To move down through the mountain it is important that you go down slowly, thus it becomes a necessity for mountain bikes to use heavy weight materials so as to reduce the speed of the vehicle.

要下移，通过山，重要的是你慢慢下降，由此，成为一种必要的山地自行车使用重的材料，以降低车速的车辆。

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On the slopes, this allows you to ski down a gigantic mountain at high speed.

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