Quote:
Originally Posted by biketopia
To prevent flex??
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More for increasing the structural strength is my bet. Since the arms were originally 2 pieces of C-channel butted together & spot welded, they could in theory (reality) come apart. I had one split on my high-school ride in the 80's.... Scared the crap out of me when it happened.
Imagine if it happened under severe duty apps (heavy towing/loads)? The plates added that additional strength/security. The entire arm was not plated, just the top/bottom F/R sections close to the bushings/U-bolts where the flex/twist would be minimal since that's where they're bolted solid to the mounts/rear end.
If I'm upgrading OE arms, I clean between the seams as much as possible w/a wire brush & use air/water pressure to get the funk out. Then I'll do some short 1-1.5" length stitch welds in the horizontal seams about every 6-8 inches of the length. I also weld the vertical seam @ both the front & rear of the arm. Less weight vs. plating & stronger than OE.