What is the maximum input torque on Sturmey-Archer internally geared hubs? What is the maximum input torque that can be sustained by sturmey archers internally geared hubs.  The website is surprisingly short on info about this.

I'm specifically interested in the hybrid gearing hubs that allow fitting a 9 speed cassette onto a 3 speed IGH.  But I expect the internals of all the 3 speed hubs are the same. http://www.sturmey-archer.com/en/products/detail/cs-rf3-silver

The website mentions a maximum sprocket size of 34 teeth, but without the minimum chainring size that's rather meaningless.

Thanks
A pro cyclist putting out 1.4 kWatt at 60rpm at the starting sprint has a torque of almost 2000 lb-in or 222 N-m. 

A recreational bicyclist may be normally only be capable of just 1/10th that but even an out of shape Clydesdale (heavy but strong rider) just getting off to a start on a hill may momentarily hit that level. If they weighed 200kg but jumped on the pedal and momentarily put 800 newtons of force on a 170mm crank, that’s 136 n-m, or still a lot of torque. 

If I was an engineer, I’d want to make sure that my components could handle that level peak on an occasional basis. If you’re really worried, get a Rohloff as they’re really well designed.