Truth about clipless pedals.
07-09-13, 03:59 PM
#251
Prefers Cicero
07-09-13, 04:03 PM
#252
Professional Fuss-Budget
07-09-13, 04:04 PM
#253
Senior Member
...
Yes, I understand the subjective sensations in question. I just don't consider them to be accurate.
...
I'm still open to hearing why sprinting would be different. I'm just not seeing it from a biomechanical perspective, and am (obviously) very skeptical of subjective impressions.
...
Yes, I understand the subjective sensations in question. I just don't consider them to be accurate.
...
I'm still open to hearing why sprinting would be different. I'm just not seeing it from a biomechanical perspective, and am (obviously) very skeptical of subjective impressions.
...
It is an objective fact that I do not have the power I normally have when climbing a hill on flats vs. with clipless. It is an objective fact that my foot lifts off the recovering pedal forcing me to lessen the force from my descending foot least I push myself off my bike.
Now then, tell me how my objective facts fit into your model.
__________________
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
07-09-13, 04:05 PM
#254
Senior Member
If you only use "objective data" (the way you define it), I assume you have no point at all to make about cycling conditions outside the parameters of the experiments you cite, right?
__________________
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
07-09-13, 04:08 PM
#255
Professional Fuss-Budget
However, I really can't recall a lot of people who say "I'm switching from platforms to clipless because my foot keeps sliding off the pedals!"
Also, what happens in a 1200 Watt sprint? None of your data even indicates over 600 Watts.
07-09-13, 04:09 PM
#256
Senior Member
I was referring to the trend as power increases, not the shape of the 400W plot. Effective force at 270 degrees is effectively zero at 400W from a minimum of -50N at 100W. The trend appears more or less linear; it leads me to believe you get positive force above 400W for that particular individual rider tested.
__________________
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
07-09-13, 04:09 PM
#257
Descends like a rock
Well....
• Every single graph I've seen, including vector data when standing, indicates that no one actually applies power to the drivetrain on the upstroke. This includes data collected from a variety of average wattages, cadences, inclines, body positions and pedaling styles.
• Every single graph I've seen, including vector data when standing, indicates that no one actually applies power to the drivetrain on the upstroke. This includes data collected from a variety of average wattages, cadences, inclines, body positions and pedaling styles.
I could equally ask you to clarify what would make you expect that the data would be essentially the same. This is personal experience, that in those two conditions, I apply force to the pedals in a very different way than when I am cruising along.
07-09-13, 04:19 PM
#258
Senior Member
07-09-13, 04:26 PM
#259
Senior Member
I don't have any privileged access, nor do I control who studies what.
At this point, all I can say is "wait until pedal-based power meters are commercialized." Granted, most people on BF will not run their own studies with rigorous protocols. But at least you will be able to see what actually happens when you are standing on a climb.
At this point, all I can say is "wait until pedal-based power meters are commercialized." Granted, most people on BF will not run their own studies with rigorous protocols. But at least you will be able to see what actually happens when you are standing on a climb.
07-09-13, 04:28 PM
#260
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
Here's one example of how the steady-state data is relevant to your claim. In post #231 , you're looking at a graph of riders who were instructed to intentionally pull up on the pedals. In doing so, they did reduce the negative forces on the upstroke, but still did not go into positive territory.
07-09-13, 04:49 PM
#261
Senior Member
Sure, the amount of uptorque is small compared with what happens on the downstroke, and may even disappear, but it does exist, based on those graphs, and exists in varying amounts depending on the cadence. Which goes to the heart of people's claims of using uptorque in conditions that seem logical -- hard climbing, for example.
Track cyclists use retention systems because of the very high cadences they require in sprints. Keeping feet on the pedals at those speeds become problematic. But I imagine they use those retention systems to very great effect when starting -- as evidenced by the number of pull-outs that have occurred in competition (on the upstroke).
07-09-13, 05:03 PM
#262
Senior Member
Join Date: Jul 2002
Location: Sacramento, California, USA
Posts: 40,865
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 2952 Post(s)
Liked 3,106 Times
in
1,417 Posts
I think this graphs illustrates perfectly what the proponents have been saying. That low cadence one is the real clincher for me, but it's also notable that for all the other cadences, there is uptorque evident through large chunks of the phase between 180 and 360.
Sure, the amount of uptorque is small compared with what happens on the downstroke, and may even disappear, but it does exist, based on those graphs, and exists in varying amounts depending on the cadence. Which goes to the heart of people's claims of using uptorque in conditions that seem logical -- hard climbing, for example.
Track cyclists use retention systems because of the very high cadences they require in sprints. Keeping feet on the pedals at those speeds become problematic. But I imagine they use those retention systems to very great effect when starting -- as evidenced by the number of pull-outs that have occurred in competition (on the upstroke).
