Bike radar says Thomson says it’s ok. . .
http://www.bikeradar.com/gear/category/components/stem/product/review-thomson-x2-road-stem-32438
and a couple reviews on CRC are from XC riders.
only diff between it and x4 is faceplate, I believe — narrower and only two bolt.
lighter and lower stack height than x4.
What say you?

It will be fine, its a Thomson stem!

I had one on my road bike, the only issue was the bars sometimes slipped. I didnt want to tighten the bolts any further as I was using carbon bars.

On a road bike you tend to have a bit more weight/leverage on the bars when on the hoods, but using flat/rise xc bars should be ok.

that’s my worry, though — the bar slipping. I use a wide carbon bar with 17 deg bend.
I’ve twice used salsa stems with two-bolt clamps, tho, and they were fine.

I use one on my CX bike. It has survived many off road trails without problems.

No issue with bar rotating, I probably fitted with a torque wrench, but can’t remember!

I had one on my old CX bike and had no issues with it.

I run road stems off road no problem.

nice. . .