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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)

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Old 06-14-07, 12:00 AM   #1
slotmachine
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bouncing in the seat

hey riders...first post, be easy

I am about 5-7 on a 52cm bike, I feel like my seat is high enough but I tend to bounce a little when I approach max speed when I ride. Instead of a fluid cycle its a little choppy and I know its putting a hurt on my speed. Any suggestions??
Bigger arms? higher seat longer stem combo?

-zach
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Old 06-14-07, 12:28 AM   #2
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you have to 'stay a step ahead of the pedals'. this is learning the art of spinning.
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Old 06-14-07, 12:55 AM   #3
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Higher gear ratio. At a high enough RPM, bouncing is inevitable. For me it's like 140 or 150 and I'm done.
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Old 06-14-07, 01:37 AM   #4
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Practice.

Try pulling up on the pedals during the spin, as if trying to spin and raise the bottom bracket at the same time.

Similarly, you can get a little ahead of the pedals by visualizing trying to hit the handlebars with your knees.
You can't do it, but trying to do it activates some of the hip muscles earlier in the spin.

Most of the bounce, if not all of it, comes from continuing to push down on the pedals even after they have started to rise in the back half of the spin.
When we do this, we can think of ourselves as "behind" the spin.

If we can get ahead of the spin, then we will started to pull up on the back side of the spin just a little before the pedal actually begins to rise.

Pulling up on the bottom bracket and imagining hitting the handlebars with our knees will help us get ahead of the spin.

This summer I've geared way down to 59 gear inches (42 X 19) in order to force myself to learn to spin without bouncing.

I get around town pretty fast, and although the downhill portion of my commute has increased by a few minutes, I've taken the same minutes off the return uphill portion, and the total time for my commute remains the same.
Try gearing down and forcing yourself to spin.
Fun.
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Old 06-14-07, 01:48 AM   #5
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Ken, what RPM are you spinning at before you 'spin out'?
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Old 06-14-07, 11:12 AM   #6
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whoa, first things first.

You say that "feel" that you're seat is high enough, but "high" and "properly positioned" are two different things. Off the bat, you're 5' 7" on a 52cm frame. I'm 5' 6" on a 54cm frame, and that's a bike that I've been sized and fitted to. I've held 20+mph paces on my bike with a fluid spin, and have cranked it into the high 20s and low 30s, also with a fluid spin and controlled pedal mashing.

Here are some things to you need to clarify so that you can get better feedback:
1. Is this a new, properly sized bike, or is it used and hopefully, relatively fits kinda OK?
2. Do you know how to properly set your position on a bike (seat height, saddle angle, saddle fore/aft, handlebar stem hieght, angle, length, cleat position), or are you just going with what feels right?
3. How would you desribe your riding style, are you a guy who just rides around for fun, or a seasoned racer who turns fluid circles in his sleep?

Not picking on you (that happens after a few posts), but this is the kind of info needed to better asses how your bike might be affecting your riding, or vice versa, or both.
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Old 06-14-07, 11:29 AM   #7
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slotmachine lots of it is just practice. You don't need to gear up, you just need to get better at spinning and the way to do that is by riding down more hills. I ride a 69" gear and never bounce anymore, even on steep long descents. My hillclimb teammate rides a 65 inch gear, I see him spinning like an insane hamster on the way down (up to 160 rpms) but never bouncing.
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Old 06-14-07, 11:48 AM   #8
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Quote:
Originally Posted by jpearl
you're 5' 7" on a 52cm frame. I'm 5' 6" on a 54cm frame, and that's a bike that I've been sized and fitted to.
and I'm 5'5" on a 49cm frame.

but yes, there are a million and a half ways to look at fit. getting fit and comfy on the bike is step one; step two is learning to spin faster.

for starters, if your saddle is too high or two low, you're already behind the 8 ball.
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Old 06-14-07, 01:03 PM   #9
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The only way to fix that is to ride on golf cart trails!
Would using rollers or a trainer help with developing a good spin?
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Old 06-14-07, 01:11 PM   #10
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Quote:
Originally Posted by Andre
Ken, what RPM are you spinning at before you 'spin out'?
I don't know.
I don't have a computer on my fixed gear bike.

I suspect I don't spin at as high an RPM as more seasoned fixed-gear riders, but I have the impression that my ability to spin at a higher RPM has increased significantly since I have geared waaay down to 59".

I have in the past ridden with 82", and I look forward to seeing how much improvement I have made, when I go back to 82".

Of course, I assume I have improved.

The lead mechanic at a local bike shop says he can spin at 160rpm.

I don't question his truthfullness, but does this seem possible or probable?

Who has a high spin rate they can verify by computer?

