Well, at 240, I snapped an aluminum frame.
ON your crank, I think you need to view a gearchart. You don't use the small chainring to avoid using smaller gears. NOT WISE! If you knew what the gear combos were, you'd see it's not wise to avoid the small ring. If you view the chart, you will notice that the small ring and the 4th tallest cog is about he same gear as a double crank with a 12/25 cassette.
Only thing you did was destroy your equipment by crosschaining for no reason.
...If you use th small chainring and the 21'ish cog, you have a starighter chainline while applying the torque of climbing.
My current frame is a carbon/CF mix. It hasn't snapped yet and I do plenty of climbing (5,000 -10,000 footers)