I recently posted above:
Originally Posted by
Jim from Boston
…My beater is a good quality aluminum
Specialized Diverge, and I bought it as a good-riding beater that I would nonetheless subject to the elements, without the distress of messing up my high end Specialized S-Works. 
Originally Posted by
CliffordK
I suppose it depends a bit on the cost of the CF bike. I do more errands than commuting, but have ridden most of my bikes, including locking them (with a Kryptonite NY lock).
But, like you, I do like to hide the CF bikes away on wet rainy days. Still, if it was relatively inexpensive, I might consider it.
A few years ago I was lucky enough to find a good deal on an older Titanium Litespeed MTB frame which I put road tires on for a winter bike. The frame itself was indestructable, and the build was cheap enough that I didn't worry about it too much.
Of course, going with high-end components, and one gets more complex stuff (brifters), but also more stainless and titanium.
Originally Posted by
Darth Lefty
Frame material was not a deciding factor in my last commuter/MTB buy. The bike that had the features I wanted and was in-stock at a good value was aluminum.
It gets locked up just the same as it would if it were carbon fiber.
For my choice of an Aluminum Diverge as a beater [in the above photo of my indoor storage], frame material was a surrogate for price, about $1500 vs a few thousand for carbon fiber.
