SPD's power advantage....Myth?

supersonic

Even standing up the most force you can apply to the pedals is your body weight, push/pull and for every kg you pull up, your also pushing an extra kg down, so that's 2Kg gained of force.

I used to think that, but was only looking at high cadences where the effect is diminished. Imagine a low rev situation. Imagine the cranks barely turning,or even a gear so high it was not turning at all. All your weight on one foot; you can pull up with the other. The force adds chain tension.

snailracer

tjwood wrote:

All you've done is argue about shoes. This is nothing to do with pedals... ;-)

It's not about the bike, either

meanredspider

snailracer wrote:

Good running shoes do not absorb energy

Absolute rubbish! Try this experiment: put your "good running shoes" on and jump off a chair. See how high you bounce. Same height as the chair? 6"? 1"? Or nothing at all? Where's all that energy gone?

Here's what Asics say about their Kayano 16 shoes (a widely recognised "good running shoe"):

ASICS GEL is a silicone-based cushioning system designed to meet the needs of both professional and recreational athletes. Rearfoot GEL provides cushioning in all directions, absorbs impact forces and helps to stabilise the foot during heel contact.

snailracer

meanredspider wrote:

snailracer wrote:

Good running shoes do not absorb energy

Absolute rubbish! Try this experiment: put your "good running shoes" on and jump off a chair. See how high you bounce. Same height as the chair? 6"? 1"? Or nothing at all? Where's all that energy gone?

Here's what Asics say about their Kayano 16 shoes (a widely recognised "good running shoe"):

ASICS GEL is a silicone-based cushioning system designed to meet the needs of both professional and recreational athletes. Rearfoot GEL provides cushioning in all directions, absorbs impact forces and helps to stabilise the foot during heel contact.

OK, now jump off a chair with hard clipless shoes on and see if you bounce any higher. I think you'll find that the shoes make no measurable difference whether they are hard or soft, because almost all the important stuff happens in the legs.
A spring absorbs impact forces, as does a damper. One returns the energy, the other dissipates it. But a shoe is neither a big enough spring or damper to make much difference.

meanredspider

snailracer wrote:

OK jump off a chair with clipless shoes on and see if you bounce any higher.
A spring absorbs impact forces, as does a damper. One returns the energy, the other dissipates it.

I wouldn't bounce any higher because all the shock goes through my joints. Jump off a 6' wall and choose the footwear to land on - running shoes or clipless shoes. The point of the clipless system is to remove as much parasitic energy loss as possible - hard soles strapped tightly to your foot. Part of the purpose of a running shoe is to absorb unwanted impact energy - it acts as a damper/spring system - but it is heavily damped else you would bounce in the chair experiment. The clipless shoe has almost no damper/spring characteristics.

rjsterry

The Beginner wrote:

Even standing up the most force you can apply to the pedals is your body weight, push/pull and for every kg you pull up, your also pushing an extra kg down, so that's 2Kg gained of force.

I can't 'pull' all my ride, but even sitting I can on my steeper bits and gain power, AND by using different muscles to when not pulling, so not tiring my normal peddling muscles, I get a power and an 'efficiency' (on the basis my normal pedaling muscles stay fresher) gain.

Makes me puff and pant like someone on a 20/day habit as well, so 'push/pulling' is increasing my Oxygen consumption!

Simon

Not sure I agree with this. Your leg miscles are more than capable of lifting your body weight and quite a lot more.

rjsterry

snailracer wrote:

meanredspider wrote:

snailracer wrote:

Good running shoes do not absorb energy

Absolute rubbish! Try this experiment: put your "good running shoes" on and jump off a chair. See how high you bounce. Same height as the chair? 6"? 1"? Or nothing at all? Where's all that energy gone?

Here's what Asics say about their Kayano 16 shoes (a widely recognised "good running shoe"):

ASICS GEL is a silicone-based cushioning system designed to meet the needs of both professional and recreational athletes. Rearfoot GEL provides cushioning in all directions, absorbs impact forces and helps to stabilise the foot during heel contact.

OK, now jump off a chair with hard clipless shoes on and see if you bounce any higher. I think you'll find that the shoes make no measurable difference whether they are hard or soft, because almost all the important stuff happens in the legs.
A spring absorbs impact forces, as does a damper. One returns the energy, the other dissipates it. But a shoe is neither a big enough spring or damper to make much difference.

Well, I can walk a lot faster and longer in my stiff-soled walking boots than my squashy (admittedly cheap) trainers, so I think the stiffness of the shoe makes a significant difference.

iPete

snailracer wrote:

My usual post when this topic comes up:
http://www.bikeradar.com/gear/category/ ... s-10-35398

Stops your feet sliding around, no straps= foolproof release.

= Toe pain :!:

Not to forget faffing around to flip them the right way up..

gbsahne001

iPete wrote:

Not to forget faffing around to flip them the right way up..