Sure, the amount of uptorque is small compared with what happens on the downstroke, and may even disappear, but it does exist, based on those graphs, and exists in varying amounts depending on the cadence. Which goes to the heart of people's claims of using uptorque in conditions that seem logical -- hard climbing, for example.
Track cyclists use retention systems because of the very high cadences they require in sprints. Keeping feet on the pedals at those speeds become problematic. But I imagine they use those retention systems to very great effect when starting -- as evidenced by the number of pull-outs that have occurred in competition (on the upstroke).
07-09-13, 05:05 PM
#263
Professional Fuss-Budget
Is it the rider position? Cadence? Levels of power output? Anaerobic or max effort?
In the absence of any clear, relevant data, we have to fall back on our own, personal observations.
And also assume that at some point in their careers, Pruitt and/or Burke have done lab tests involving sprints, even if they haven't published the data.
I would like to see the full context of those remarks. Its difficult to imagine they would be including sprints and steep climbs in that.
pp 132 https://books.google.com/books?id=msd...ciency&f=false
I've seen that before, and I agree that these studies prove them wrong when it comes to cruising on a bike.
07-09-13, 05:18 PM
#264
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
Perhaps, although most of the instrumented pedals used to show left and right torque profiles are not portable so it may not be possible to get that data in the field. Sprinting on a trainer is quite different than sprinting on the road.
07-09-13, 05:27 PM
#265
Senior Member
By the way, Ed Burke died in 2002. His research was conducted before power meters were widely available.
He is not alive for his methodology to be challenged.
Shame we don't have Rick Stern still posting here on BFs. He could have provided us with enlightening, albeit taciturn, up-to-date information on this.
He is not alive for his methodology to be challenged.
Shame we don't have Rick Stern still posting here on BFs. He could have provided us with enlightening, albeit taciturn, up-to-date information on this.
07-09-13, 05:28 PM
#266
Senior Member
Nope.... Bad data is bad data.
...
...
__________________
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
07-09-13, 06:44 PM
#267
Prefers Cicero
07-09-13, 07:52 PM
#268
Senior Member
The graphs don't show the vector forces. The torque after 270 on the mashing cadence, does suggest some upward force. Which is still different from saying there is no upward force or torque applied to the crank.
07-09-13, 08:18 PM
#269
bill nyecycles
Join Date: Mar 2013
Location: Houston TX
Posts: 3,328
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 789 Post(s)
Liked 350 Times
in
190 Posts
i don't see how this is possible unless you were lifting your leg purposefully.
because otherwise physics would dictate your foot rides the pedal up as it forces your leg upward because your other foot is forcing the other pedal downward.
and i doubt you were downstroking so hard that the upward force was launching your foot off the pedal.
07-09-13, 08:27 PM
#270
Senior Member
this makes no sense.
i don't see how this is possible unless you were lifting your leg purposefully.
because otherwise physics would dictate your foot rides the pedal up as it forces your leg upward because your other foot is forcing the other pedal downward.
and i doubt you were downstroking so hard that the upward force was launching your foot off the pedal.
i don't see how this is possible unless you were lifting your leg purposefully.
because otherwise physics would dictate your foot rides the pedal up as it forces your leg upward because your other foot is forcing the other pedal downward.
and i doubt you were downstroking so hard that the upward force was launching your foot off the pedal.
__________________
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
07-09-13, 08:54 PM
#271
Prefers Cicero
I thought about this thread as I rode home on my commuter bike with flat, strapless steel cage pedals, in my work loafers. I also tried to observe my normal pedal stroke and I experimented a bit with it.
Most of the time my foot stays horizontal, but I noticed that every once in a while, without really thinking about it or planning it, I would “ankle” on the first part of the upstroke, tipping my foot down about 45 degrees at the bottom of the stroke and leveling it out again halfway up. I was also aware of “pulling” the pedal back and up when I did that. It’s just a habit I seem to have, doing it for two or three cycles and then returning to keeping my foot horizontal. Probably just varying which muscles I use. Of course I’m using pressure on the pedal as I do it, so it’s really a dragging rather than lifting motion.
If I deliberately took one foot off the pedal and tried to pedal as far around the cycle as I could with the other foot, I could get the pedal to about 45 degrees past the bottom (or to 225 degrees if you wish) even with my foot flat, or actually all the way to middle of the upstroke (270) if I ankled. Again this is a dragging effect on the pedal, not “lifting it” as you might if you had foot retention. So you don’t need cleats or straps to get a little bit of upward force on the back part of the pedal circle.
I could also deliberately “pull up” up all the way through the upstroke without losing contact with the pedal, consistent with the notion that pulling up in some cases simply partially unweights the pedal and helps lift your leg, without actually providing an upward force on the pedal.
