I am thinking of buying a hardtail from and building a bike using the majority of components from my Trek Top Fuel 8.

Is it as simple as I think or is there anything I should watch out for or pay particular attention to?

Phil

Your seatpost, seat clamp, bottom bracket and headset may not fit, if our bike has a tapered fork that my not fit some hardtail frames, rear axle might be different if the Trek has a 142 rear.

Should be straightforeward.

Budget for a new:

Headset (as invariably it’ll be different)
Front mech (size and pull mean there must be at least 6 or 9 different cominations, and thats without counting all the idfferent direct mount standards).
Seatpost
Seat clamp.
Forks (if you have a tapered steerer now it wont fit in a straight frame)

Some of that might fit, but odds are they wont and it’s rarely worth trying to narrow down a bike that’ll fit everything, pick one you like and buy the bits to fit it. The exception is proably the forks which cost £££.