Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

Fixie efficiency

Old 06-06-05, 09:14 AM
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LóFarkas
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Fixie efficiency

I have read at a couple of places that fixies are faster than freewheel bikes... I'm not talking about straight chainline and no derailers. Some say a fixie is more efficient than a similar SS. Is there some flexibility in the ratchet mechanism of a frewheel that sucks up a tiny fraction of the power?
If there was no such loss, it would have made no sense at all for O'Grady to ride a fixie w/ 2 brakes at the Giro prolog, he should have gone for a SS.
So, does anyone have access to lab test results or have an educated guess at least? Are we talking about a fraction a percent or what?
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Old 06-06-05, 09:18 AM
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I think it would have to be the flywheel effect that seemingly increases efficiency.
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Old 06-06-05, 09:31 AM
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Originally Posted by LóFarkas
I have read at a couple of places that fixies are faster than freewheel bikes... I'm not talking about straight chainline and no derailers. Some say a fixie is more efficient than a similar SS. Is there some flexibility in the ratchet mechanism of a frewheel that sucks up a tiny fraction of the power?
If there was no such loss, it would have made no sense at all for O'Grady to ride a fixie w/ 2 brakes at the Giro prolog, he should have gone for a SS.
So, does anyone have access to lab test results or have an educated guess at least? Are we talking about a fraction a percent or what?
maybe because of rules he was forced to ride with 2 brakes?
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Old 06-06-05, 09:38 AM
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Flywheel effect??? Like the drivetrain pushes your foot through the "dead spot"? No way.

Jamey: Ok, maybe you are forced to run 2 brakes, but the question remains: why fixie? Just because he used to be a trackie and likes fixies? That'd be a lame reason... Why not a freewheel ss, that allows you to coast at a sharp turn or if you have to stop due to mechanical failure or whatever. Ok, that prolog might have been totally straight and if you have to stop you are screwed anyway, but the Brithish use fixies on long, curvy TT's as well.
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Old 06-06-05, 10:00 AM
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Originally Posted by LóFarkas
Flywheel effect??? Like the drivetrain pushes your foot through the "dead spot"? No way.

Jamey: Ok, maybe you are forced to run 2 brakes, but the question remains: why fixie? Just because he used to be a trackie and likes fixies? That'd be a lame reason... Why not a freewheel ss, that allows you to coast at a sharp turn or if you have to stop due to mechanical failure or whatever. Ok, that prolog might have been totally straight and if you have to stop you are screwed anyway, but the Brithish use fixies on long, curvy TT's as well.
hmm..i'm not really sure. i see what you are saying and i really don't see any reason for him to ride fixed. i think it might just come down to personal preference in this situation.
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Old 06-06-05, 10:07 AM
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My guess would be that he rode fixed because, like any trackie trying to set a record, he knew he could calculate speed, cadence, ride time, etc. according to his chosen gear. To answer your original question, one would assume that there is some sort of infinitessimal amount of drag created by the pawls and the extra set of bearings in a freewheel that might not be neglible at his level of performance.
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Old 06-06-05, 10:09 AM
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Originally Posted by LóFarkas
Ok, that prolog might have been totally straight and if you have to stop you are screwed anyway, but the Brithish use fixies on long, curvy TT's as well.
they might give it up if somebody tells them its more efficient
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Old 06-06-05, 10:19 AM
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Maybe it was to get people talking about him......

Do something different and people will talk. In the large bike club I am a member of I know a handful of people by name, but it seems everyone knows me by name or as "that guy that rides the fixed gear."

The heck with eating a Snickers and becomming president.....http://www.snickers.com/advertising.asp
Ride a fix gear and be famous.
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Old 06-06-05, 11:01 AM
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because, unless i'm wrong, there are no 14t freewheels... the smallest consumers can get in conventional threading is 15t... to get the same gear ratio, he would need to use a larger chainring that might need drastic modification of the bike
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Old 06-06-05, 11:21 AM
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You can get smaller toothed freewheels. You just can't get them in conventional threading, you have to go with the smaller "metric" threading. Or you go with a freehub and go way down.

I suspect it's everything to do with being able to feel your cadence and maintain a strong rhythm. If you're coasting on a kilo, you've already lost.
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Old 06-06-05, 11:31 AM
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I have read that fixed gear bikes are 2-8% more efficient than a freewheel bike. At the pro cyclist level, the difference in power between athletes is minute. If the course was suitable for a fixed gear bike (flat, steady to no wind and no tight turns), you would have a definate advantage over someone on a geared bike.
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Old 06-06-05, 11:44 AM
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Originally Posted by captsven
I have read that fixed gear bikes are 2-8% more efficient than a freewheel bike. At the pro cyclist level, the difference in power between athletes is minute. If the course was suitable for a fixed gear bike (flat, steady to no wind and no tight turns), you would have a definate advantage over someone on a geared bike.
i think that this is due to minute losses in friction with a crossed chain.. comparing fix vs ss, i think the mechanical losses are much less significant

i agree with bostontrever that it may be a rhythmic thing
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Old 06-06-05, 01:04 PM
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this thread is funnny.. for a bunch of people who mostly prefer fixed over ss to sit around mulling "hmm.. why fixed?" maybe he likes it better.. which makes for a better ride.. they arent machines.. they are people with preferences too.. i know i hated long flats on my road bike but love them on my fixed gear.. i would think just psychologically... cranking a fixed gear on a time trial would be way better then a ss..
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Old 06-06-05, 03:12 PM
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I think international cycling rules are you have to have two brakes, it's a UCI rule. I'm considering entering a local crit in August and I have to keep this in mind because I don't see another bike with gears appearing for me, so I might have to ride it on my Langster. Crit's nice and flat, so I don't see a big problem, actually, I just have to keep both brakes on it if I do that.
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Old 06-06-05, 03:19 PM
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uh, sorry, lilHinault, but you'd be an absolute menace in a crit on a fixie. please do yourself and especially all the other racers a favor and don't even think about it...
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Old 06-06-05, 03:36 PM
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Originally Posted by lilHinault
I think international cycling rules are you have to have two brakes, it's a UCI rule. I'm considering entering a local crit in August and I have to keep this in mind because I don't see another bike with gears appearing for me, so I might have to ride it on my Langster. Crit's nice and flat, so I don't see a big problem, actually, I just have to keep both brakes on it if I do that.
bad idea man. you've got to stop pedaling to make turns in a crit.
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Old 06-06-05, 05:25 PM
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Fixed isn't allowed in UCI crits. UCI/USCF only allows them on the road in time trials.
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Old 06-06-05, 06:23 PM
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I was told that I could not enter with a fixed gear in the local crits.

Time Trials now that is different.
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Old 06-06-05, 06:29 PM
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Originally Posted by jamey
maybe because of rules he was forced to ride with 2 brakes?

or maybe he liked riding the hoods.
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