The design of Shimano freehub style rear hubs make them popular for non racing applications. Here's why we like them.
- Cup and cone (non cartridge bearing) bearings can and will last a lifetime if maintained properly.
- Shimano freehubs, the removeable part that contains the ratchet mechanism, are reliable. They are also replaceable when necessary.
- Bearings are placed wider than most other designs. (see Slim's image below) This reduces bending moment on the axle and also reduces bearing loads caused by lateral loads.
Of course they aren't perfect. Some downsides include:
- Cup and cone bearings require periodic maintenance. And that maintenance requires more finesse than simply removing and replacing a cartridge bearing.
- Heavier than most other designs.
Despite these downside we still prefer these hubs when the mission is not racing or otherwide dependent on ultra light weight. There is one other feature that we appreciate. Most Shimano freehub based rear wheels can be made even more durable with a couple DIY mods. Both changes allow rear wheels to build with less dish. First, if your frame will accept it, rear wheel spacing can be changed to 135mm by simply adding a 5mm spacer between the left locknut and left cone. An even more radical alteration is to find an older 7 speed freehub. This will allow additional spacers to be added to the left side for a wheel with even less dish.