The best is the Rohloff.
This Velo Vision Review/Comparison from March 2008 of Nuvinci, Rohloff, Nexus Alfine 8 and SRAM iMotion 9 Geared Hubs has some useful information: :http://www.velovision.com/mag/issue29/vv29hubgears.pdf
ThereÃ¢â‚¬â„¢s a common link between the bikes weÃ¢â‚¬â„¢ve reviewed so far this issue: they all use internal hub gears Ã¢â‚¬â€œ and not just any hub gears, but the newest and latest from Shimano, Rohloff and NuVinci. As IÃ¢â‚¬â„¢d also fitted the new SRAM 9-speed to my town bike, the stage was set for a four-way shoot-out.
Yedal likes his Nuvinci.
The Rohloff and Nuvinci have the highest torque rating. The SRAM Cargo 5 is rated for Tandem and Pedicab use.
Gary has a friend who builds cruisers with Eteks. Gary posted the following:
I'm sure the Nexus hubs can handle the power. There's a guy with a bike shop down in San Diego (Rusty Spokes, in Pacific Beach...) who custom builds chopper-style motor bikes, using Etek and Mars motors. He uses these same Nexus 3-speed hubs with these beasts, and they have worked flawlessly, even pumping 15 hp through them. Instead of chain, hoever, his bikes are belt driven, using regular toothless v-belts. There's a little bit of "slippage" when starting out, which is like a clutch. Works great, he says, and these things can hit close to 60 in just 2nd gear. Anyway, he's never had a single problem with any of the Nexus hubs.
I sent the owner of Rusty Spokes an email about the Nexus 8. He said he has never had any problems with the Nexus 3 or Nexus 7. He has never used the Nexus 8 but thinks it would be the same. BTW in my email to the owner of RS he seemed offended
when I mistakenly stated that Gary said his bikes topped out at around 50 mph in 1st.
Gary posted someplace the opinion based on reviews by DH Mtn bikers the Nexus 8 is stronger than the Nexus 3.
Some useful information here:http://endless-sphere.com/forums/viewtopic.php?f=28&t=15216
Pay attention to this and the following discussion: