called IS tabs, disc tabs, etc) are unthreaded eyelets 51mm apart that bolts run through parallel with the hub axle. In almost all cases the brake caliper is then bolted to an adapter that has one set of threads for the IS mounts and another 74mm apart for the caliper. (There are a very few caliper models that omit the adapter, ...


29

Having an overlap between the ratio ranges available with each chainring means you don't have to use your front derailleur as much. Based on your understanding and expectations of the terrain and conditions ahead, you choose a chainring which gives you access to a useful set of harder and easier ratios. The cassette ratios are spaced to achieve a vaguely ...


22

The "asymmetric wheel" terminology is a little misleading. This particular wheel has an asymmetric rim. Any bike with a rear derailer setup will have an asymmetric rear wheel, because the gears take up space. The usual way to handle this is that the spokes on the gear side have less of an angle (closer to vertical) than on the non-gear side. (That is, they ...


21

The ratios aren't spaced out consistently Actually, if you look at your diagram and exclude the smallest and largest cog on the cassette, the gears are more or less evenly spaced. What unevenness there is is an artefact of the requirement for whole-number ratios. Sure, replacing the 15t cog with a 14.5t cog would give better spacing between the 17t and 13t ...


15

Standard Pawl and Ratchet Design This design is by far the most common on bicycle freehubs, and as such the least expensive to employ. Mechanism In it's simplest form, this design consists of a surface that is toothed and a pawl (which is a lever that engages the toothed surface and only allows movement in one direction). In a bicycle this design is ...


13

Interesting question and way of looking at it. Here's my take: those in the bike world who would seem most qualified to design scientifically optimal frames, which involves both mastery of all the advanced fabrication techniques and materials that are now available and the motivation to empirically figure out the handling and ride feel elements that can be ...


12

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 ...


12

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 ...


11

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 ...


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

You can get a trials bike. They often do not have a saddle or seatpost, by design. They are meant for doing tricks, jumps, balancing, etc. This doesn't sound like what you are doing but if you must not have a saddle, or post, this might be an option for you. This is what they look like: You might want to just use a regular bike and stand up instead as it ...


10

American Classic Cam Plate Design The full name is "Six Pawl Cam Actuated Engagement System." This design is one of the more complicated ones, but according to American Classic provides a stronger freehub with relatively low resistance and causes all 6 double tooth pawls to engage simultaneously with high precision. Mechanism There are several parts to ...


9

Regarding handlebar selection, aero bars are only allowed in the pursuit (individual and team) and time trial events (1km TT, etc). All the other track events are drop bars only. Wheel selection is a little more dependent on the rider's preference, though this is regulated as well; dual discs wheels are allowed for track time trials (essentially the same ...


9

Most trials bicycles are designed without a seat. However, they are likely to be uncomfortable when ridden for long distances. You may want to consider what what you mean by "stay fit". Fitness must have goals to be obtainable. Cycling is generally consider to be cardio exercise that improves aerobic fitness. Standing while cycling is more of a strength ...


9

It used to be, back in the days of ten-speeds, that the tooth counts were carefully chosen so that one could shift a "half gear" by, say, shifting the rear two cogs to the right and shifting the front one cog to the left. Such a design allowed fine tuning of the gear ratio, while still allowing the gears to span a broad range. However, when rears went to 6,...


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: ...


8

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 bike ...


8

The wheel itself is not asymmetric, but the rim is. The reason for this is that the cassette hub itself is asymmetric, and shifting the spoke attachment at rim allows more even spoke tension. The clear benefit of even tension is durability. On one hand, peak tension and associated stresses are reduced, on the other hand loose spokes cause problems and ...


8

The overlap in gear ratios that are available with each chainring is mainly a consequence of the practicalities of building a derailleur gear system. I.e., how many sprockets and what sizes can be fit on the rear hub and on the crank, but it also has useful consequences. Using the example you give above, the cassette has only 7 sprockets and a narrow range ...


7

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 ...


7

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, ...


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 trade-off,...


7

I would be willing to guess if ridden correctly equal amounts of exercise could be made from standing up versus sitting down. However.... BOOM problem solved.


7

Star Ratchet and variations This design in it's simplest form is used by DT Swiss. This design incorporates easily replaceable ratchet plates that offer the added benefit of every engagement point transferring torque. A more complicated variation is what is used in Chris King hubs. Mechanism - DT Swiss 1. end piece 2. bearing 3. thread ring 4. axle 5. ...


7

My best guess is that you have a frame made of Gilco Design Columbus tubing used on Italian bikes in the 80s. I could find no mention of Oberriet bike brand anywhere. Maybe a small custom frame builder that didn't get much (any?) coverage. This frame tubing looks a lot like yours In researching Colnago came up often as a bike maker that used shaped tubing. ...


6

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 ...


6

Both answers are correct but I want to add a bit more. The asymmetric in the title also refers to the spoke lacing of the wheel. If you look at the photo, you'll notice that it is cross-spoked on the drive side but radially spoked on the non-drive side. This feature can also be seen below in combination with asymmetric spoke construction. Both the lacing ...


6

Sprag Clutch The sprag clutch has existed in industrial applications for some time: being used in motorcycles, helicopters, airplanes, automotive transmissions, and others. As far as I know, Onyx is the only company to bring it to bicycle hubs. Sprag clutches offer low rolling resistance and virtually instantaneous engagement. They are also reliable and ...


6

I remember seeing courses about how to make a bike frame, but they were not about new designs, they used standard designs and the courses were about selection of tube, welding/brazing, finishing, etc. Perhaps you start by learning to braze, then building a "conventional" lugged steel frame, then develop that based on what you learn in the process. This ...


5

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 ...


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