I have a single speed mountain bicycle with a rigid fork. I ride the bike in trails and despite I have a 2.35 tire in the front inflated to 35 psi, I suffer a bit from impact in my hands and wrists. I think I saw in a previous thread a "soft stem", "spring stem" or what ever is called, it is an articulated stem with a spring inside to absorve most of the energy of the impact. I would like to buy such stem but I cannot find in the forum search or in the net. Please fellas, help me find a "spring stem".