Have been thinking about building up a hardtail from all the parts & a set of 29er wheels laying around. Having issues finding a decent hardtail with a 9 x 135 rear. Stumbled across some BXT frames from China on eBay with a 9 x 135 rear for less than $300. Anyone got an opinion on these? I have a Niner Jet 9 and a Santa Cruz 5010 so this bike will be strictly for double track & rail trails so it won't see the abuse my other 2 bikes get.