Single-speed mountain bikes are a fun and challenging change from normal geared bikes, but the lack of gears is really frustrating on flats. Going uphill is hard as expected, and going downhill you can coast fast, but on the flats you spin your pedals and go nowhere.

I decided to add an internally geared 3-speed hub to my single-speed. I thought I might be able to keep the clean, quiet, and solid feel of the single-speed, but get a bigger gear for the flats.

I started with a 2007 Redline Monocog Flight 29er single-speed. This cost around $800 and was purchased in early 2008.  It came with a 32 tooth chainring and 20 tooth rear cog for a 1.60 gear ratio.  That 32x20 gearing with the 29" wheels is probably similar to 32x22 on a 26" bike.  The photo on the right below shows the original rear wheel.

The hub I chose for this bike is the Shimano Nexus Inter-3 for $125.  This has an overall gear range of 186% and a stated weight of 945 grams (2.1 pounds).  A normal good rear mountain bike hub weighs 300-350 grams, so the Inter-3 adds at least 600 grams (1.3 pounds).  This hub works with disk brakes.

The hub does not include ...