I am making a rear bumper from 3 x 4 x .165 steel and plan to add a swing out tire carrier to it. I have been thinking about a 3/16 tube with bearings over a 1" spindle and was hoping to use 1.5 x .125 square tube steel for the carrier frame. The opposing side of the carrier arm will be securely locked into the bumper. Is the .125" wall strong enough to support a 31" tire on a steel rim? I was going to use 2" square tube, but can't find stock.

Thanks for you input.

 

I'm close to finishing a hitch mounted tire carrier which is similar in design to a Rigd Ultraswing Tire Carrier. For the static and dynamic arms I used 3" x 1.5" x 0.125" rectangular steel tube. There is also some 1.5" x 1.5" and 2" x 2" also 0.125" square tube in it. It's not complete but I've road tested it with a 31" tire with an aluminum rim (XJ Turbine - 15" x 7") and have had no issues. I think you'll be fine with 0.125" wall thickness for your dynamic arm. My experience with building trailer frames tells me that rectangular tube is stronger than square tube and that's why I went with it. Square tubing would probably be fine though.

 

I used 2x2 and 2x3" tube in 1/8" thickness with no issues.