get it on its wheels, put the tank on and place the seat unit where it needs to be, that'll give you a better idea when making subframe , and where mounts need to be
Think Yan explained that to me some time back...good to be reminded before i go and buy one...however if i can find this place that sold pre bent tubes in mild steel for a short-ish length it would save a few quid. There's plenty selling stainless, mostly for exhausts but i need mild. It did cross my mind to see if there’s anything made from carbon fibre out there...probably a good reason why i ain't seen no carbon subframes on the net!Just be careful as a pipe and tube do not have the same OD for a given nominal size. That means the dies on a pipe bender are going to have a larger ID than those for a tubing bender. If you’re only doing small bends it may not matter but for sharper bends tubing may kink.
I looked up automotive racing roll cages from a big racing product store here in the US (Summit Racing). Most of the cages they sell are 1.625” (41.3mm) x 0.120” (3mm) in DOM mild steel.My measurements for the top rail is 38mm OD, 3mm wall thickness and the bottom rails are 31.5mm OD, 2mm wall thickness.
The supplier is offering 38.1mm OD, 2.64mm wall thickness and 31.75mm OD, 2.03mm wall thickness all CDS which they say is stronger than mild steel.