I need a new back tire and will probably order one tonight seeing as i don't want to be without a bike for long. I have michelin powers on currently and the front is holding up great but the back has become odd shaped. I want something not as soft as the ones i have on there but i don't want something to hard as to where it has no grip. Any suggestions and where to order them? Thanks.

Also what oil should i run during colder temps? I will be riding this thing for as long as i can stand the cold.