Why famous brand bicycle racing wheels would burn the box?

Recently, many people in the discussion easier to burn carbon side opening box problem, although I have not met, there is no specific cases around the lessons, but I still pay close attention to this issue. I fear that the hydraulic C clip as applied now, the heat accumulation brake side may become more serious. My question is, short-term operation of heavy braking, and a long progressive braking action, which can be a more effective control of the heat accumulation, reducing the risk of burn box? Also, I have a summer program to ride through the Alps, you may need to cope with the more than 22% of the downhill. In addition, the latex inner tube will be more sensitive to high temperatures caused dangerous?

Tube type is not important, not because of the heat and its own flat tire, but because of the tire and the rim can not effectively withstand the pressure coming from the tube will cause the tube to explode.

Here again simply talk about the advantages and the difference between the opening and tube tires.

Tube tire wheel openings will generally lighter than carbon rim, because it does not tire fixed lips, reducing the burden on the wheel frame structure, the cross-section of the rim edge closer to a circle, while not having to worry about the shape of the rim to be Ge the tube leading to the implosion of the tube tire wheel can use lighter and thinner inner tube. Since more rounded rim without causing additional pressure on the tire (tire must consider the opening lap edge uneven tire internal pressure caused by extra). Tube births are often able to support a higher tire pressure when the tire is also more secure because the tires are still fixed on the rim, and the opening may be dug out of the loop stuck tire wheel. Tire will be opening in the radial direction and both sides of the pressure applied to the wheels, tires and tubes will generate pressure in the radial direction of the wheel, which is to maintain the balance of tension wheels also have a positive impact.

The disadvantage tube tire wheel tire tube is mainly the cost of expensive, high cost, and take a long time to smear glue and fixing tires. But also excessive heat and so fail to make glue tube tire pulls out of the loop in case of an accident caused when cornering (Joseba Beloki is therefore crash). By contrast, the opening tire disassembly easier,cheaper and more, in the event of a puncture, usually only need to replace cheap inner tube, rather than replace the entire outside child together. This reduces the cost. Due to the need of fixing bead rim, the rim will be heavier opening, while opening the inner and outer tires and tire tubes compared to the same grade are also heavier.

Carbon fiber with high strength performance when subjected to tension, but when subjected to pressure, its performance is not as good. The primary problem of carbon side opening round, is to install the tire rim need to be able to withstand the enormous pressure tube after inflation. The following question is, at a certain temperature, resin bonded carbon fiber will soften, if overload style heavy braking, you may even see the brake side like a wave curling resin melt off, even into the shell side brake shape.

Brake wheel past the open edge cooling is generally not a problem. But in the opening round of the carbon side it is very important, because the rim protruding from the body, rather than a whole box, carbon brake side opening round will be harder edge cooling, now the top edge of the opening ring carbon and brake blocks specified by the manufacturer can reduce the risk, manufacturers are working on weight restrictions on carbon side opening of what should be many problems, but they found that edge handling and braking, brake block formula, rim shape, braking techniques, riding routes, ambient temperature ...... all about. So it is not easy to figure out.

About big brand factory to burn box to reply to this problem and views are as follows:

Total price of Zipp technology responses for any day of riding the brakes, such as at a traffic light or at the foot of the brake, the brake is not how much difference there,

because you have to brake to stop, and after a period of time within will not brake. Therefore, the temperature of the rim and does not gather. While 98% of daily riding the brakes are carried out, so our answer is how the brakes will not have anything to do. However, in the long-distance or complex continuous downhill, the brake control edge temperature is a very critical thing, we need to brake rim and brake blocks are left out longer cooling time. The most important thing is not to have been with the brakes, which makes brake side, the temperature of wheels, tires and brake block continues to accumulate.

In-house product testing ZIPP, we simulate a 300-pound (approximately 136kg) Knight, from 20% down slope continuous punch 5-6 minutes while the case has been vigorously with the brakes, when the wheels are close to 700 degrees Fahrenheit degree (700 ° F about 370 ° C). Just release the brake, even a few seconds, you can make the rim reduced by more than 100 ° F (approximately 38 ° C), and if the holding brake, even if only a very slight force, the brake system temperature will continue to rise. You are 75 meters or 60 meters before the brakes begin a hairpin, and not very important, but if you keep the brakes downhill, then to the brake system will be adversely affected.

