I am 235 and I put on 1000 miles on my rollers this winter without any problems for my rims.
I put my rollers in a doorway, but I don't have any problems anymore. I could probably put them in the middle of the room and not have any problems, but I still ride in a doorway. I feel more comfortable that way.
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2007 Jamis Ventura Comp
2006 Jamis Explorer 2.0
2000 Specialized Hardrock (bought used)
Swim, Bike, Run and sounds like fun