I started with an old (cheap) mountain bike that I didn't use for years. A Dept store bike. I have it running the way I want. but now would like to fit some suspension : forks and a seat post. Suspension would be a safety issue on these bikes, as I hit some hard bumps trying to dodge cars. It seems that these old cheap bikes aren't very upgradeable. The steerer posts and seat posts are too small compared to newer ones. I found a bike shop near that has a lot of old parts and I may swap frames to get a newer one that can be upgraded. He already sold me an alloy front wheel to fit disc brakes (I had a brake kit) and a suspension neck for the bars (that wouldn't fit the old bike.) His price is cheap and He loves the MB. project. I left him a list for with old frame and with a new one. With luck be with me, it may come together.