Conquent: Without Limits
Conquent: Without Limits
John Bissell's Blog

8 speed is all you need

2010-04-15 12:11:57
Shortcut URL: http://t.conquent.com/fA00

People used to ride and race bikes with only one gear – direct drive, no coasting, no brakes. Then someone invented the Safety Bike (modern bike frame and wheel shape) and there were two gears - if took your wheel off and flipped it the other way round. Then Tullio Campagnolo came up with the quick release and the first derailleur giving us two gears on the same side of the wheel. Pretty soon there were five gears and then the addition of two at the crank set gave us 10 gears, and we were stuck there for really long time. There were some triple crank sets around in the 60’s but they weren’t very good. In the 70’s Sun Tour came up with the Ultra 6 and then the Ultra 7, and a couple of manufacturers came up with some good triples crank sets, though the racers scoffed at those triple crank sets (and still do). In the 90’s 8 speed cog sets became standard, then 9 speed around the turn of the 21st century. Now 10 speed is standard (and Camapnolo and Shimano are introducing 11 soon). That’s ten gears on the rear wheel. If you have a triple crank set that means you have 30 gears. Wow!

But why? We need gears to be able to stay efficient. A human male athlete produces around ˝ horse power. We are most efficient with our feet turning close to 90 revolutions per minute (RPM). We can deviate down to around 80 RPM and up to around 110 RPM and still maintain some level of efficiency, but for an all day thing we would not want to go much below about 85 RPM and not much above about 95 RPM. By increasing the number of gears an a bike, we can get our legs moving at the right RPM no matter the speed.

But at what cost and what benefit. I’ve run a few numbers here. First the benefit. Using a 39-53 double chain wheel and a 12-25 - 8 speed cog set (a very standard racing set up for mountain areas) there is no need to ever have you legs move slower than 87 RPM or faster than 95 RPM. That is right in the range of efficiency. Thus adding gears to 9, 10 or 11 speed cog sets benefits you not at all assuming your range stays between 12-25. Most racers will not expand to a 26 tooth cog, and more often the range is 12-23 or 11-23. If you want to expand the range for a lower gear, you can add a triple chain wheel. Some racers will do this with a 34, 42, 53 tooth chain wheel combination.

Also, if you’re not racing your sensitivity to just the right speed and just the right cadence is less. So for instance a triple crank set with 26, 38, and 52 tooth chain wheels combined with an 8 speed cog set ranging from 12 – 28 teeth will provide ample efficiency from 4 mph to 45 mph. That’s more than enough for a touring bike.

Here’s the cost. The average life span of a good quality 8 speed chain is 10,000 miles. The average lifespan of a good quality 10 speed chin is 1,000 miles. That’s right: the 8 speed chain, because it is thicker, wears 10 times longer. Further, the good quality 8 sped chain costs between $15 and $20, while the 10 speed chain costs $65 - $75.

Further, this benefits Shimano and Campagnolo very much. Both companies have made all of their decent quality 8 speed equipment obsolete. If you break a shift lever, or ne3ed to replace your cog set, you need to upgrade your entire drive train.

My racing bike with eight speed was perfectly serviceable, except that the cog set was worn. Here’s what I bought to replace my cog set: Cog set, crank set, rear wheel, chain, shift/break levers. Eight Speed Cog set $75.00. Drive Train upgrade $2,000.

Some will say that that the upgraded stuff shifts better and is lighter weight. There some truth to this (though not much), but it is not because it is 10 speed. Changes in technology have made shifting generally smoother. Those changed could be applied to 8 speed just as easily as to 10 speed.

This mandate to go to greater and greater number of gears just makes cycling more of an elite sport. There was a time when you could race fairly nicely on what today would be a $500 bike (calculating in today’s dollars). It wasn’t supreme, but it did not keep you out of the race. Today, you need at least and $1,800 bike to try to race, and then you need to put in the maintenance cost.

So Campy and Shimano capture more money from a smaller market, while excluding young riders and expansions into population sectors that just can’t afford it. Maybe a good short term business plan, but not so good for the long term.




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