Thank you Baltic,
About visa, my idea is travel into Lhasa in the friendship highway and because of that the visa of Nepal is not enought.
I´m reading a lot of posts and some books and all of them refere the dificult about getting a visa to enter in China.
welcome, no problem.
yes, a nepalvisa is not enough, and even a chinavisa wont help you much (met a cyclist last year in nepal, even with a valid chinavisa he got refused to enter tibet from nepal). independent travel onward to lhasa is a very difficult topic. the easiest option is to go with a tour from ktm (flight into lhasa and cycle back), but this will be much more expensive.
if you are fixed to ride the friendshiphgw maybe going into china and then onward to nepal might be easier, but also is (legaly) possible only by a group.
i think everybody hope that the situation will be more relaxed soon like before 2008...