Rub-a-Dub Hub

Rub-a Dub Hub

Bicycle.  A simple word, meaning two cycles.  Frame, group set, saddle, handle bars.  All well and good, but rather pointless if there is not a pair wheels in line with each other, and both able to turn freely.

The wheel is arguably one of the greatest inventions ever.  Chariots, windmill wooden peg gears, clockwork mechanisms, rail rolling stock, gyroscopes, and the space station from 2001.  All use the wheel.  Even the steel castors that tea trolleys are pushed around on.  But in terms of technology and attention to design detail you would be hard pressed to beat the modern derailleur hub.

The first rear derailleur hubs had the cassette (typically just a few sprockets) screwed on to the hub as a separate unit.  One of the first popular units was the Bayliss hub, an example is shown here from Dave Moulton's site.  This design was introduced in 1938.

One might argue that hub gears are technically more advanced than current derailleur systems, but they have their limitations.  Take a look at this exploded view of a typical Sturmey-Archer 3-speed hub unit.

There is a lot of iron packed into that space, and most of them are moving parts.  Which is a good time to remember a good rule of thumb - the more moving parts there are, the more this is to go wrong.

Internal hub gears are heavy, have a much lower effective range of gearing ratio, with fewer gears to choose from (even with the modern Sturmey-Archer hubs that give up to eight gears across a claimed range of 325% from below to above direct drive, they cannot compare to the Campagnolo 11-gear cassette), and need a lot of maintenance to keep the gears from seizing.  So, they remain the preserve of city cruisers and tourers.

The freewheel system allowed the installation of the cassette as a unit, and is still used on many cheaper BMX and single-speed bike hubs. A half-way step is the freehub system with open bearings, used on mountain bikes.  Personally, I loath this system, as the bearings have to be individually placed each time the cassette is removed, for example replacing spokes.  Grease, tweezers, and finding the last dropped bearing.

Shimano and Campagnolo independantly developed a freehub system, although the name freehub is copyrighted by Shimano.  The difference between freewheel and freehub systems in best shown in this diagram.

The freehub bearings are enclosed beneath the ratcheted splines.  The cassette slides onto the splines and are locked into place with a single lockring, no bearings in sight.  In terms of maintenance and simplicity of design, it is ideal.

For my weight and riding style, I have found that 28 spokes is a good minimum build. Several years ago my brother-in-law gave me a Shimano wheelset, both wheels laced with 16 aero spokes.  The front is still performing perfectly, but the rear popped a spoke every 300 km.  A 20-spoke build lasted until the spokes pulled through the rim holes, and a 24h build lasted a few thousand km, but I retired it when hairline cracks appeared around the eyelets.  The 28h build I am currently using is flawless, and has given me over 2600 km without needing any truing. I built it using a Novatec F162SB 28h hub, laced with round spokes to a DT swiss 28h  RR415  rim.

Also of issue are the skewers.  Once upon a time all bikes were secured by an axle that was simply a long bolt.  Many cheap department-store bikes still have wheels secured by a bolt.  If you are in a race and have to swap a wheel or tyre, you really don't want to be mucking around with a spanner.  Wikipedia have a good summary of the quick-release history, from its invention in 1927 by Tullio Campagnolo onwards.  

And now to the market.  First off, if I were to buy skewers separately, I would be looking at about NZ$10 each.  I had been planning on repeating the current rear build but using aero spokes, but the Novatec hubs cost US$70 each. A deal on eBay offered a pair of gold novatecs (20/28h) with skewers for NZ$112, indicating that a bundle would be a better deal.  Scouring the net, there are few affordable 28h Shimano-compatible rear hubs, but the deal came via Wiggle.  For a grand total of NZ$133.99 I acquired a boxed pair of Miche 28h hubs with Shimano freehub, and matched Miche skewers.  Is this a good deal?  I like to think so.  Miche are an Italian component manufacturer with over 70 years experience.  The hubs are forged aluminium, use sealed bearings, are compatible with the Shimano 10-speed cassettes, and weigh 433 grams for the pair.

A touch of Italian style for the ride, and the one box takes care of both wheels, leaving the rims next, and then I can calculate the right spoke lengths for the build,