How high?
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Old 06-14-07, 01:15 PM   #11
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Quote:
Originally Posted by Ken Cox
but does this seem possible or probable?

Both. Geared low fixed on a steep hill I would not be shocked by numbers in the low 200s. 160 is definitely possible even with a freewheel.
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Old 06-14-07, 01:20 PM   #12
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Use this metronome to visualize 160 rpms KC. As dutret says it's possible and probable.

http://www.metronomeonline.com/
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Old 06-14-07, 01:32 PM   #13
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Quote:
Originally Posted by Ken Cox
I don't know.
I don't have a computer on my fixed gear bike.

I suspect I don't spin at as high an RPM as more seasoned fixed-gear riders, but I have the impression that my ability to spin at a higher RPM has increased significantly since I have geared waaay down to 59".

I have in the past ridden with 82", and I look forward to seeing how much improvement I have made, when I go back to 82".

Of course, I assume I have improved.

The lead mechanic at a local bike shop says he can spin at 160rpm.

I don't question his truthfullness, but does this seem possible or probable?

Who has a high spin rate they can verify by computer?

How high?
I don't have a computer either, I just estimate it. It's not hard to know when you're doing 60 or 120RPM because that's either 1 or 2 rotations per second, respectively. Also, if you have a speedometer and know your speed, you can use that Rabbit program to figure out what RPM you're spinning at for a certain speed on your gear ratio. So I was able to figure out that when I'm bombing the biggest hill in my neighborhood, I'm doing around 140 RPM and 35mph. But there's room for human error, too. I'm pushing around 80GI for the opposite reason you're doing 59, I want to improve power and strength. When you jump back from 59 to 80 you're going to be surprised at how slow you pedal for the same speed...
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Old 06-14-07, 01:36 PM   #14
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i guess at rpms. thinking in terms of two rotations per second is not useful for me, because when i'm riding, having a cadence throws off my ability to guess at the length of a second. and i don't wear a watch.

but having listened to that online metronome, i thought, "woah - that fast, huh?"
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Old 06-14-07, 01:52 PM   #15
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Fastest I've spun putting power in on the flats is 155rpm.

Going down hills where i'm just trying to keep my feet in the pedals i've probably gone faster than that (175-180), but that gets kind of hairy, and even with the gravity assist, i can't sustain it for long.

If you know your speed and gearing, then you know your cadence.

Last edited by fatbat; 06-14-07 at 02:02 PM.
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Old 06-14-07, 01:59 PM   #16
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Quote:
Originally Posted by jpearl
whoa, first things first.

[]You say that "feel" that you're seat is high enough, but "high" and "properly positioned" are two different things. Off the bat, you're 5' 7" on a 52cm frame. I'm 5' 6" on a 54cm frame, and that's a bike that I've been sized and fitted to. I've held 20+mph paces on my bike with a fluid spin, and have cranked it into the high 20s and low 30s, also with a fluid spin and controlled pedal mashing.[/b]

Here are some things to you need to clarify so that you can get better feedback:
1. Is this a new, properly sized bike, or is it used and hopefully, relatively fits kinda OK?
2. Do you know how to properly set your position on a bike (seat height, saddle angle, saddle fore/aft, handlebar stem hieght, angle, length, cleat position), or are you just going with what feels right?
3. How would you desribe your riding style, are you a guy who just rides around for fun, or a seasoned racer who turns fluid circles in his sleep?

Not picking on you (that happens after a few posts), but this is the kind of info needed to better asses how your bike might be affecting your riding, or vice versa, or both.
Seat tube is not a great estimate of proper fit the top tube is a better estimate. Additionally not all geometries are the same and not all companies measure the same.

If soemone is bouncing around in the sadle, the sadle is probably too low.
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Old 06-14-07, 02:05 PM   #17
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I followed mandrel's metronome link and 160 doesn't sound that fast.
But then, I don't know how to transfer that to a bike.
I tried to imagine it, but couldn't get in sync with the metronome.

Quote:
Originally Posted by Andre
When you jump back from 59 to 80 you're going to be surprised at how slow you pedal for the same speed...
Every new gear inch I've tried has had its share of surprises.
Having ridden 82" before, I expect a significant change when I bring my 59" skills to 82".

I had thought of going back up through my available gear inch combinations, all the way to 82", spending perhaps a week at each level.

I can do 59", 65", 69", 73", 75", 78" and 82", meaning, I have the rings and cogs to do it.

Most of all I want to retain my ability to brake going downhill, without skidding.

Previously, I could not effectively brake above 73".

It seemed more of a skill issue than a strength issue.

Maybe I should go straight back to 82".

