First attempt with SPD's today in 30 mins
Comments
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Kubase wrote:When I bought my 5:10s the bloke in the shop told me that SPDs were 37% more efficient, and that he would beat me in any climb if I was using flats no matter how fit I was, despite him being 41. I think this is indicative of the only real problem, which is people new to the sport being pushed into a certain direction when pedal type is such a personal thing.
Well that's clearly bo¦¦ocks! what if you were 50% fitter than him?!
And yes I agree, I'm in the 'try them and see' camp.0 -
Is English your first language cgarossi?0
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Experiments done by real scientist ahve been done adn they support Yee and myself, why don;t you give up as yee has knocked you down again and again yikes see..
And indeed bails, you can pull up but go read teh scooby explanation by yee it was actually a realy nice way of explaining a basic concept that can be really awkward to envisage in this system.
I'm following yee and bailing on this thread anyways now as it gets frustraing trying to explain physics people ona forum format.. have fun and don't fall off clipped in muhahaha0 -
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Realman, do this experiment.
Get on the bike, and clip in one side. Place the crank down, standing on it. Now pull up and pedal.0 -
Thewaylander wrote:Experiments done by real scientist ahve been done adn they support Yee and myself, why don;t you give up as yee has knocked you down again and again yikes see..
And indeed bails, you can pull up but go read teh scooby explanation by yee it was actually a realy nice way of explaining a basic concept that can be really awkward to envisage in this system.
Yeah, it was really hard to recover from the cartoon reference. Real scientists? Have you met these scientists?supersonic wrote:Realman, do this experiment.
Get on the bike, and clip in one side. Place the crank down. Now pull up and pedal.
Yeah, you start to go forwards. I'm waiting for the punch line.0 -
He's not backing down. May as well give him the delusion that he's won an internet argument.
Which will be the first in history I suspect.
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Realman, go and do it. Compare to starting pushing down with the opposite pedal up.
And if you don't start posting more constructively and with a bit of respect for people you will get a warning as I am sick of your attitude.0 -
Thewaylander wrote:Experiments done by real scientist ahve been done adn they support Yee and myself, why don;t you give up as yee has knocked you down again and again yikes see..
A genuine question here - can you link to any of them? I asked about what the conditions of those experiments were earlier and for those who are actually interested in the physics of this it would be nice to actually read up on it a bit.0 -
The scooby doo reference doesnt make sense to me. They're trying to pull a door open, but they pull the handle whilst pushing the rest of the door with their feet right? So they'd pull the door handle off. I get that. But relating that to pedals suggests that you're pushing down with both feet at the same time.
But I think a revolving door is more appropriate as an example. Imagine a revolving door, with the right hand side (centre to 3 o clock position) being the side you need to enter to get through. You could just push with one arm on the right hand side of the door (flats) or you could push the right hand side with your right hand, whilst pulling a handle on the left hand side (centre to 9 o clock) of the door (after punching a hole so you can reach through
). That way you rotate the door by pushing AND pulling at the same time. 0 -
supersonic wrote:Realman, go and do it. Compare to starting pushing down with the opposite pedal up.
And if you don't start posting more constructively and with a bit of respect for people you will get a warning as I am sick of your attitude.
Much apologies, but I at least have refrained from resorting to nothing but insults.
Sitting down, there's not a whole lot of difference between one half pedal turn, upstroke or down stroke. This is probably because on the up stroke, all your muscle is being put into creating the force. You have the saddle and the handlebars to hold yourself against, and as we all know, you can exert more force with one leg then your bodyweight can do under the acceleration due to gravity (try doing a one legged squat - its easy).
This might mean that you can actually accelerate quicker using upstrokes rather then down strokes, when sitting down. I'm not too sure though.
Standing up you really need both feet acting together to provide a reliable upstroke and down stroke. But like we've said before, its much better to apply force from your muscles and your weight, rather then just your weight.0 -
That's better
We need to try and get back to some thoughtful discussion.
There is a definite difference between sitting and standing and how we use our legs. You cannot pull up on the pedals without an equal downward force on the bike to counter it, and while sitting you can indeed start to pedal in the one leg scenario [and possibly standing with the bars to aid].
I would argue that given we accelerate with higher figures when standing then the maximum torque we can produce is during the down stroke when the pedal is fully weighted.
I think as many have said it is what you prefer and getting the most out of them. You can pedal badly with both if your technique is poor.0 -
supersonic wrote:There is a definite difference between sitting and standing and how we use our legs. You cannot pull up on the pedals without an equal downward force on the bike to counter it, and while sitting you can indeed start to pedal in the one leg scenario [and possibly standing with the bars to aid].
I would argue that given we accelerate with higher figures when standing then the maximum torque we can produce is during the down stroke when the pedal is fully weighted.
Of course, what I think a lot of people don't understand is that the equal downward force goes on top of your weight on the pedal involved in the down stroke.
So when you put all your weight into a down stroke on one pedal, the force on the pedal is your mass x gravity.
Apply an upstroke to the other pedal, and the force on both pedals increases by the amount you can make your muscles apply.
As I've said, for about the 5th time.0 -
It doesn't though, not when you are fully standing on the pedals. As you think you are pulling up, you are actually pushing down on the opposite pedal.
You cannot apply more force than your weight when standing on the pedals.0 -
and the force on both pedals increases by the amount you can make your muscles apply.
Wrong!
So wrong it makes me want to reach out and batter you around the head!
Any force you apply on the upward pedal is removed from the downward force, since they are both connected via the axle.0 -
Yes you can. If we go back to my earlier thought experiment.RealMan wrote:Go put one foot on a set of scales. Put the other foot under a table or low shelf, and push it up with your foot. Suddenly the scales reading increases, plus you have the force on the shelf/table.
