i want to start modifying one of my track frames.
im just looking for some help for ordering my tubing for the project below
heres the scoop:
ive been cycling for maybe 2 years, and now that ive learned a little bit about frames and geometry i want to modify my beater fixed gear. i'm an engineering student, and ive been welding for about 4 years, so i know a little bit about structural integrity, ect
i want to cut out my downtube, then weld a new tube in that goes from about half way up the headtube to a few inches up the seat tube. then i will gusset the corners.
im doing this for a few reasons,
1. i want to be able to do barspins, and
2. because i like to work with metal and i take pride in my designs.
im a kid, i do tricks on a track bike. if you want to debate about it, please do it in a different thread.
heres my idea
-sorry the pictures are so crude, but they get the point across.
keep in mind i exaggerated the downtube position in the second picture to emphasize my idea. it wont be THAT high. only an inch or so higher
before:
after:
im not sure if the gussets are necessary, they wouldnt really add THAT much weight if i used 20g metal.
any advice/comments for keeping the frame stiff are appreciated
will i need to build a jig to hold the frame from warping once the downtube is out? or should it be alright? i plan on just using a demel tool, nothing crazy
my MAIN QUESTION with this is: what wall-thickness should i buy for my new downtube? i was thinking 1.25" OD
thanks,
Greg Hebard