Originally Posted by
Ridinglurker
Structurally it is a 1.25". That adapter just makes it fit, but not as strong as 2".
Technically true, yet irrelevant to the question asked.
With a single bike rack such as those cited, you're nowhere near the typical 350lb tongue weight rating for a 1.25" rack and the additional capability of a 525lb rated 2" hitch gives zero functional benefit.
A 2" hitch receiver cost almost the same as the 1.25. So I don't see the point in installing a 1.25" receiver.
Also true, yet also irrelevant to the question asked..
OP already has a 1.25" hitch installed per
post #3. Thus it would cost more to replace the existing 1.25" hitch than to use it.