L.swartz Posted July 11, 2019 Posted July 11, 2019 I'm running a 46/17 ratio at the moment but i max out at 50kmh and can't keep that up very long. There is a 3km race/sprint coming up (buslane3000) and i know i will spin out.I can only afford to change my cog and was wondering what would be a good tooth number? 46/14??
andydude Posted July 11, 2019 Posted July 11, 2019 Go check out https://www.bikecalc.com/speed_at_cadence and put in your own ring and cog. You must be doing 150 rpm to hit 50 km/h on that 46/17! With a 14 cog you will hit 62 km/h at 150 rpm.
Long Wheel Base Posted July 12, 2019 Posted July 12, 2019 Go check out https://www.bikecalc.com/speed_at_cadence and put in your own ring and cog. You must be doing 150 rpm to hit 50 km/h on that 46/17! With a 14 cog you will hit 62 km/h at 150 rpm.Yoh that is insane. Are the cranks shorter?
andydude Posted July 12, 2019 Posted July 12, 2019 Yoh that is insane. Are the cranks shorter?Is crazy right [emoji3] Although he said for a short time only. Crank length shouldn't matter to speed? One revolution is one revolution?
Long Wheel Base Posted July 12, 2019 Posted July 12, 2019 Is crazy right [emoji3] Although he said for a short time only. Crank length shouldn't matter to speed? One revolution is one revolution?Yeah I think so but it's easier to spin that high with a shorter crank? I am just thinking that the distance covered by your foot with a shorter crank is less. What I was thinking is it would be easier to achieve that high cadence with a shorter crank.
Schmorglebot Posted July 12, 2019 Posted July 12, 2019 Yeah I think so but it's easier to spin that high with a shorter crank? I am just thinking that the distance covered by your foot with a shorter crank is less. What I was thinking is it would be easier to achieve that high cadence with a shorter crank. It's true, the same foot speed will result in a higher RPM as crank length decreases. 165mm for the win!
Long Wheel Base Posted July 12, 2019 Posted July 12, 2019 It's true, the same foot speed will result in a higher RPM as crank length decreases. 165mm for the win!So on track bikes, do they generally have shorter cranks? Is 165mm the common length?
Schmorglebot Posted July 12, 2019 Posted July 12, 2019 So on track bikes, do they generally have shorter cranks? Is 165mm the common length?165mm is pretty common for track and crit racing. It helps with cornering in and makes it harder to damage a beautiful wooden velodrome surface
Schmorglebot Posted July 12, 2019 Posted July 12, 2019 I use 165 on my road bike though. I'm a short guy so it's like an average height bloke using a 172.5, relatively speaking
L.swartz Posted July 12, 2019 Author Posted July 12, 2019 Yoh that is insane. Are the cranks shorter? I don't know its a stock rook race 1 fixie...
L.swartz Posted July 12, 2019 Author Posted July 12, 2019 Yoh that is insane. Are the cranks shorter? i just checked my bike pdf and the cranks are 170mm
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