I'm modifying my CX bike to double as a lightweight tourer. I'm currently running a 1x10 SRAM Force/Rival drivetrain. I'd like to replace my single front chainring with a "mountain double" to utilize the latter's low gearing. My question is whether or not there is a difference between "mountain" and "road" 10 speed drivetrains? Can the same chains be used on both? How about "mountain" chainrings in the front and "road" cassettes in the back? Is the distinction just marketing rubbish or is mountain 10 gear heavier duty?
The distinction is gearing and a weight/durability tradeoff. Spacing and cable pull is the same within brands + speed groupings (eg 10 speed SRAM). You can even mix and match your cassettes, cranksets, and chains between SRAM and Shimano within a speed grouping- just make sure you don't mix and match derailleurs and shifters as the cable pull is different. Note that I left Campagnolo out of the mix- just don't go there.
10 speed Shimano MTB & Road are not compatible. You can however get around this by using a 9 speed shimano MTB derailleurs and SRAM cassettes to get a bigger gear range on a Shimano Road groupset.