What are the advantages of a Full 4130 Cr-Mo Double Butted Alloy Frame set versus a Full 4130 Cr-Mo Alloy Frame set?

And is it worth paying the $70 difference?

Double butted will be lighter.

https://en.wikipedia.org/wiki/Bicycle...#Butted_tubing

Its also about aesthetics. If you like a classy look: go for double-butted, quill stem fixie. But if you want a more modern fixie then get the tooth-paste welds.

Butting has nothing to do with asethetics. You think there are no welded frames with butted tubing?

After riding both butted and plain tubing I'd pay the premium for butted. But it really depends on what you plan to do with the frame.

Maybe he is confusing butting with lugging?

probably

Right on the money sir. I feel pretty dumb right about now : \

at this point I don't plan on making additions/subtractions to the bike right now. i plan to use this bike for commuting a few miles a day to work and back home

thanks all

Bending stress occurs at the joints, not the center of a tube, thus material can be removed from the center of a tube. Look at this bridge, it is built according to the same principles. Lots of material at the ends, less material at the center.

I choose lugs over butt welds for similar reasoning. A butt welded frame has a stress concentration right at the highest stress locations. Lugs are better, less heat introduction, stress is transfered via a lug.

The reason more bikes are lugged $$$$, it's costly to use lugs.