Originally Posted by
tomtomtom123
I got the stainless steel struts but they're super stiff. Will this be a problem for the mounting holes in the aluminum frame? I'm worried whether the dropout plate or the holes or the threads will crack if the strut is not able to bend and reduce the impact load like the aluminum struts.
I made the mistake of not double checking or asking chat GPT to show me how it calculated its recommended thickness of 3.8 mm for stainless steel without holes for the equivalent stiffness of 4.6 mm aluminum with holes. Now it's telling me 2.7 mm. And that my strut at 4mm is actually three times stiffer than the original.
I'm wondering if I should take an angle grinder and cut a 1 mm deep channel into the stainless steel to reduce its stiffness. Or is this fine and I should leave it alone?
Frame vertical struts are, in engineering terms, "slender buckling columns", and resistance to buckling is based on stiffness, not strength. That should work fine, and under a high lateral load at the top, should deform low near the mount screw, or just bend elastically.
Of greater concern is one hole through the strut looks threaded. If same at the lowest hole, that needs to be a close clearance hole, not threaded, in order to tighten at the frame dropout threaded holes. Unless the upper hole there is to attach something else.
EDIT: With that thickness, make sure your attaching bolt is long enough, to use full thread depth at the dropout. I use bolts that are long enough to poke out the other side, at minimum to grab to unscrew it in case the bolt snaps off flush on the outside (has happened before that, was lucky to get the broken bolt out), and even better, long enough for a nut on the inside to help keep the bolt tight.