However at normal easy cruising cadence – maybe 50 rpm, I could easily lift my foot right off the pedal on every pedal upstroke stroke if I wanted to, suggesting that people who choose to pull the pedal upwards with their cleat can do so. Whether they should, or how long they want to do it for, is another matter. When I cranked up the RPMs to what I thought was about 100, I could still lift my foot right off the rising pedal if I tried, but not repetitively, since I couldn’t consistently reconnect to the pedal at that speed, so it would take a lot of coordination to actually assist the pedal in rising on every revolution at high cadences. However, presumably skilled cyclists could do it, or learn to do it at higher cadences than I can manage and up to a certain threshold. Again, whether they should do it, is another matter.
So what did I learn? At low cadences I can lift my unretained foot off the pedal on every upstroke, suggesting I would be pulling the pedal upwards if I were clicked in. You probably can only do that up to certain RPM threshold – probably well below 100 in my case, but who knows what it would be for some pros. You can also “lift” the pedal a little bit even without foot retention, by tilting your foot and dragging the pedal backwards during the first part of the upstroke.
Most of the time my foot stays horizontal, but I noticed that every once in a while, without really thinking about it or planning it, I would “ankle” on the first part of the upstroke, tipping my foot down about 45 degrees at the bottom of the stroke and leveling it out again halfway up. I was also aware of “pulling” the pedal back and up when I did that. It’s just a habit I seem to have, doing it for two or three cycles and then returning to keeping my foot horizontal. Probably just varying which muscles I use. Of course I’m using pressure on the pedal as I do it, so it’s really a dragging rather than lifting motion.
If I deliberately took one foot off the pedal and tried to pedal as far around the cycle as I could with the other foot, I could get the pedal to about 45 degrees past the bottom (or to 225 degrees if you wish) even with my foot flat, or actually all the way to middle of the upstroke (270) if I ankled. Again this is a dragging effect on the pedal, not “lifting it” as you might if you had foot retention. So you don’t need cleats or straps to get a little bit of upward force on the back part of the pedal circle.
I could also deliberately “pull up” up all the way through the upstroke without losing contact with the pedal, consistent with the notion that pulling up in some cases simply partially unweights the pedal and helps lift your leg, without actually providing an upward force on the pedal.
However at normal easy cruising cadence – maybe 50 rpm, I could easily lift my foot right off the pedal on every pedal upstroke stroke if I wanted to, suggesting that people who choose to pull the pedal upwards with their cleat can do so. Whether they should, or how long they want to do it for, is another matter. When I cranked up the RPMs to what I thought was about 100, I could still lift my foot right off the rising pedal if I tried, but not repetitively, since I couldn’t consistently reconnect to the pedal at that speed, so it would take a lot of coordination to actually assist the pedal in rising on every revolution at high cadences. However, presumably skilled cyclists could do it, or learn to do it at higher cadences than I can manage and up to a certain threshold. Again, whether they should do it, is another matter.
So what did I learn? At low cadences I can lift my unretained foot off the pedal on every upstroke, suggesting I would be pulling the pedal upwards if I were clicked in. You probably can only do that up to certain RPM threshold – probably well below 100 in my case, but who knows what it would be for some pros. You can also “lift” the pedal a little bit even without foot retention, by tilting your foot and dragging the pedal backwards during the first part of the upstroke.
Last edited by cooker; 07-09-13 at 08:58 PM.
07-09-13, 09:18 PM
#272
Senior Member
The one thing that hasn't been discussed in the pedal retention debate is centrifugal force. I suspect that it is the reason why pedal retention becomes important at much higher cadences because the higher speed of the foot/leg mass results in a tendency for the foot to fly away from the pedal.
07-09-13, 09:27 PM
#273
Super Moderator
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,843
Bikes: Old Steelies I made, Old Cannondales
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1173 Post(s)
Liked 927 Times
in
612 Posts
Anti-upstroke summary: Some studies show that moderate, steady state riders do not exert upward force. Therefore, no riders, including sprinters or climbers, ever exert upwards force on the pedals either.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
07-09-13, 09:28 PM
#274
Prefers Cicero
The one thing that hasn't been discussed in the pedal retention debate is centrifugal force. I suspect that it is the reason why pedal retention becomes important at much higher cadences because the higher speed of the foot/leg mass results in a tendency for the foot to fly away from the pedal.
07-09-13, 09:38 PM
#275
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
Objective, n=1 data
For normal steady riding I didn't find any noticeable difference. My foot obviously moves around more with platforms and I don't find it as comfortable but I wouldn't have any issue doing a long ride with the platforms. The sprints were, on average, about 200w less with the platforms and the steep hill about 150w less.
One of the most noticeable differences was just starting out from a stop. With the platforms I couldn't go much above 400w but with the clipless I routinely start out briefly around 500-600w and it was very easy to feel the difference in pulling up. Not a big deal but I suspect this is why track sprinters need their feet firmly locked to the pedals.
Results are summarized below:
Last edited by gregf83; 07-10-13 at 11:10 AM.