Attention people who know what they are talking about! (frames)

I have access to a lot of equipment, and a fabricator, that says he will make me a frame. but i need to know what type of metal and thickness to get.

I am thinking some 7005 aluminum. I want it be light…

anyone help?

Are you planning on a welded tube style crown or CNC? I would say either 6061 or 7005 would be the two alloys you would be looking at, depending on the design.
You might want to draw up a rough design of what you want, and then ask the fabricator what grade(s) of alloy would be best, and if you really want to keep the weight down, you could order some double butted tubing (thicker walls at the ends of the tube than in the middle).
It’s really good to see that so many people on here are designing their own stuff.

Here is a quick comparison of 3 frames, each of different materials.

KH 20 - 7075 T6/470g
Koxx XTP - 6061 T6/610g
Koxx Devil - 4130 steel/739g

I don’t know what I am talking about with frames and materials, but once upon a time I had a Wilder unicycle that had a frame made from 6160 Aluminium. I remember it being a nice and fat looking frame and it cost a small fortune but there must have been some reason the framebuilder chose that material.

I plan on it being a tube style frame, something similar to the design of the triton.

also, this frame will not have a seatpost. the bracket thing (the part that attaches the seat to the post) will be welded directly onto the seat tube, leaving no need for a post, and saving weight.

It would break alot easier with no seatpost cause all the stress would be on the frame.Unless it was made out of something better than aluminium so i think titaniums the way to go.Good idea for a big weight saving though

Bad idea IMO.

You will break the frame and not the seatpost then… It will break… may not be soon, but it will happen.
Its better to kill a seatpost than to kill a frame.

anything will break within a certain amount of time if you ride it long enough, and hard enough. i dont expect it to last forever.

i have ideas on how i could prevent breakage and the crown, and at the seat post. The seat tube will be similar to how the qu-ax reinforced seat post is.

if it breaks, no biggy. im not to worried about it. its just an expirement.

p.s. do you know how expensive Ti is? and how hard it is to buy the right size? and the Ti rods that are needed to weld it?

ive been researching making my own frames as well. from what ive gathered 6061 alu. is popular and plenty strong. the guys at the metal store i went to said that 7005 was going to be about $100 more then 6061.

and Ti is totally nat as bad as people say it is as far as money goes. its not that bad if you weld it your self…

if you are an experienced welder, its no big deal to weld if you just read up on some Ti welding techniques

hmmmm… thanks for the info jeremy. ill talk to the fabricator. but is that a tube that they are selling, or a solid pipe. i need tubing that needs to be thin enough that its light, and thick enough that it is strong

yeah, thanks! ill look into the 6061.

what about stiffness? you need to carefully think what you require in terms of stiffness and strength, the two things are not the same and a design that favours one may not favour the other. People just clean snapping the tubes of their frames seem pretty rare to me, and when they do it appears to be a fatigue caused by the culmination of much riding, rather thn a single event whihc causes yield. Therefore is the strength of the tubes really so important? It is often said that design is more important than material, in this case it would seem the design of joints is paramount as this is where most frames seem to break.

Just a couple of thoughts.

thanks for that website, that might be where i get my metal from.

kington99: thanks, thanks for the ideas, ill keep that in mind in the design stages.

also, will 6061 aluminum weld to 7005 aluminum? I plan to buy the KH bearing brackets for my bearing housings.


Before you order online, id go look locally at your shops. Over here we have places that you can go and if you just want a 3 inch chunk of of steel tubing, they will grab out a tube, cut off 3 inches for you and you buy for a few dollars.

A lot cheaper than online and you can also talk directly with them about your idea which is always a nice thing.

So youre planning on making a long neck?

yeah it has to be a longneck cause im a tall guy (6’2’’)
and yeah my brother is actually the fabricator. and he works at the shop with all the equipment. He has all the scraps i could ask for.

now i need to know how if its a good idea to weld 6061 to 7005… and if that doesnt work its gonna be tough to figure out a way to attach them.

on second thought, i could probably use the same design as the old bedford Ti frame.

they use the same kid of filler rod… so i dont see why not

okay ill look more into it.

If you weld the top seat post part right to the frame, that’s pretty stupid. You’ll snap it, and the frame will be useless, plus you won’t be able to change the seat height and personally, I think it’s a really bad idea. Actually, especially if you use a good material like aluminum or titanium. You may as well build it right, like if it’s an experiment, why not have it last longer?

Seriously, make the seat post separate.


Im sure if someone built the post into the tube, they would have it at the right height for them. I cant remember the last time I adjust my seat.

Hmm, actually I adjust my seat quite a bit.