Help for tube sizes

Hello! Im looking for some advice on materials for my project.

So I'm going build my own motorcycle from the ground up, I've made a design I think will work well. But now I'm looking at the materials i'll need for it, I've decided im going to use mild steel for the frame (based on my skill level and having a gas mig welder). Im trying to figure out what size tube would be the strongest. Someone I know suggested sch80? What would someone woth more experience recommend or how would I go about figuring it out?

I've contacted my vehicle standards for where I live and asked about the regulations, he said there wasn't much in the way for regulations on custom motorcycles, but i can build it. I'll go down once more before I buy all the materials just to make sure.

Thanks for your time!

At least as important is the frame geometry. I can't advise you on specifics, other than to recommend a LOT of attention to welds, but there is a lot of specific information on-line regarding their design and contruction - do a search using "how to design a motorcycle frame?" and you will find a lot of help.

Hi Austin. Great question and something that can be a little difficult to answer as the design has a large bearing on the strength. What I do know is that most motorcycles have very thin and compliant frames meaning they are built with a level of flex. As a home builder we don’t have that option of engineering such things so we usually just make things a little heavier and a little over engineered to make sure we stay safe while riding. I looked up what sch 80 pipe has in the wall thickness and it’s around 4mm for the size you would use on a motorcycle. I think that’s a little overkill and would like to see 2.6mm or even 3mm at a diameter of 1.25 or 1.5 inch diameter. If you can get 1020 CDS mild steel (cold drawn seamless) it will weld very nice and have a nice uniform quality. Thanks for the questions and keep us up to date with your project. All the best!