First attempt with SPD's today in 30 mins

supersonic

How did you measure it, or is it just perception?

As I said, your preferred method always works out more efficient. But overall, pulling is least efficient.

So is entirely possible for a group who are actively pullers to be more efficient than if they are not pulling, because that is what they are used to and that is what they have developed.

So as with many things cycling: do what works best for you.

Oxygen Thief

RealMan wrote:

supersonic wrote:

But the studies do not show that. They show overall a reduction in efficiency.

I dunno I've been doing a study that's gone over a couple of years. I've been the only participant, but I've found it makes it more efficient. So have all the other decent road cyclists I've met.

How did you measure that they work? Reach higher top speed? Get around a track in a PB?

antfly

Robots can`t ride bikes.
It`s purely anecdotal evidence but I definitely go faster when I pull up but it does take a lot more effort so it may well be inefficient.

Will Snow

RealMan wrote:

I dunno I've been doing a study that's gone over a couple of years. I've been the only participant, but I've found it makes it more efficient. So have all the other decent road cyclists I've met.

Please dont claim to be scientific and say stuff like this, it offends me. Plus if you wrote that in your alevel paper I think youd fail just on principle.

I think Supersonic nailed it a few threads back, at low cadence then you can pull up and it will make a difference, but a high cadence you cant match the speed or the power on the upwards leg. I think this is gist of what you are saying.

Anonymous

Aidy wrote:

yeehaamcgee wrote:

Aidy wrote:

The limiting point at where you apply brakes whilst pushing with one hand is directly equivalent to your weight. If you pushed any harder you'd leave the floor.

By pulling the opposing pedal up, you can overcome this limit.

Incorrect. By having your feet planted on the floor and turning with your hands, you not only have your weight turning the cranks, you also have the strength in your legs, core, arms and so on, pushing against the floor to assist in turning.
This does not factor when you're supporting your weight on the cranks.

Um. Try again.
If you're pushing against the floor to apply force, then you're pushing the pedals up.

In my scenario, you push the leading pedal down with one hand. You can't push harder than your body weight, or you leave the ground.

If you pull up as well, you can overcome this limit.

Erm, what?
What my point regarding your explanation is that, if you are stood on the floor, turning the cranks with your hands, then yes, you CAN apply a pushing force with one hand AND a pulling force with the other.
However, that is because you are firmly planted on the floor. Your feet being on the floor allow you to push down with one arm, and pull up with the other by pushing against the floor.
You can put your entire bodyweight on one side of the cranks (in your example) whilst enhancing that by forcing your leg into the floor on the other side, and pulling with all your might.

This is not the same as when riding on SPDs, because in the riding case, you don't have anything to brace yourself against to apply that extra force.

It doesn't matter what cadence, or what loads, it simply cannot be done.

Aidy

yeehaamcgee wrote:

You can put your entire bodyweight on one side of the cranks (in your example) whilst enhancing that by forcing your leg into the floor on the other side, and pulling with all your might.

Er. You what?

That makes no sense at all.
If you're pushing down on one pedal, and have your other foot on the floor, there's absolutely no way you can apply more than your bodyweight in force. In fact, if you're forcing your bodyweight down, the amount of force you can apply is lower.

Let's try another thought experiment:

Consider a freestanding bicycle of sufficient weight that you can't lift it off the ground.
Let it have enough resistance to motion that you can not pedal it with one hand.
Stand on a skateboard next to it.

Can you propel yourself forwards using just one hand on a pedal?
Can you propel yourself forwards using two hands, one on each crank?

Will Snow

I think this whole thread boils down into points. You either think SPD's make you go faster for whatever reason, you think they dont off significant power gain, or you dont really give a monkeys anymore and you like clips/flats for some other reason, ranging from security to perceived efficiency gains. Talk of riding bikes on the moon, using your arms with your face smooshed into the saddle isnt really going anywhere. Go out and ride!! haha

wesk

But do you ride a bike with just your feet on the pedals?

Personally, when going for it up hill, I tend to stand up, and hold on to the bars.
I then keep my arms as ridgid as steering the bike will allow, using them as brace point via my torso as lever so that I can push and pull to a greater level than pushing alone.

