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Hub gears

Hub gears have gone through all the highs and lows of fashion during the last few decades. There was a time when they were the only sensible choice for town bikes, propelling deliveries, shoppers and tourers alike. The unquestioned favourite choice was the Sturmey Archer three-speed hub, which could be relied upon to work fine for years under a regime of neglect and would last for decades if an occasional teaspoon of 3-in-1 was poured into the oil port on the hub.

Each one was stamped with the month and year of manufacture and it’s not uncommon to come across hubs from the 1930s still happily chugging along. But with mountain bikes, emerged a desire for more and more gears and suddenly bikes with only three fell out of favour. Bikes with a plethora of close ratios made the big gaps between three seem clunky. Sturmey Archer, based in Nottingham, upped and sold all its machinery to the Far East and it seemed like hub gears were history.

But all was not lost. Some aspects of hub gears are just too attractive to ignore, especially for around town. Having a single chainring at the front makes it easy to fit an effective chainguard, reducing the amount of chain oil on your clothes. The city is also a particularly harsh environment for exposed gears, which tend to pick up all the nasty chemicals that get spat out of the back of cars in traffic and use them as a grinding paste, reducing expensive derailleur components to waste within a couple of thousand miles. Derailleurs also have plenty of delicate dangly bits, which don’t respond well to being tangled up in big piles with other bicycles. So there are a lot of good arguments for tucking the complicated gear mechanism away inside the hub.

Hub gears - 1

There is also a spectacularly bad argument for using hub gears, which is that they don’t need any maintenance. While it may be true that they need a lot less attention than derailleur bikes, it’s expensive to completely ignore them. Most damage is done when they get ridden around out of adjustment. The internal gear mechanism is made up of lots of tiny cogs and pawls. When these are all correctly aligned, they wear very slowly, but slight misalignments can cause rapid wear. This is where the problems start – as they wear, the cogs generate lots of tiny flakes of metal. Since the hub is enclosed, these have nowhere to escape to, and so travel around the internal mechanism, wearing away everything they come across. However, adjusting your hub to run smoothly has been made very simple and can usually be done with no tools at all. The most important thing is to be alert to possible problems. If your gears start to feel sluggish, don’t change as quickly as you’re used to or start changing randomly as you’re riding along, check the adjustment straight away.

There are other simple procedures that can also be carried out without special tools. Changing the sprocket is not nearly as complicated as it looks. It’s a good idea to change the sprocket every time you change the chain, since they wear together and putting a new chain on an old sprocket will wear your nice new chain very quickly.

Another good reason to change the sprocket on your hub is to change your range of gears. You can’t change the gap between each gear as this is determined by the internal mechanism, but you can change where the range starts and finishes. Changing your sprocket for a slightly larger one will make all the gears slightly lower. The gaps will remain the same, but each one will be easier.

Hub gears - 2

Changing the size of the sprockets also affects chain length. Minor changes – say one tooth more or less – can usually be accommodated by shifting the rear wheel backwards or forwards in its dropout (since you don’t have a derailleur to take up the slack, this is the only way of ensuring the correct chain tension). If you’re fitting a smaller sprocket, you can shorten your chain slightly. A larger sprocket will require a longer chain. It’s usually more successful to fit a complete new chain than to try to add links from another chain as the uneven amount of wear in the links means the chain will be unlikely to mesh smoothly with the sprocket or chainrings. Luckily, decent chains for hub gear bikes are around half the price of a similar-quality derailleur chain and last twice as long. They don’t have to move sideways across a cassette or chainset and always run in a straight line from sprocket to chainring.

Hub gears are also an excellent choice for folding bikes with small wheels because the absence of a derailleur means there’s less to get caught up when you’re collapsing or reassembling your machine. Keeping all the oily messy gear parts inside the hub makes you a more popular commuter too, being less likely to leave black stripes on other people’s luggage in crowded train compartments. As well as the more traditional three-speeds, seven- and eight-speed versions have a wide enough range of gearing to get you up and down most hills. A 14-speed hub, by Rohloff, gives as wide a range as you’d get with a triple chainset, with smooth, close gaps between each gear.

“Some aspects of hub gears are just too attractive to ignore”

Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES
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