DT SWISS art u replied that, in our experience, more vigorously and short braking is more desirable method, although compared with the brakes gently approach has been the strong and short braking process brakes and brake side block temperature will be higher, but there will be plenty of time left for them to cool, thereby controlling the temperature of the entire brake system. In other words, the low-power long brake, the brake system is difficult to make the temperature down. No matter how the brakes from a given speed down to another speed will need to do the same amount of power, but to the brake cooling system to increase the interval, but let the system cool down, reduce heat accumulation.

When we discuss the specific carbon fiber wheels when the need to consider more specific elements. First, the tire pressures and specifications here will play an important role.

If a driver knows the face of a long downhill, it is best to consider reduced slightly the tire pressure. When the temperature rises rim, tire pressure will increase, there are likely to exceed the circle edge or tire pressure limiting itself. In addition, wider tires at the same tire pressure will increase the pressure on the rim, so it should be relatively narrow tires lower tire pressure. Finally, the probability of latex inner tubes to the heat blew much higher than other inner tubes, please refer to the 2012 Tour de

France Tony Martin flat tire accident. This tube should not be used easily on regenerative carbon wheels (I guess other vendors will have the same advice).

HED technology official said, we focus on the rim temperature problem for a long time, in our survey, the worst case has been gently with a brake is used. Compared to vigorously short brake, which makes wheels temperature becomes higher. Carbon fiber is a poor conductor of heat good, if there is no time to heat, so that it would have been accumulated heat temperature becomes higher and higher. The following facts for reference: No matter how sharp, aluminum wheels are difficult to heat up to 250 degrees Fahrenheit (about 121 ° C) or more, but the carbon rim temperature can easily rise to 450 ° F (232 ° C) or higher. We spent a lot of years to find a more heat-resistant resin formulations, stronger process method, so that the brake side can fight high temperatures.


The next problem is the aging of the tire, I remember the vulcanization of rubber processing temperature of 320 degrees (160 ° C) or so, so the tire and inner tube may be deteriorated at this temperature.



Accompanied by a high temperature of the brakes may not be a problem, also no tire change, but this time maybe the tube has begun to melt. I suggest that if your carbon wheel brake acts experienced high temperature, check the tube there is no weak sticky or cracks is necessary. We are still trying to reduce the
impact of the braking system of the tire.

Renault technical director Reynolds reply, the worst braking mode is "after holding brake does not let go," before we use CTg structure, received burn almost all cases the rear frame, front wheel occurs rarely seen burning box. After applying CTg, burning box case become scarce, nor are the rear wheels. Directly answer your question, yes, yes, less powerful and less likely than the braking time the brake cause heat accumulation. This is what we have always understood. I and others have similar exchanges, we have used a similar experience. Not long ago I Jorg Ludwig chat, he told me, Mario Cipollini, as well as many other professional drivers in the use of ultra-light carbon wheel downhill when they are not burning frame event occurred, but in the amateur market, he and I have the same problems: users can burn occurs box, and often is due to have been holding brake does not let go.

US ENVE test project engineer said, the heat accumulation in the case of the rim will be more influenced by the entire downhill ride in the average speed of. In the process of continuous downhill, the brakes just before the bend, rather than continuing with the brakes, will increase the average speed downhill, and high speed can effectively reduce the temperature of the rim. 1, higher speed, more energy is consumed in the fight against air resistance, rather than consumed in the brake system. 2, the relative flow rates of air to accelerate the heat away easily.

And in some cases, even if the same average speed, different brakes will change the way the heat gathering speed: the use of low power with a long brake braking mode, so that only the outermost layer of the brake block work, without let the brake off the outer layer of the block. Brake block surface loss can take away a lot of heat, which would not protect the rim has been accumulated to very high temperatures. Within the boundaries of the brake shoe wear not have brakes, the temperature will continue to rise and not relieve.

Our tests, will make way rim brakes reach the maximum temperature, it is the moderate strength continued brakes, heavy braking and brake shoe wear quickly control the temperature of the brake system. About rim internal temperature: high frame round will be more difficult than the low round box heating, a larger area of the ring wall is equivalent to the heat sink effect, be able to take the heat part of the edge of the brake. In our tests, the internal temperature of the aluminum frame is higher than the carbon frame. Biding Ji tube latex tube more easily affected by temperature, in the case of prolonged high temperatures cause the brake, rim and tire for any unevenness interface transition (edge, any small burrs, etc.) may suddenly punctured latex tube, regardless of aluminum carbon wheel or wheels have such risks. If they will not face a long downhill, the latex inner tube well, but we do not recommend the use of a latex inner tube, because it is not safe in some cases.


Source & Author: Zinn Lennard