Framebuilders - What is the best material for a frame...

if I am going to need to customize it a bit and make adjustments as I go along - either welding or brazing? I also need something that will hold two riders, motor and batteries. It is going to be the chasis for my ebike and, because I am not an engineer, I foresee the need to make small adjustments along the way. I am looking at something that with 26" wheels. ==strong, weldable and not too expensive :)

That could in theory be a lot of things. It would depend on what you are comfortable working with. The lowest threshold for hacking around is composite or steel. Ti is just too expensive, and aluminum is mostly limited to tig, and the more expensive tig set-ups at that, though it can be gas welded...

Steel. Strong, easily weldable and forgiving of mistakes. It is really the only logical choiuce for your application. Do some reading on welding and brazing as well.

The one thing to warry of with steel is that while the material is cheap, one frame gets expensive fast. There are lots of workarouds, but you need a method to join the material, you are probably going to talk yourself into some fixturing, and you need tools to ream the BB, HT, and ST. In all about 500-1000 of tools for the frame prep. You can take your stuff into a friendly bikeshop for processing, the only thing is that if your product is a little weird, they may not want to be part of the liability chain.

Thanks! Are you talking about common steel? or chromoly? or some other mix?

Any steel. All of the bits and pieces Peterpan is talking about would have to be carried out on a mild steel ERW tube frame, or a True Temper S3 one.

Thanks! Are you talking about common steel? or chromoly? or some other mix?

4130 straight gauge for your app. aircraft supply houses have it in most any size. anything cheaper than 4130 will require thicker tubing and wind up weighing a ton. I don't think you'd want any butted tubing as you might wind up "working" in the thin sections--which could compromise the tube. all the fancy/pricey bike specific tubing is butted.