Inside Internal Gears

31 Mar

Hub-gear systems, speed ratios, derrailleurs, gear inches…  What’s this mechanical confusion  all about?  Moe Saleh  from  Uptown bikes, a Chicago bike building group,  took me through the mechanics and I finally made sense of this madness.   

 Much as with beta and VHS there was a great battle waged in the cycling world at one point.  On one side you have derailleurs, we all know about derailleurs right?   They have their virtues but most of the time you just end up cursing at them.  On the other side there is the long forgotten internal geared hub.   Unfortunately for the internal geared hub, the derailleur won out during the bike boom of the 1970’s.   The parts were easier to manufacture and mass produce, which translates to good for business, bad for us! 

 At this point I’d like to pause and make sure everyone is keeping up with the me.   Most bicycles today have some sort of gearing mechanism.  This comes in the form of cogs on the hub of a bicycle’s rear wheel and chain rings on the cranks (cranks are the pieces your pedals attach to).   Now of course we all know there’s a chain involved somewhere in the middle of all this.  With this type of system the chain is acted upon by a mechanism called a derailleur.  

 The derailleur, using cable and spring tension, is responsible for moving the chain from one set of gears to the other.  It also controls chain tension and alignment.   Why are these gears important I asked Moe?   Much in the same way a car’s transmission uses a system of gears to translate power from the engine to rotation of the wheels, the gears on a bike take the power of your pedaling and distribute that in a particular way to the wheels.   Therefore lower gear ratios require less force to be exerted by the rider but do not yield a high top speed, thus making them ideal for hill climbing.   Higher ratios require considerably more force but yield a higher top speed and once achieved make it easier to maintain that speed, thus making them ideal for flat open terrain.   So far so good!

  Internal geared hubs and cranks, however, achieve the same results but with a smaller range of gear inches.  That range is the bikes ability to go from a vertical climb to a dead sprint on a straight away.   Many would vouch for the derailleur pronouncing it to be a marvelous invention  and that it certainly has its place in the bike world.   Uphill climbs on a mountain bike would be hell without them and racers would never be able to go as fast as they do.  But lets say your just a run of the mill commuter, like myself.   What the internal geared hub offers is a clean hassle free system that accomplishes everything one would need for say a 20 – 30 even 40 km daily commutes with less hassle and maintenance.  

 The internal hub doesn’t lose cable tension, it doesn’t get caked with grease or filth from the street, it doesn’t get bent or STOP WORKING COMPLETELY if you happen to fall over.   In short it’s got your back, it’s truly a good friend.  SO let’s be a friend to it.   Spend your money wisely.   With what’s available for internal geared systems today you could potentially have a set up that’s completely comparable to anything using derailleurs, with the only major difference  being money.

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One Response to “Inside Internal Gears”

  1. Commuterjohn March 31, 2011 at 5:01 pm #

    Hi,
    I used to you have a few bikes back in the 70′s that had Sturmey Archer 3 speed hubs on them.
    They were good in their own way, very little maintenance just a short chain connecting the hub to the gear cable that you made the adjustments on.
    They were never anywhere as god as the selection of gears available on a derailleurs gear system and compared to my 28 speed system now seem pretty hopeless unless you live on the near flat.
    Having said that though I have read of internal hubs with an 8 speed gear box on them, that would definateley be worthwhile looking at and could be a future bike for me just for commuting possibly.
    The big bonus with the internal hub is you can change gear while stationary, so when you have to make a sudden stop in high gear it’s no problem to just drop down to low and restart with out moving an inch.

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