Here is a sample letter for Senator Shaheen.  Please feel free to use this as a basis and submit your comments to the Senator's contact page :

Dear Senator Shaheen,

I'd like to be able to bicycle in Wilderness areas if the local rangers allow it. I hear that Senator Lee of Utah is going to be reintroducing legislation to restore their ability to allow this for bicycling and other human-powered travel. He introduced S.3205 in 2016, which proposed the same thing.

The Wilderness Act of 1964 didn't direct federal agencies to close off multiple forms of human-powered exploration in our Wilderness areas, but between 1977 and 2000, the agencies implemented blanket bans without consulting Congress. They forbid their own employees to allow bicycling even if the employees, the people who know the terrain best, think it would be benign or even helpful to management of the area.

Senator Lee's modest legislation won’t mandate opening any trails or waterways to bicyclists, parents with baby strollers, or pedal-powered canoeing. It only returns the decision-making level to the federal staff on scene. Please co-sponsor Senator Lee's legislation.