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34

Carbon fiber isn't necessarily a "weak" or "fragile" material. If you had a tube of the same diameter and thickness of typical CF as a typical steel frame tube, that CF tube would be extremely strong and durable. Metals like steel and aluminum are isotropic materials. That means their mechanical properties are identical in all directions. If you have a cube ...


24

First a disclaimer: most of what I know about carbon fiber fabrication comes from aircraft, not bicycles. Also note that carbon fiber is not the only composite that gets used -- just for one alternative, Kevlar fibers can be useful as well (Kevlar is stronger, but also more flexible than carbon). Carbon fiber is strong, but does not respond well to point ...


21

While some will say "it's just supply and demand" and companies charge "whatever the market will bear", I'm not convinced that your comparison is fair to try and determine whether bikes are overpriced relative to motorcycles. Using a $4,000+ road bike and comparing it to a $3,000 motorcycle is comparing the upper end of one product to the lower end of ...


20

Absent some kind of abuse or extraordinary stress (like falling on top of the bike while it's lying on the ground - stressing the tubes from the side, riding with a friend sitting on the top tube...) a carbon fiber frame should outlast the rider. Lennard Zinn covered durability of Carbon Forks for Velo News a while back. Here are some quotes from that ...


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 ...


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 ...


12

To answer your questions No, they are not safe to ride due to risk of the tube blowing out or the tire rolling off the rim. No, I do not think they are repairable (at home). If they were repaired I would not trust them again. I believe that this item is not fit for the purpose of a bicycle wheel. It should be returned to the place of purchase on those ...


10

General rule of thumb, a stiffer frame will absorb less of the input energy and transfer more energy - hence more power from you legs means more power to the wheel. But.... The bikes have different designs, so the aerodynamics of the bikes and the rider on them will be different which will result in different speeds. And then... A stiff frame will ...


9

As the person who made that claim, the reason is that allegedly some greases can attack the epoxies found in some carbon fiber applications, causing a breakdown of the CF structure, and causing expansion which will jam the post in place. The epoxy will otherwise not corrode, so it's not necessary for that purpose. The manufacturers also recommend you do not ...


9

That dimension refers to the depth of the rim. See this article on some particular carbon rims, that includes a cross-sectional diagram. Deeper wheels tend to be more aerodynamic, though they are heavier, and handle worse in crosswinds. Thus, different rim depths are more suitable for different types of races. 88mm rims are almost exclusively used in ...


9

I have never had or heard of a problem. Over at www.velominati.com, one of the rules is Rule #80 // Always be Casually Deliberate. Waiting for others pre-ride or at the start line pre-race, you must be tranquilo, resting on your top tube thusly. This may be extended to any time one is aboard the bike, but not riding it, such as at stop lights. ...


8

Carbon parts will cause aluminum to oxidize, as a chemical reaction which is why seat posts wind up stuck in frames. But that isn't why this is necessary. "Carbon grease" is not actually grease. It's a friction compound which increases the friction between your fancy carbon seat post and your frame. Increasing the friction allows a lower torque on the ...


8

If this is the kind you have, then leaving the bike in there should make no difference whatsoever. This trainer clamps onto the rear axle, it doesn't even touch the frame. When you're off the bike, the frame doesn't have to do anything except support its own weight - there's no possible way it could get damaged. You're probably less likely to damage the ...


7

I've mounted lights with similar clamps on carbon forks with no ill effect (just have to be very careful not to over-tighten the clamp) but a lock -- which is heavy -- might put a too much torque on such a small clamp. Maybe if you could spread out the area over which the clamp attaches to the frame then it might be ok. What about attaching the U-lock ...


7

Markus Storck, lead engineer and owner of German carbon frame powerhouse Storck Bicycles, told me at a conference about 3 months ago that the best ways to tell if a frame is cracked are movement and time. Movement, because a crack will flex if it's through the paint into the carbon, and you put pressure on the center of the crack, and time, because a crack ...


7

That is purely marketing. It's a common ploy with components, but I've never seen it on an entire frame until now. Aluminum and carbon can be used in conjunction effectively, but not in this case. The carbon wrap on that bike is basically veneer. While Schwinn was once upon a time a well respected brand, they suffered a major fall from grace after going ...