That's also why for me, bar ends are better for climbing as they alloy my arm to rotate and my bicep to come into play more as a brace and why I can't climb as well on risers.

Here's a question, how does a track cyclist accelarate at the start of a race? Is it just by pushing? If so, then I'll concede, but I don't think that with double straps instead of spd's due to ripping feet out of clipless pedals that they don't pull.

Will Snow

lol or not then

wesk

yeah, i typed that while you posted

Will Snow

I'll let you off then (but just this once)

bike-a-swan

Aidy wrote:

supersonic wrote:

I agree at lower cadences and higher gears you can generate more overall torque than simply your body weight on the pedal. I disagree you can do it at higher cadences. Where it crosses over I do not know.

That's a limit of the amount of power a person can put out, rather than any kind of mechanical limit.

This is exactly it. The limit is biomechanical, not a because the physics changes at different speeds.

Yes, I'm back in the labs running simulations, which means I'm back to having chunks of time while they're running to discuss things. Lets go!

Anonymous

Aidy wrote:

Let's try another thought experiment:

Consider a freestanding bicycle of sufficient weight that you can't lift it off the ground.
Let it have enough resistance to motion that you can not pedal it with one hand.
Stand on a skateboard next to it.

Can you propel yourself forwards using just one hand on a pedal?
Can you propel yourself forwards using two hands, one on each crank?

Oh for god's sake. yes, you can apply more force with two arms, because your feet are connected to the freaking floor. :roll:

However, if you could do a handstand in the pedals (I'm assuming that for this to work, there is very little bike in the way, allowing you to actually place both arms on the cranks) then you could not put any more power than your weight through them.

Pushing against the floor allows you to put out more power than your weight.

bike-a-swan

yeehaamcgee wrote:

then you could not put any more power than your weight through them.

This is the only thing on here I have issue with, I'm afraid it's wrong.

Ok, I'm going to try another shot at explaining why. I tested this earlier. Get your bike, sit on it, leaning against a wall. Set the cranks vertical. Put all your weight through the lower pedal. Then try and put more force through it. You can do this by pulling up in the opposing pedal.

Agreed?

Will Snow

nope

RealMan

Will Snow wrote:

RealMan wrote:

I dunno I've been doing a study that's gone over a couple of years. I've been the only participant, but I've found it makes it more efficient. So have all the other decent road cyclists I've met.

Please dont claim to be scientific and say stuff like this, it offends me. Plus if you wrote that in your alevel paper I think youd fail just on principle.

I was being ironic. Anyone can say they've done a study. It doesn't mean anything.

Anonymous

bike-a-swan wrote:

Ok, I'm going to try another shot at explaining why. I tested this earlier. Get your bike, sit on it, leaning against a wall. Set the cranks vertical. Put all your weight through the lower pedal. Then try and put more force through it. You can do this by pulling up in the opposing pedal.

Agreed?

Nope. Not agreed.

Will Snow

RealMan wrote:

I was being ironic. Anyone can say they've done a study. It doesn't mean anything.

And you are supremely qualified to judge whether those studies are accurate or not?

Life tip, dont use irony on the net, its very difficult to get right without actually hearing the person say it. or, failing that, use the <irony> </irony> tabs...

bike-a-swan

did you try?

RealMan

Will Snow wrote:

And you are supremely qualified to judge whether those studies are accurate or not?

When someone states the "results" of a "study" as pure fact, I will call them on it. A study can be tailor made to prove whatever you want it to prove.

yeehaamcgee wrote:

bike-a-swan wrote:

Ok, I'm going to try another shot at explaining why. I tested this earlier. Get your bike, sit on it, leaning against a wall. Set the cranks vertical. Put all your weight through the lower pedal. Then try and put more force through it. You can do this by pulling up in the opposing pedal.

Agreed?

Nope. Not agreed.

You can. Its just leverage. You pull up on the opposing pedal, this increases the force you can put down on the other pedal.

