Tech Tips: BMX Gear Ratios 63

25:9 or do you prefer 28:10, not sure? Brian sorts out Gear Ratios for you.

Credit: VitalBMX

GlennPPMilligan 5/4/2009 3:42 PM

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Several years ago, (late 1980s), I laced up a Sachs 5-speed hub to a BMX rim.
3rd gear was straight through, so I had two gears lower than normal and two gears higher. That was quite a successful experiment, and resulted in a BMX with a pretty high top speed.

I've been thinking of doing it again with my current single-speed BMX, but this time use a Shimano 11-speed hub.
By my calculations, a cadence of 80 in top gear would propel the bike at about 40 kph (24 mph). It would be wild to overtake cyclists on $3000 carbon road bikes with a BMX, heh heh. Trouble is, those 11-speed hubs are very expensive.

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I got 22/8 to see wtf you know. I had 27/10 both are good but hills are easier with the 22/8 I think I will get a 24t sprocket that can go with my primo hub (8t driver) and my demo hub (9t driver)

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not sure what I am running, but I got a KHE sprocket for $10 and dont know what freecoaster to go with it...

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front teeth / back teeth X over all wheel height = roll out. 52-56 inches is a good average roll out. the size of the tire inflated also influences gear ratio. so a 2.125 compared to a 1.8 will affect your pedaling effort.

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maybe. that must be hard.
usually your supposed to have 23; 8
i like to ride 24;8, so its a little harder.
with a freecoaster i like 28-9 though, so i can pedal harder.

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