Trend of Material Application in MX/BMX protectors
MX (motocross) and BMX (bicycle motocross) are two of the extreme sports and are considered that full and sufficient protection is a must as performance. This leads to an interesting issue: what are the proper materials for protective items or so called “protectors/gears/armors”.
Few criteria seem to come first when considering of MX/BMX gear development: Light Weight, Great Strength, Long term Durability, and Good Fit (Flexibility).
By reviewing MX/BMX catalogue of several famous brands, i.e. 661, ACERBIS, ANSWER, EVS, FOX, MSR, THOR (in alphabetical order) and etc, it is quite obvious to observe before 2009 the current dominant/favorite materials of protectors are PC (polycarbonate) and PP (polypropylene) which possess the advantages of greater impact resistance and durability.
| Properties | ASTM | Chemical Name | PP | PE | PC | |
| Physical Properties | D792 |
Density g / cm3
|
0.91 | 0.93-0.96 | 1.20 | |
| D570 | Water absorption % | <0.01 | <0.01 | 0.24 | ||
| Mechanical Properties | D638 | Tensile strength kg / cm2 | 330 | 250 | 645 | |
| D790 | Flexural strength kg / cm2 | 420-560 | 70.0 | 960 | ||
| D785 | Rockwell hardness | D70-75 | D65-70 | D75-80 | ||
| D256 | Izod impact strength kg cm / cm with notch | 3.8 | 20.0 | 12-14 | ||
| D1044 | Taper wears mg / 1000 times | 40.0 | 13.0 | |||
| Friction coefficients | 0.30 | 0.17-0.08 | 0.36 | |||
(Quoted from http://www.hwayu.com.tw/table.xls)
In 2010 designs, there seems to be a trend that many famous brands have released new items made of CARBON FIBER in the body frame structure. This reinforced compound material has the features of “high tensile strength, low weight, and low thermal expansion” (Carbon Fiber from Wikipedia). Now it has drawn the attention of the MX/BMX industry and taken further to apply on the protective gears. Examples can be given by Cell knee guard from Asterisk; knee brace MX K700 from Podmx (FOX), and WEB from EVS. CARBON FIBER protectors are/ will be soon available in the market.
On the other hand, it is also noticed that so far very few items employ Carton fiber in MX/BMX. So it is taken further of having a discussion about the reasons why carbon fiber sets up the hurdles that is difficult to be wildly applied.
Carbon fiber of course has advantages of light weight, good impact strength, strong hardness, and flexible ductility. However, those benefits also cause problem to the manufacturers by slow speed in manmade production, and difficulty in shape forming. Overcoming the problem implies increase cost in process and add obstacle on selling products to the end users, especially the non-expert plays. High price often leads buyers’ hesitation, no matter how good in quality an item can offer.
Overall, it is for sure that the never out-of-date rule and trend for the frame materials used in the protective armors are:
1. Light in weight
2. Strong in structure
3. Great in flexibility
4. Comfort in ergonomics
5. Friendly to environment (quite popular nowadays)
(The more the better)
6. And, Less cost in price, of course
(The less the better for manufacturers and buyers)
After surveying, there seem not any material which has met all the conditions above; therefore, it is always an important task for the vender to seek the balance of cost and functions among the raw/ compound materials. Since active and fashion-oriented characters lie deeply in MX/BMX industry, it can be predicted that the evolution of materials in this field would never end.
Great More Yield International Co., Ltd.