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View Full Version : Tube size for hard tail frame?



Lza555
06-30-2017, 10:49 PM
I'm wanting to try to build my own complete Hardtail frame and need some beginners advice. Would 1"OD DOM with a .120 wall be strong enough? If not what's the smallest size that would still be safe? Not trying to cut corners but tube bending dies are kinda pricey and I already have the 1". Plus I just like skinny choppers.

Zeeman
07-06-2017, 2:55 AM
.120" wall DOM is adequate. Frame strength also depends on your design, good fitup and quality welding. As well as using a decent jig to build the frame.

Check this link for some good information on tubing:

http://www.chopperhandbook.com/tubing.htm

Also a rundown on a basic frame build:

http://www.chopperhandbook.com/oldschool1.htm

53Bash
07-06-2017, 11:26 AM
I used 1" x 0.12" 1020 DOM for my fork. Its a triangulated structure not unlike the rear end of a motorcycle. I tested it for braking forces of 1,500 lbs, which would be enough to kick your rear end up at about 3g - a nasty bump that would likely cause a crash. It didn't even flex significantly, let alone come close to failing (the potential failure point that drove my was testing was actually elsewhere).

Point being, if a couple skinny triangles made of 1x.12 dom can hold up to this, I think its fine for a hard tail where you have better bracing angles etc. A possible concern would be fatigue, since you'll have more vibration (from engine and road surface) than my spring-mounted component. But that's less about the tube, and more about the design & implementation of welds / gussets etc.

http://i.imgur.com/fLuQ6En.jpg

http://i.imgur.com/DyZ60s0.jpg