Metal to use when building a swing arm?

[Hombre Verde]

I am thinking about building a swing arm for the bike that I am working on. Not sure if I should use round or square/rectangular tubing. Also, not sure what type of steal and the thickness that is required. I know a lot of factors go into this, just trying to get an idea.
Thanks,
J-man

 

[Sects]

I am thinking about building a swing arm for the bike that I am working on. Not sure if I should use round or square/rectangular tubing. Also, not sure what type of steal and the thickness that is required. I know a lot of factors go into this, just trying to get an idea.
Thanks,
J-man

Full swing arm? Or extension? 1-1/8" 120 wall if you can find it...
1" and 1-1/4" will also work, same thickness. DOM, round.

Posted via Mobile

 

[Hombre Verde]

Not sure yet. I might just use the swing arm pivot and build a new one from there. What type of steel would I need? I have seen a bunch of different types. Is there an issue with strength depending on the actual metal?

 

[Sects]

Go with DOM round 120 wall thickness. Not crazy thick but super strong.

Posted via Mobile

 

[Hombre Verde]

Cool. I will look for some of that.
Thanks

 

[Cafe-Dave]

Weldments tend to fail at the weld, if anywhere. Good Technique and Good Material are equally as important. Hydrogen embrittlement can be a problem, but I doubt you'll be SEM inspecting anything.

Be clean, keep the area shielded with gas properly, and make sure you get enough penetration. Just typical of building anything as a weldment. If you're really concerned then a normalization of the weldment may be worth looking into.

Some more discussion

http://www.pirate4x4.com/forum/showthread.php?t=659544

 

[TwoJugs]

What are you looking to do with the swingarm? Stretch it, strrenghten it, widen it?

 

[Hombre Verde]

Was thinking of a mild stretch and widening.

 

[bobber bill]

if you are going to cut up your existing swingarm and reuse the pivot portion, you will need to use mild steel. 1 1/8" cold rolled 120 wall round tubing is what you want in order for everything to blend in and weld well. this tubing size is the same as the rest of the frame, so it will all flow together nicely.

DOM is nice but not necessary unless youre planning on doing a lot of bending/shaping to the tube. regular cold rolled mild steel is much cheaper and readily available

 

[TwoJugs]

Like BB said, you need to use steel that will weld easily with what you already have from Yamaha. I used DOM tubing inside to slug the pieces together. Probably over doing it but I didn't need much and wanted the max strenght. Take a look at the youtube clip to see how I pulled mine off.

 

[Travis]

... 1 1/8" cold rolled 120 wall round tubing is what you want in order for everything to blend in and weld well. this tubing size is the same as the rest of the frame, so it will all flow together nicely. ...

The swingarm uses larger tubing than that... Closer to 1-3/8" but still .120". Swingarm braces are usually done with 7/8" or 1" tubing with about a .090" wall


Twojugs, there's something wrong with your video I think.

 

[TwoJugs]

The video seems to be working now. I guess it took a little while to lock on with youtube.