L.swartz Posted July 11, 2019 Share 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?? Edited July 11, 2019 by L.swartz Link to comment Share on other sites More sharing options...
andydude Posted July 11, 2019 Share 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. Link to comment Share on other sites More sharing options...
Long Wheel Base Posted July 12, 2019 Share 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? Link to comment Share on other sites More sharing options...
andydude Posted July 12, 2019 Share 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? Link to comment Share on other sites More sharing options...
Long Wheel Base Posted July 12, 2019 Share 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. Link to comment Share on other sites More sharing options...
Schmorglebot Posted July 12, 2019 Share 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 1 Link to comment Share on other sites More sharing options...
Long Wheel Base Posted July 12, 2019 Share 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? Link to comment Share on other sites More sharing options...
Schmorglebot Posted July 12, 2019 Share 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 Long Wheel Base 1 Link to comment Share on other sites More sharing options...
Schmorglebot Posted July 12, 2019 Share 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 Long Wheel Base 1 Link to comment Share on other sites More sharing options...
L.swartz Posted July 12, 2019 Share Yoh that is insane. Are the cranks shorter? I don't know its a stock rook race 1 fixie... Link to comment Share on other sites More sharing options...
L.swartz Posted July 12, 2019 Share Yoh that is insane. Are the cranks shorter? i just checked my bike pdf and the cranks are 170mm Link to comment Share on other sites More sharing options...
L.swartz Posted July 12, 2019 Share . Edited July 12, 2019 by L.swartz Link to comment Share on other sites More sharing options...
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