Maybe that's where people are getting confused?RealMan wrote:cgarossi by your argument, two people pushing a car along a road would be pointless unless they were both equally strong. If one was weaker then the other, him pushing it would make no difference what so ever.
Rethink what you're saying.0 -
I disagree.
CG has it spot on.0 -
cgarossi by your argument, two people pushing a car along a road would be pointless unless they were both equally strong. If one was weaker then the other, him pushing it would make no difference what so ever.
Rethink what you're saying.
No, they are pushing in the same direction, which is entirely different. That would be Strongman + Weakman = Force
Pedals are:
Downward Force - Upward Force = TotalForce0 -
Its a simple mistake to make.
Two people pushing a car. Two people lifting a weight. Two people standing on scales. Any of these is the same situation. Forces do not "cancel out" when one is smaller.cgarossi wrote:cgarossi by your argument, two people pushing a car along a road would be pointless unless they were both equally strong. If one was weaker then the other, him pushing it would make no difference what so ever.
Rethink what you're saying.
No, they are pushing in the same direction, which is entirely different. That would be Strongman + Weakman = Force
Pedals are:
Downward Force - Upward Force = TotalForce
Both the downward force and the upward force have the same effect on the chain, which in turn turns the wheel.
Turn that minus to a plus and you will be correct 0 -
RealMan wrote:Sitting down, there's not a whole lot of difference between one half pedal turn, upstroke or down stroke. This is probably because on the up stroke, all your muscle is being put into creating the force. You have the saddle and the handlebars to hold yourself against, and as we all know, you can exert more force with one leg then your bodyweight can do under the acceleration due to gravity (try doing a one legged squat - its easy).
This might mean that you can actually accelerate quicker using upstrokes rather then down strokes, when sitting down. I'm not too sure though.0 -
cgarossi wrote:and the force on both pedals increases by the amount you can make your muscles apply.
Wrong!
So wrong it makes me want to reach out and batter you around the head!
Any force you apply on the upward pedal is removed from the downward force, since they are both connected via the axle.
So you're implying that pulling up actually creates less torque than not pulling up...
Effectively you are bracing your downstroke against the rear pedal so you can apply a force greater than your body weight.0 -
ride_whenever wrote:So you're implying that pulling up actually creates less torque than not pulling up...
Effectively you are bracing your downstroke against the rear pedal so you can apply a force greater than your body weight.
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bails87 wrote:What about when you're sitting rather than standing?
This is the bit I added into my last couple of posts - when sitting I believe you can pull up with some force as you would pull yourself into the saddle. I am not sure what magnitude it would or could be. We are most likely to be pedaling at a constant rate and not accelerating. Or even how effective it is. I know that if in the saddle and what a burst of speed, or torque I hover just off the saddle to apply it and push down hard.0 -
That was an overly simplistic way of showing it, I applogise.
You are wrong because you are giving with one (downstroke) and taking away with the other! (upstroke)
You have to remember the cranks and axle make up the same resistive force and you cannot have two opposite actions acting upon it. The net force applied will always be the same!0 -
Its circular motion!! They're both acting in the same direction with regards to the circle!0
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To be able to pull up on the pedal, you must push down somewhere. That is... the other pedal.This is most true for sprinting out of the saddle, when we accelerate maximally.
The forces do not add together.0 -
cgarossi wrote:That was an overly simplistic way of showing it, I applogise.
You are wrong because you are giving with one (downstroke) and taking away with the other! (upstroke)
You have to remember the cranks and axle make up the same resistive force and you cannot have two opposite actions acting upon it. The net force applied will always be the same!
But you haven't. :?
Both forces are driving the cranks in a (from the drive side) clockwise direction.
I may well be missing something, but I still don't see how pulling in a clockwise directin counteracts pushing in a clockwise direction.
Isn't it like two people lifting a heavy suitcase? If one pulls the handle up, while another lifts/pushes from the bottom, the suitcase will move up. just because one force is 'pulling' and the other is 'pushing' doesn't mean they're counteracting each other. Or does it? Feel free to correct me!0 -
They aren't
One is being pushed, the other pulled. Two wholly different actions, and the two cranks are one and the same! If they were seperate it would be a different matter.
Your downwards push is translated into an upwards push on the other side, cancelling out your efforts to pull it up. And vice versa. If you could apply extra power to the upwards pull it would cancel out any efforts made towards pushing on the opposite side crank.
It only becomes effecient when there are both pushing and pulling in equal amounts since you end up using effectively half the muscle power in each leg but getting the same amount of power. But in reality that never happens.0 -
I'm sorry but they do.
Again, another experiment I suggested a few pages ago.
Get a bike with SPDs. Put it in a big gear. Jump on it, put all your weight on one pedal. Stop. Put all your weight on one pedal, whilst pulling up on the other pedal. You will accelerate much, much quicker.cgarossi wrote:They aren't
One is being pushed, the other pulled. Two wholly different actions, and the two cranks are one and the same! If they were seperate it would be a different matter.
Your downwards push is translated into an upwards push on the other side, cancelling out your efforts to pull it up. And vice versa. If you could apply extra power to the upwards pull it would cancel out any efforts made towards pushing on the opposite side crank.
It only becomes effecient when there are both pushing and pulling in equal amounts since you end up using effectively half the muscle power in each leg but getting the same amount of power. But in reality that never happens.
I would love for you to meet my physics professor, he would cry if he heard you talk like that. The forces combine. Again, think about a weaker man and a stronger man pushing a car.
Why do you think tug of war teams exist? Surely, if they're not all pulling at the exact same force, there's no point having all the weaker guys?0
This discussion has been closed.
