I've been researching bikes with Alfine drivetrains such as Giant Seek 1, Kona Dr. Fine, Jamis Commuter 4, etc. All of those bikes are hard to find in my area. (To be fair, I think the Giant cannot be found primarily because they're between 2009 and 2010 model years.)

I also run across a lot of nice looking bikes with Nexus drivetrains, but I tend to shy away since I'm worried the Nexus is just a low-cost version of Alfine. Of course, I don't really know. Can anyone explain what the major differences are between these two component groups?

Alfine is the new version of the Nexus. It has better bearings and there is a disc brake version. Nothing wrong with the Nexus hub,the Alfine is just a little nicer.

The major difference is that Alfine can run disk brakes.

There are two versions of the current Nexus hub, the inexpensive one and the "Red Band" deluxe version. Both have had several model number changes and upgrades since originally introduced.

The lower priced version, per Shimano, uses sleeve bearings on the planet gears and has less well finished bearing races. The internals of the deluxe version are supposed to be the same grade as the Alfine hub but the Nexus cannot mount a disc brake.

Here is a link to a Shimano document which lists differences.

https://www.shimano.com/publish/conte...een%20Hubs.pdf

Excellent. Sounds like I should go back and reevaluate bikes with the 8R36 hub. It was the Felt X-City line that was giving me consternation. X-City 1 at $1500MSRP vs. X-City 2 at $900MSRP.

The OP asked a really good question. Shimano has been up front about the many versions of 8-speed hub they have produced, but some bike company marketeers are less than forth-coming about which hub they've spec'd. The discerning cycle consumer has to go see the actual bike and read the model number off the hub to understand what they're getting for their money.

Best,
tcs