If the down force stayed the same on the other pedal, while you increased the up force on the opposing pedal, you would suddenly have a situation of unbalanced forces, where the up force is greater then the down force. And then you would accelerate upwards.

Unless you can fly, you're wrong.

supersonic

RealMan wrote:

Will Snow wrote:

RealMan wrote:

I dunno I've been doing a study that's gone over a couple of years. I've been the only participant, but I've found it makes it more efficient. So have all the other decent road cyclists I've met.

Please dont claim to be scientific and say stuff like this, it offends me. Plus if you wrote that in your alevel paper I think youd fail just on principle.

I was being ironic. Anyone can say they've done a study. It doesn't mean anything.

Have you read the references in some of these studies? They seem very well researched, with data to back up what they are saying.

Anonymous

bike-a-swan wrote:

did you try?

Yes, when I had SPDs for some time years ago.
This time? no. I already know the outcome, and quite apart from that, I also understand the physics and mechanics behind the phenomenon.

RealMan

I've only seen the link to one, which seemed to agree with what I was saying. A load of other studies have been quoted, yet never linked to.

bike-a-swan

yeehaamcgee wrote:

bike-a-swan wrote:

did you try?

Yes, when I had SPDs for some time years ago.
This time? no. I already know the outcome, and quite apart from that, I also understand the physics and mechanics behind the phenomenon.

The implication, naturally, being that I don't.

Ok, take this point. Same situation, cranks vertical, all of your weight through the lower pedal. Can you pull up on the raised pedal?

supersonic

RealMan wrote:

I've only seen the link to one, which seemed to agree with what I was saying. A load of other studies have been quoted, yet never linked to.

Did you read the link I provided? Or how about this book, starting form page 119:

http://books.google.co.uk/books?id=msdT ... st&f=false

RealMan

Far too late for me to be trying to read that, I'll give it a look through later. Cheers.

Will Snow

RealMan wrote:

Will Snow wrote:

And you are supremely qualified to judge whether those studies are accurate or not?

When someone states the "results" of a "study" as pure fact, I will call them on it. A study can be tailor made to prove whatever you want it to prove.

...are you aware of how science works? Someone has conducted a study, giving clear results. This makes a theory. Now until someone disproves this theory, it is generally accepted to be fact, unless you can call out discrepancies in their scientific method. Can you call out any problems in their method? Please link to a study holding to your theory.

At the end of the day, Im not gonna trust "sum guy" off the tubes when I have an accredited scientific document (two now, cheers SS) from University taught graduates.

Id also like to point out a very large part of being a scientist is both accepting that you dont know somethings, and accepting that occasionally you are wrong. If you dont do that, well then all you have is blind faith, which is just religion.

supersonic

It is a good read. Some of the conclusions surprised me.

The other article was written by:

THOMAS KORFF1, LEE M. ROMER1, IAN MAYHEW1, and JAMES C. MARTIN2
1
Brunel University, Centre for Sports Medicine and Human Performance, Brunel University, Uxbridge, UNITED KINGDOM;
and 2The University of Utah, College of Health, Salt Lake City, UT

I would say there were worse people to do it than them lol. If it was the Shimano SPD corp, or Flatties R Us, I would be more worried.

RealMan

Will Snow wrote:

Id also like to point out a very large part of being a scientist is both accepting that you dont know somethings, and accepting that occasionally you are wrong. If you dont do that, well then all you have is blind faith, which is just religion.

supersonics link there has been the first study I've seen linked to. Maybe someone else linked to one before, and I missed it. We are on page 20.

Mostly its just been people saying "nope some guy did a study and proved the laws of physics wrong" and have just been expecting everyone to take that as fact, as if the word "study" is some kind of magic word which means the truth.

supersonic wrote:

I would say there were worse people to do it than them lol. If it was the Shimano SPD corp, or Flatties R Us, I would be more worried.

Yes lol.

Will Snow

RealMan wrote:

Will Snow wrote:

Mostly its just been people saying "nope some guy did a study and proved the laws of physics wrong" and have just been expecting everyone to take that as fact, as if the word "study" is some kind of magic word which means the truth.

agreed.