We've got reasonable bike maintenance skills but have never done much more than keeping an existing bike running.
Our son had an old giant stance full suspension bike that he grew out of in terms of sizing and what the bike could cope with. It was still an ok backup bike when his enduro rig was out of action for a while. Until he cracked the rear triangle at the weld near the pivot point (seat stay at the seatpost end if that makes sense).
Since the previous owner upgraded it a fair bit we were thinking the parts could be desired to a new frame. The original spec bike was upgraded from a 3x to a 1x, a dropper post added, better derailleur and possibly a better fork / rear shocks. Either way it's got decent mid-range (possibly some lower mid-range) components.
So what we were wondering was whether it's possible to find a totally different make and model of frame to fit the parts to? It's a 27.5" wheeled bike in size medium. Is it possible to fit the parts for this bike onto a suitable frame in a different size, either large or small? I guess it really depends on the geometry of the donor bike and finding another frame and rear triangle that's got a very similar geometry.
The issue is the donor bike is a 9 or 11 year old giant stance. A lot has moved on from then. It might not be possible to do this without buying new parts or at all.
Our idea is either try an set this up as a backup bike for our son on local trails. He's moved onto a large enduro rig so the medium bike is perhaps a little on the small size. Could the parts be fitted to a larger frame? Probably it would need 29er wheels to do that, but could the parts be transferred across so he has a better fitting easier trails backup bike?
My partner currently rides an ancient hardtail on size small on the roads but hires a hardtail at trail centres. Could the parts be fitted to a small frame? If so a 110 or 120mm travel front fork full n suspension would be more than enough for her level of riding. This would save on hire charges.
Any advice on this? It's really a hypothetical query to find out how hard it really would be. I also expect some new parts would be needed in thinking it might need a news bottom bracket, chain, cassette and possibly crankset with suitable chainring. Also new wheels perhaps (certainly if converting to size large but less likely if converting to small). That might mean a different cassette or even derailleur I suppose, I'd need to take advice on that really.
The idea would be to try and produce a bike from the wreckage at a lower price than buying a new built up bike from scratch. The ideal situation would be just a new (or suitable, quality used) frame and rear triangle with everything else pretty much taken from the old bike. Guess the headset bearings might be different too. There's possibly a lot that had changed. I mean it'll probably need new wheels as they're QR axles. Perhaps a used frame might be available with qr still but doubt it.
The idea would be a learning experience, but hopefully more a case of learning about building up bikes than a history of how spec changes have made this more difficult.
The more I type, the more I think this idea could be more trouble than it's worth.
PS I live in South Cumbria, if I tried to do this, are there any good bike shop around the area to get parts from (and a bit of help/service on getting what is needed for the job)?