Legislation to open wilderness areas across the country to mountain bikes is drawing expected, and unexpected, opposition.

The Applachian Trail Conservancy worries that if the legislation sponsored by U.S. Rep. Tom McClintock, R-California, becomes law that hikers on the iconic footpath that runs from northern Maine to Georgia could find themselves dodging bikers on some sections of trail.

"If passed, H.R. 1349 would fundamentally change the A.T. hiking experience in wilderness areas," the trail group said in an email plea to raise opposition to the legislation and donations to the organization. "Hikers would lose the quiet and contemplative nature of the Trail in these protected places and be forced to constantly monitor the Trail for mountain bikers."

The Conservancy also worries that mountain bike use of trail sections would lead to "overuse and erosion caused by bicycles in wilderness areas" that will "require substantially more intensive maintenance from our volunteer clubs and crews."

In somewhat of a surprise, also opposing the legislation is the International Mountain Bicycling Association, which seeks more access to trails in the National Park System.

"IMBA will continue to respect both the Wilderness Act and the federal land agencies' regulations that bicycles are not allowed in existing congressionally designated wilderness areas," the group said in testimony presented to Mr. McClintock, who chairs the House Natural Resource Committee's subcommittee on federal lands. "IMBA is not supporting H.R. 1349. As part of our commitment to trail access and public land stewardship, we have been involved in discussions about wilderness and other forms of legislatively driven protections for public lands for decades. We find that when mountain bikers are given a seat at the table in these discussions, we can protect important trails while finding common ground with those who are looking to create new conservation designations."

Dave Wiens, IMBA's executive director, said public lands face enough issues right now and the outdoor recreation community doesn't need divisiveness.

“Mountain bikers and the recreation community depend on public lands and thoughtful conservation. Public lands are being threatened at an unprecedented level right now, and it's imperative that public land users come together to protect these cherished places and offer our voices in this critical dialogue,” said Wiens. “We know Wilderness hits some mountain bikers’ backyards, and we understand why those riders support this legislation. To continue elevating mountain biking nationally, IMBA must remain focused on its long-term strategy for the bigger picture of our sport.”