Camilo

I have a similar rack, but made by Yakima. But it has trays and the arm bears down on the top tube like the Swagman OP uses. Frankly, I have never liked that design because of the fussing I have needed to do to keep it from, at best, scratching or at worst, damaging the top tube. I couldn't get the kind that fixes onto the wheels instead of the top tube because at the time, we had bikes with fenders and I couldn't find one that worked with fenders. Since I now have several bikes in the family that really deserve better care, I might sell it and invest in a better one.

All that said, here's what I've learned:

I have put clear frame protecting tape on all my bikes where the arm contacts the top tube. I keep a roll of heavy duty duct tape on hand to put a piece on any other bikes I may have to transport.

I use a piece of pipe insulation, but that wears out fast because it's fairly soft. The padding doesn't negate the need for frame protection (tape) because grit/dust can get under the padding and still scratch the paint.

For bikes with a really angled top tube they make these things: https://www.skicountrysports.com/pro...-DEFAULT-l.jpg

There's a lot of versions, but they're all about the same. I think they're made for hanging carriers, but I've used them for my upright carrier and they keep the pressure off the top tube.

Finally, boy, I've used my rack - again similar to OP's - for many years on rough roads with many bikes, carbonfiber and metal. Other than finish scratching when I don't protect the frame properly, I have never seen any damage to the top tube. It seems strange that it would dent steel unless it's really, really (really, really!) excessively ratcheted downward.

Maybe ratchet it down less and substitute more bulky padding?

Maybe inspect the contact points of the carrier to make sure the original padding is not eroded exposing metal which is then contacting the top tube? I recently noticed that the original hard rubber padding on the upright arms has worn away and one of them has bare metal showing.

Camilo

I've only cold set one rear triangle, 126 to 130 on a very nice, lightweight (Columbus sl) Italian frame and it was really hard to spread it to the point it didn't spring back. Not difficult per se, but took a lot of effort.

Totally agree. See my post above. I'm of course not sure what OP does, but in my experience with that sort of rack, I would think you'd really have to put a lot of pressure to damage any metal top tube, even the most light weight ones.