I dusted off my very rusty Strength of Materials education and did some math(s)… I probably messed something up, but here’s what I came up with:
Assuming most of the compliance feel/noodleyness of the front triangle comes from torsion, I looked at the formula for twist angle of a thin tube. Here’s my math, note the assumptions about applied torque being equal, tube length being different, thin tubes, and shear modulus being equal. Also of course this assumes straight gauge tubing.
plugging it into excel, here’s what I got for needed 7/8" wall thickness to get an equivalent angle of twist to a slightly longer 0.035 1" tube if the same amount of torque is applied to both:
