Machine Politics vs L'Équipe, August 2010. Photo by Steph Simcox
26" bike polo frame project - wall thickness tubing advice needed
Hi guys so I am starting to design a bike polo frame and I am needing some advice in the wall thickness of the tubing. I am planning to use SAE 4130 Chromoly Steel for the tubing and I will have someone do the welds with TIG. I am not a frame builder and the tubing I choose it is from what I thought it would make a sturdy bike but maybe the wall thickness in the tubes are not the best or right ones. I used the American bottom bracket spec cause here in Argentina it is easy to buy 3 piece bmx cranks for a reasonable price and having the option to access to a bunch of options when it comes to chain wheels.
My aim do something like the geo of the joust, I hope some of you guys could lead in the right direction with this project. Thanks in advance!
Head tube: ------- (ID 34mm) - (OD 36.5mm) - (Wall 1.25mm)
Top Tube: -------- (ID 31.8mm) - (OD 33.5mm) - (Wall 0.85mm)
Down Tube: ----- (ID 31.8mm) - (OD 33.5mm) - (Wall 0.85mm)
Seat Tube: ------ (ID 31.8mm) - (OD 33.5mm) - (Wall 0.85mm)
Bottom Bracket: (ID 51.3mm) - (OD 54.3mm) - (Wall 1.5mm)
Seat Stays: ------ (ID 18mm) - (OD 20mm) - (Wall 1mm)
Chain Stays: ---- (ID 18mm) - (OD 20mm) - (Wall 1mm)
*All the tubing is straight gauge of course.
ID = Inside Diameter
OD = Outside Diameter