Sorry, No this doesn't happen if you've used them long enough, as it becomes second nature and I still find them easier to get back in than SPD's.

However I now prefer SPD's, as they're easier to get out / unclip than the toestrap tension I was using

roger_merriman

Really SPD's or other clipless are a way of getting a good pedal.

Road flats don't cut the mustard.

But MTB flats have come a long way. But they would look rather silly on a roadie.

The up pull is a red herring though fun for tricks etc.

always_tyred

I heard the other day that Chris Hoy trains on flats. And Alberto Contador. They are way better. They only use clipless pedals for races because of sponsors. That Dr. bird knows right what she's talking about.

snailracer

meanredspider wrote:

snailracer wrote:

OK jump off a chair with clipless shoes on and see if you bounce any higher.
A spring absorbs impact forces, as does a damper. One returns the energy, the other dissipates it.

I wouldn't bounce any higher because all the shock goes through my joints. Jump off a 6' wall and choose the footwear to land on - running shoes or clipless shoes. The point of the clipless system is to remove as much parasitic energy loss as possible - hard soles strapped tightly to your foot. Part of the purpose of a running shoe is to absorb unwanted impact energy - it acts as a damper/spring system - but it is heavily damped else you would bounce in the chair experiment. The clipless shoe has almost no damper/spring characteristics.

If running shoes were in fact heavily damped, the soles would progressively deform after a few steps until they were hard and thin. This does not happen because they are more spring than damper. And the foot/leg is the bigger spring and damper.

No matter what shoes you wear, when you jump off a 6' wall your legs will bend much, much more than the soles of the shoes will compress. If the sole compresses, say, 10mm, your foot (NOT your shoe) would bounce 10mm, tops. Your foot in a totally "damped" shoe would bounce 0mm. No shoe would bounce you 6' back to the top of the wall, the shoe didn't get that much energy to begin with - it's all in the legs.

Cycling is low-impact. There is no "shock" to speak of. A more appropriate example is walking across a trampoline lined with inflated tyres - your shoes won't make much difference.

snailracer

iPete wrote:

snailracer wrote:

My usual post when this topic comes up:
http://www.bikeradar.com/gear/category/ ... s-10-35398

Stops your feet sliding around, no straps= foolproof release.

= Toe pain :!:

Not to forget faffing around to flip them the right way up..

Toe pain? I have not experienced this, even when wearing sandals. The cups stop my feet from sliding forward, I am not pushing forward into them with much force.

Slight faff flipping them the right way up, but no more so than some clipless systems. And even if I put my foot on the wrong side of the pedal, I can still pedal on it.

meanredspider

snailracer wrote:

If running shoes were in fact heavily damped, the soles would progressively deform after a few ..........

.......is no "shock" to speak of. A more appropriate example is walking across a trampoline lined with inflated tyres - your shoes won't make much difference.

The shoes only return completely to their original state after the pressure is released from them and even that action is damped. At no point did I say they were "totally" damped - they are a spring/damper system - and dampers, as you correctly point out absorb energy and which they release as heat (I'm a mechanical engineer by profession and a fellow of the Institution - oh, and I set up my own race car suspension - I think I understand spring/damper systems!). The fact that they are damped at all means energy is absorbed. They are designed to absorb energy - go back and read the Asics quote. And shock is only a high rate of energy transfer. The trampoline example is ridiculous too - it has nothing to do with a bike! What it does show is what the shoes would be like if they were just springs.

There's absolutely no point in taking this further. You either don't understand or don't want to understand. Just count the number of TdF riders arriving in Paris in trainers....

pastryboy

All else aside, everyone who uses SPD has used flats in the past. The praise for SPD is almost universal with very few people going back to flats. That's enough for me.

snailracer

pastryboy wrote:

All else aside, everyone who uses SPD has used flats in the past. The praise for SPD is almost universal with very few people going back to flats. That's enough for me.

Yes, but how many tried out strapless toe cups in between?

alfablue

snailracer wrote:

pastryboy wrote:

All else aside, everyone who uses SPD has used flats in the past. The praise for SPD is almost universal with very few people going back to flats. That's enough for me.

Yes, but how many tried out strapless toe cups in between?

1 (at least): me.

Tried all formats, only happy with spd's. And I was someone who once proclaimed it was stupid to fix your feet to the pedals :oops:

rolf_f

Always Tyred wrote:

I heard the other day that Chris Hoy trains on flats. And Alberto Contador. They are way better.

'You heard the other day' - interesting if true but, unless backed up with something more solid than random hearsay from somewhere indeterminate, somewhat meaningless.

snailracer

meanredspider wrote:

snailracer wrote:

If running shoes were in fact heavily damped, the soles would progressively deform after a few ..........

.......is no "shock" to speak of. A more appropriate example is walking across a trampoline lined with inflated tyres - your shoes won't make much difference.

