jays0n
Adventurer
My trailer has a rack that is currently built out of 1.5" square tubing. The rack is too tall for much offroading, the CG is just too high. I knew this might be an issue when I built it but figured I'd tackle it when it became a problem. Well, it's a problem so here I am. I will be using linear actuators to raise and lower it and have all that figured out. What I'm not sure about is what size to use for the tubing. My plan is to keep the lower parts of the legs and add the larger size tubing to the rack so as to not have to worry as much about water getting into the legs, plus it will be easier to modify the existing rack this way. The OD of the existing rack with a fairly heavy coat of paint that will be removed from the telescoping sections is 1.516" and I found telescoping tubing (no inner weld protrusion) in 2" OD and 1.75" OD, both 0.105" wall. The clearance calculations are below but my question is how much clearance is too much (rack will rattle around) and how much is too little (rack binds)?
2" OD x 0.105" Wall Square Tubing with 1.516" OD Square Tubing Telescoped Inside
2 - 0.105 - 0.105 = 1.79 ID
1.79 - 1.516 = 0.274 total space between tubes
0.274 / 2 = 0.137 space on each side of inside tube
1-3/4" OD x 0.105" Wall Square Tubing with 1.516" OD Square Tubing Telescoped Inside
1.75 - 0.105 - 0.105 = 1.54 ID
1.54 - 1.516 = 0.024 total space between tubes
0.024 / 2 = 0.012 space on each side of inside tube
It seems obvious to me that the 1-3/4" OD is going to be too tight, even with the paint removed and the surface greased so that means I'm probably going to have to go with the 2" OD instead. That leaves me with a bit more than 1/8" of clearance around the inside tube. Is that more than I want or just right?
2" OD x 0.105" Wall Square Tubing with 1.516" OD Square Tubing Telescoped Inside
2 - 0.105 - 0.105 = 1.79 ID
1.79 - 1.516 = 0.274 total space between tubes
0.274 / 2 = 0.137 space on each side of inside tube
1-3/4" OD x 0.105" Wall Square Tubing with 1.516" OD Square Tubing Telescoped Inside
1.75 - 0.105 - 0.105 = 1.54 ID
1.54 - 1.516 = 0.024 total space between tubes
0.024 / 2 = 0.012 space on each side of inside tube
It seems obvious to me that the 1-3/4" OD is going to be too tight, even with the paint removed and the surface greased so that means I'm probably going to have to go with the 2" OD instead. That leaves me with a bit more than 1/8" of clearance around the inside tube. Is that more than I want or just right?