Introductions - kill the noob
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09-26-07, 02:05 PM
please let me live:
If my bike is in a certain gear, let's say 42/16, with a derailleur, would it feel the same if it is a single gear bike on 42/16?
wat is the most common gear for single-speed roadbikes.
You might want to do a search in the SS/FG forum. There have been a million threads about gear ratios. But to answer your question: In my experience, it feels like a gear faster. It's the efficiency of a single gear with a short chain that doesn't have to loop through a derailleur, I think.
09-26-07, 03:31 PM
not to derail the thread and repeat some others, but does having a long chain really affect the gearing?
take this to it's extreme logical end conclusion--say the chain was run thru all kinds of derailleurs, so that the chain is 100 feet long. if the tension on the chain is the same (this could be the reason, but i'm not sure, since the derailleurs would all have some give in them...) as it is with one, then would the ratio be different?
i'm not seeing it...
again, i apologize for hijacking the thread, and if there's a similar discussion happening/having happene somewhere else, please direct me there...
Old Dirt Hill
09-26-07, 03:34 PM
take this to it's extreme logical end conclusion--say the chain was run thru all kinds of derailleurs, so that the chain is 100 feet long.
I have no idea, but I want to see this. I'm serious, it would be cool to watch.
09-26-07, 03:36 PM
No, the gearing is not effected at all. That stays the same, what does change is the weight of the components and the slack in the rear derailer. The slack can lend itself to some pogoing of the bottom loop of the chain under pedaling pressure. Nothing too technical about it but imagine that tight single speed chain zipping around nearly motion less in its rotation. Translates into more efficient travel of the chain. I suppose there may be some friction through the rear derailer but good grease can fix that pretty fast.
09-26-07, 07:59 PM
Now that you know that secret, we will have to kill you.
I've been told that I can probably head up the hills on a SS/FG pretty well even without multiple gears if my legs are strong enough because of the greater efficiency.
I haven't tried it though. There's some big hills where I live.
Welcome to BF!
09-26-07, 10:22 PM
wait, the slack in the chain is between the drive chainwheel (sprocket) and the driven chainwheel (freewheel). the distance of the chain where the tension is stays the same no matter how much slack is in the bottom of the system...if the rear derailleur's springs/pulleys were between the freewheel and the sprocket (after the freewheel, not before), then when you torqued on the cranks, the slack/spring would mean that you'd pull against the pulley/spring, and not the freewheel/wheel.
i think the gearing should be the same, if the chainwheels are the same, regardless of number of derailleurs.
I'm not an engineer, just a bike rider, but it feels faster on a fixed gear.
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