Here is the 4130 heat treated chromoly tubing that Synergy sent us. It’s 13⁄8-inch, 0.188-wall tubing, which is not absurdly thick for a crawler. But because of the heat-treating, the chromoly tube actually has a higher tensile strength than 11⁄2-inch, 0.250-wall regular tubing. This maximizes the strength of the parts while saving unsprung weight over the heavier-wall tubing. Since the tubing is heat-treated, you should not weld tabs on the drag link or track bar. If you have to attach something, Synergy offers a clamp (PN 3112-A) that you can use.