I'm planning a XC/bikepacking build, and considering a belt drive, and looking to answer a couple questions.

The most recent reviews of Gates belt system performance are from 2014, and none really address two main concerns for me:

First: how does it perform in mud and other rough riding for MTB? I'm aware that dry conditions make it squeak and alignment is critical, but no one really talks much about its performance in muddy conditions. Does it really shed mud as well as Gates advertises? Does the advertised belt lifespan really long enough to justify the extra cost?

Second: A frame split seems like it might cause frame integrity issues over time, especially for MTB. I'm not an engineer so I dunno how to answer this for myself. Has anyone experiences stability issues like frame flex/split breakage/damage?

I've been riding a Gates system on my commuter bikes for over a year now. I rode during winter, and can at least offer that the belt and the IGH hub required none of the cleaning that I'd have to invest in a chain-driven bike in winter conditions.

Whereas my friend who rode his chain-driven bike this past winter had to replace his chain and cassette because he failed to stay on top of keeping things clean.

No issues so far. However, I'm mainly on pavement with my commuter bikes. Sometimes I venture off road, but almost always we're talking smooth off-road. I'm not rattling over roots and rocks with my commuter. Think packed sand. Smooth stuff.

How much mud do you plan to ride through? Sometimes I experience belt slippage when standing on my pedals to power through sand and mud puddles, and sometimes going up steep hills. Increasing the belt tension has helped some, and I have a CDX belt that I plan to swap in that I hope will help even more.

Thanks for your help, that does clear it up some for me. I should have clarified that I'm comparing a belt drive to a SS chain setup rather than a derailleur and the chainline wear/issues associated with that. The decision right now is: Rohloff and chain, or Rohloff and belt.

Admittedly I don't plan to look for mud pits, but this is to be an offroad touring/fun bike, building to things like the Great Divide race in 2018. It'll be offroad a lot and riding a lot of rough terrain.

Hard for me to imagine the rough terrain affecting the belt. I'd probably worry more about the hub.

Gates offers two lines of belt drive systems. I'd get the CDX high-performance parts for your application. Everything is compatible, but the CDX has, for example, steel rear sprockets versus the mixed plastic and steel on the other line. You probably know all that already.

Thanks for the suggestion; I'll probably go that way.