Singlespeed & Fixed Gear - 144 BCD versus smaller
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08-04-07, 03:34 PM
Most track cranks are 144mm, but all the way down to 130mm seems pretty common. Maybe you have more options for tooth count in a larger size?? Still, you could achieve the same gearing with 130mm/49T that most people would want. Smaller would be lighter and possibly shorter chain also... So why is 144 far and away the most common?
08-04-07, 03:35 PM
it justs a different holes pattern..wont effect gearinches. Just think of it as a car wheels bolt pattern.
So why is 144 far and away the most common?
144 bcd is the old Campagnolo standard from the early-60's through the mid-80's. Many companies copied this and many companies, especially Japanese ones, still use old Campy sizes, specs and even old molds. Take the MKS Sylvan pedals for example.
You can get the same gearing with the same tooth count, but it's easier to find lower tooth sizes in 130bcd. And I suppose the same tooth size in 144bcd would be negligibly stiffer than 130 or 135 due to the bigger 'spider'.
08-05-07, 08:00 AM
Larger BCD means less stress on the chainring since the spider extends farther, so you get less chainring flex. If you're built like Nelson Vails you want the largest BCD that'll take the smallest chainring you might use. For mere mortals, that's not much of an issue.
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