1989 Specialized Rockhopper

I used a set of Tiagra components. These components came on my Kona Jake, and have been on a few bikes since as I tinkered and upgraded. Using STI shifters, you need a road front derailleur. Bar end shifters eliminate this problem and save money, but I like STI.

The "stem" is a Velo Orange threaded-to-threadless adapter with a stubby (80mm) Profile Design Aris stem. The VO adapter has a flange that is meant to work with a stem that has a 40mm stack height. The Aris is about 41mm, so it has a bit of a bowl effect, but I can live with it. VO sells matching stems, and Ritchey stems also fit well.

Another potential issue, depending on the age of the mountain bike, is rear spacing. My '89 came with 130mm spacing, so off-the-shelf MTB wheels don't fit and the original freehub wouldn't take an 8/9/10 speed cassette. I could have cold set the frame, but I decided to build custom wheels with Mavic XM 317 rims and Tiagra hubs instead.

If you get an old enough bike, it will have cantilever brakes, which work nicely with road brake levers. On the other hand, if you get a bike with V-brakes, you'll need Travel Agents (unless you swap in cantilever brakes). Mine came with cantilever brakes, but I switched to V-brakes with Travel Agents.

I also replaced the original bottom bracket with a cartridge. The crank, headset, seat post and saddle are still original.