We bent a rim on the Oregon BDR bad enough that it wouldn’t hold air last summer. There was next to nothing near us so we tried to straighten the rim. All we could find was a rock and a cow bone, which surprisingly held up to repeated smashing. So our method was - Step 1; support and hit the rim as hard as you can. Step 2; give up and install a tube. It was worth a shot, but no way that rim was going anywhere without a hydraulic press.