Verdant Welkum misses the point here.
As a legal matter --interpretation of statutes applicable to wilderness designation in the USA-- mountain bikes are not expressly prohibited in wilderness.
The whole problem centers around "mechanized" prohibition, and not "mountain bike" prohibition.
If we are literal, "mechanized" means anything mechanical.
Does the legislative history prove "mechanized" meant "mountain bike"?
US Forest Service interprets the term "mechanized" as excluding MTBs.
That's why we are in this situation.
Strangely, mechanical ski bindings, mechanical horse saddle/bit/bridle fastening, mechanical cooking stoves, mechanical backpack fasteners/cinches, zippers on clothing (which are mechanical), shoelaces, belts and suspenders -- these are not seen as "mechanical" such that they enable "mechanized" transportation within wilderness.
Why do you think that is?
We might hope Ted Stroll & Co at STC are on top of this, but I'm not convinced. I see STC functioning like Sierra Club did in its early days, and just as likely to end up shilling for the ideas and values originally meant as targets for dissection and redefining.
I'm not persuaded they'll follow the right path, Stroll is a CA state employee who works as a deferential-to-govt-authority research attorney for CA Supreme Court.
I believe STC will preserve the status quo while pretending to work to change it, just like IMBA has done.