7

The problem is not the stress from the weight of your U-lock. The (true) stress comes from the compressional hoop stress of the bracket to the carbon fiber tube. The bracket stays in place thanks to the friction, which requires certain amount of compression. Unfortunately, this hoop compression coincidentally directs at the weakest point of this (tubular) ...


7

If it were a steel frame and fork there would be no question -- steel lasts nearly forever, even when moderately rusty, and can take all sorts of abuse. Aluminum is a bit less robust, but if it only has "a few thousand" miles on it (and not 30,000) and has not been abused (or hit by a car) then it should be good. The problem with aluminum is that it can ...


7

At the shop we generally use a "normal" hacksaw blade. I'd go with finer blade (more teeth per inch) if there's an option. Go slow and smooth (long low pressure strokes) and keep the blade perpendicular to the bars. The tape will probably help but do take care removing the tape or you might cause the fray you're trying to avoid. There are special carbon ...


7

@Gary Has a valid view on the answer, but its also a bit more complicated than that. He has compared a 250 motorbike to a 1000cc motor bike - completely different to comparing a $500 road bike to a $5000 road bike. A better comparison is a 250 GP Motorbike vs a 250 Sports bike vs a 250 Commuter..... Unlike motorcycling, Road Cycling is the new Golf. As a ...


7

Ask yourself this- would you buy a car off of Alibaba to save a few bucks, or would you fork over a little more money and buy a Honda/Toyota/whatever? Buy the name brand bike. If your Alibaba bike's headtube snaps off on a gnarly high speed descent, who's going to do something about it? Not Alibaba, and good luck getting the manufacturer from god knows ...


7

Most carbon rim manufacturers like zipp and enve recommend a brake pad of their own. However, there are typically several pads that will work. Most of these pads are designed specifically to work well on carbon rims. Regular brake pads from alloy rims should not be used on carbon. Zipp recommends the following pads for their rims: Zipp Tangente Platinum ...


7

Short answer: No. Long Answer: I would not use carbon rims for commuting for several reasons: They make the bike look more shiny than you want, attracting all kinds of unwanted attention. I ride my commuter bike in any weather without too much maintenance. Should the carbon rim fail at some point, I at least won't notice a hairline crack until the wheel ...


6

In general, you've hit the high points yourself. The benefits (and issues) will vary by post model, manufacturer, and design. Carbon fiber is a very versatile material engineering wise. Storck makes 2 carbon posts, which are externally identical. But one is a comfort post, which focuses solely on smoothing out your ride, and the other focuses on being ...


6

Personally, no, I have not had any problems w/ carbon fibre mountain bikes. I am currently on my 5th such steed (Trek Fuel EX 9.8) and it is going quite well. My thumb ... not so well. But, that's besides the point. Of note ... I weigh 145 lbs and ride the bike for what it is meant. I have seen many broken carbon frames. Like wise I have seen many broken ...


6

The best thing you can do is contact the LBS (local bike shop) or online shop where from you got the bike. They'll tell you what to do (most probably handle it with the distributor themselves or tell you to contact the distributor directly). Take good photos of the issue and forward them to the ones you contact. Keep your purchase receipt handy for when ...


6

The real problem with carbon is that it only has two modes -- not broken and broken. When stressed beyond its strength limits the carbon fibers break and the frame is seriously weakened. Plus, once this has happened, the "threshold" for further damage drops lower and lower. And, except for cracks that MAY OR MAY NOT be reasonably visible, there's no ...


6

At the risk of getting beat up on carbon will give it a try. CF seems to be a sensitive subject. I don't agree with your assertion CF are engineered to be strong in certain directions and relatively weak in others. They are designed to have different flex in certain directions - not weak. If I had 4 bikes I need to use as step stools I would go with ...


6

UD, 3K and 12K specify the carbon weave pattern. 3K means there are 3,000 filaments per "tow", 12K means there are 12,000 and UD means unidirectional (no pattern): The construction of bike parts is always UD, only the top layer when naked can be specified to these different finish types. Also there is usually an option to choose between matte or glossy. ...


5

I would be concerned. The bottom bracket is the most heavily stressed part of any bike, and carbon has a catastrophic failure mode--that is, you don't get any warning. One minute it seems fine, the next minute, you've got carbon-fiber shrapnel. As a first measure, I might clean it up as best as I can, take some pictures, and send them to the manufacturer or ...



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