The speed might scare me.
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Old 06-14-07, 02:40 PM   #18
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Braking downhill without skidding? Do you mean by backpedaling? That sounds like bad news for the old knees... skip stops are the best bet when you're going down a hill brakeless, at least in my experience.
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Old 06-14-07, 02:53 PM   #19
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Judging by the remarks on this thread, the following will probably not be believed, but...

Elite track sprinters can be capable of approaching 300 RPM. They do not do this while racing but while training in very small gears.

Elite track racers in general can usually exceed 200 RPM. This is not considered exceptional.

I know these things as personally observed fact, FWIW, and have touched 215 RPM myself.

The way to do it is to simply do it. You need to make a concerted effort to occasionally spend 10 seconds or so at maximum RPM, and a road bike helps. Engage something silly like the 39x21 and just go for it, making sure that you are fully rested in between each effort. This is a bit rough on the bike, BTW, as you WILL be bouncing on the saddle, and it needs to be done with a firm and secure engagement between the foot and pedal, ie. not sneakers and nylon toe straps.

A few months of x10 efforts a day twice weekly will result in the ability to exceed 200 RPM. If that's important.

<edit> As another poster mentioned, when you exceed your personal ability to spin, you will bounce, and all the bike fitting tips in the world won't help that. My own limit these days is somewhere around 140 RPM, which is pretty poor by "good bike rider" standards, and that's due to nothing more or less than lack of training.

HTH!

Last edited by Six jours; 06-14-07 at 02:58 PM.
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Old 06-14-07, 03:25 PM   #20
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i got to around 225rpm in some gold sprints once...that is hard to sustain for a 1/4 mile even with no restriction on the pedals.

i've thought about throwing a cheap computer on my bike to see what certain cadences feel like and see what my max is, downhill and on flat road.

the guessing by number of pedals per second is pretty inaccurate.
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Old 06-14-07, 03:26 PM   #21
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oh yeah, and backpedaling downhill to control speed is no big deal.
yeah, skid stops work too.
as far as bouncing, i would look at saddle height, i think i had my saddle too high for a bit and it made my spin less smooth.
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Old 06-14-07, 05:49 PM   #22
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I just went for a ride to test what I think I know.

First of all, I don't/can't come anywhere near the 160 on the metronome.

Way below that.

Secondly, at 72" and below, back-pedaling doesn't seem to have any adverse effects on my knees, and I keep getting better at it.
I resist the rising pedal more than I pull up on the descending pedal, and I have lots of body organization techniques involving the hips that really help.

Thirdly, I can believe elite track riders hit impossible-sounding rpm's like 300.

I should put a computer on my fixed gear bike and find out what rate of spin I have.
I hate to put anything on my fixed gear bike, though.
I love its simplicity.
But maybe for a little while.
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Old 06-14-07, 06:09 PM   #23
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Quote:
Originally Posted by Ken Cox
I just went for a ride to test what I think I know.

First of all, I don't/can't come anywhere near the 160 on the metronome.

Way below that.

Secondly, at 72" and below, back-pedaling doesn't seem to have any adverse effects on my knees, and I keep getting better at it.
I resist the rising pedal more than I pull up on the descending pedal, and I have lots of body organization techniques involving the hips that really help.

Thirdly, I can believe elite track riders hit impossible-sounding rpm's like 300.

I should put a computer on my fixed gear bike and find out what rate of spin I have.
I hate to put anything on my fixed gear bike, though.
I love its simplicity.
But maybe for a little while.
Wireless computers are really cheap, the sensors go on with zipties and some of the units themselves mount with just a rubber band. They're minimally intrusive and also very easy to remove, and if you are just using the comp to log distances maximums and averages you can carry the actual unit in your pocket.
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Old 06-14-07, 06:35 PM   #24
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I'm with Ken on this one, in that I hate additional gadgets on my bikes. Occasionally they serve a function so useful that it outweighs the clutter, and I've occasionally used computers, RPM sensors, HR monitors, and powermeters, but almost always take them back off after I've learned what I wanted. Each to his own, of course, but for me the attraction of the FG/SS is its simplicity.
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Old 06-14-07, 07:15 PM   #25
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Quote:
Originally Posted by Ken Cox
Who has a high spin rate they can verify by computer?

How high?
I'll hit 27 mph on a hill I ride daily, and I'm running about 65 gear inches, so that works out to around 142 rpms on the pedals. not a sky high spin but you get an idea.

RPM = (( 160934.4 (S/60) ) / W ) / (C/c)

S = speed in mph
W = wheel circumference in cm (700x23 = 208.7cm)
C = chainring
c = cog

or as a rough estimate, RPM = (mph * 341) / gear inches
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