The shoes only return completely to their original state after the pressure is released from them and even that action is damped. At no point did I say they were "totally" damped - they are a spring/damper system - and dampers, as you correctly point out absorb energy and which they release as heat (I'm a mechanical engineer by profession and a fellow of the Institution - oh, and I set up my own race car suspension - I think I understand spring/damper systems!). The fact that they are damped at all means energy is absorbed. They are designed to absorb energy - go back and read the Asics quote. And shock is only a high rate of energy transfer. The trampoline example is ridiculous too - it has nothing to do with a bike! What it does show is what the shoes would be like if they were just springs.

There's absolutely no point in taking this further. You either don't understand or don't want to understand. Just count the number of TdF riders arriving in Paris in trainers....

As a mech eng you would realize that, if the shoes return completely to their original state, then the spring factor is dominant over the damping factor.

"absorbs impact forces" <> absorbs energy.

Plus, you quoted advertising blurb, not a technical article. I would not expect precise terminology to be used in an advert.

Walking across a trampoline is much more similar to riding a bike than jumping off a 6' wall.

always_tyred

alfablue wrote:

snailracer wrote:

pastryboy wrote:

All else aside, everyone who uses SPD has used flats in the past. The praise for SPD is almost universal with very few people going back to flats. That's enough for me.

Yes, but how many tried out strapless toe cups in between?

1 (at least): me.

Tried all formats, only happy with spd's. And I was someone who once proclaimed it was stupid to fix your feet to the pedals :oops:

Yup, me too.

Flats might be comparable or better than spd's IF you ride on the flat and IF you aren't a practised cyclist. But this Dr seems to have assumed it applies more generally than this.

There is no account taken of the fact that pulling up when climbing out of the saddle is a way of utilising upper body muscles, or that it might be possible to pull up with one leg and push down with the other, without compromising the downstroke.

Its an extrapolation of assumption on top of an assumption.

Oh, and strapless toeclips are pointless. They are inconvenient flats.

snailracer

Rolf F wrote:

Always Tyred wrote:

I heard the other day that Chris Hoy trains on flats. And Alberto Contador. They are way better.

'You heard the other day' - interesting if true but, unless backed up with something more solid than random hearsay from somewhere indeterminate, somewhat meaningless.

+1
Very interesting, I can see how it would make sense with respect to developing an efficient action, would definitely like to see a reference/source.

snailracer

Always Tyred wrote:

...
Oh, and strapless toeclips are pointless. They are inconvenient flats.

-1.
They work for me. Although the ones I use are designed to be used strapless, they are short toe "cups" that do not have a long, spindly cage or even any holes to attach a strap.

always_tyred

snailracer wrote:

Always Tyred wrote:

...
Oh, and strapless toeclips are pointless. They are inconvenient flats.

-1.
They work for me. Although the ones I use are designed to be used strapless, they are short toe "cups" that do not have a long, spindly cage or even any holes to attach a strap.

Okay then, what technical benefits do they provide?

snailracer

Always Tyred wrote:

snailracer wrote:

Always Tyred wrote:

...
Oh, and strapless toeclips are pointless. They are inconvenient flats.

-1.
They work for me. Although the ones I use are designed to be used strapless, they are short toe "cups" that do not have a long, spindly cage or even any holes to attach a strap.

Okay then, what technical benefits do they provide?

They locate my feet accurately and stop them from sliding around on the pedals. They provide foolproof release, are cheap, can be used with any shoe and require no maintenance or setup.

Their small size stops them from snagging on the ground and makes them easy to "flip" as the cage does not obstruct the platform. If you miss the flip, you still have a real pedal to push on.

Obviously they don't help for "furious" cranking or "pulling up", but they do help the "kick forward" at 12 o'clock.

always_tyred

Okay, so other than convenience, they aren't as good as clipless pedals.

Other than having to flip them around, they are as good as drilled flats.

snailracer

Always Tyred wrote:

Okay, so other than convenience, they aren't as good as clipless pedals.

Other than having to flip them around, they are as good as drilled flats.

Drilled flats do not provide accurate location. And they'll bite yer leg at inconvenient moments :P

always_tyred

snailracer wrote:

Always Tyred wrote:

Okay, so other than convenience, they aren't as good as clipless pedals.

Other than having to flip them around, they are as good as drilled flats.

Drilled flats do not provided accurate location. And they'll bite yer leg at inconvenient moments :P

I can honestly say that even as a child I never had very much trouble finding the pedal or putting my foot on the part of it I wanted.

I'm being a bit of a devil's advocate, to be honest. I used strapless toe clips for years but once you make the move to stiff soled shoes and clipless, there's no point in going back, there really isn't.

snailracer

Always Tyred wrote:

snailracer wrote:

Always Tyred wrote:

Okay, so other than convenience, they aren't as good as clipless pedals.

Other than having to flip them around, they are as good as drilled flats.

Drilled flats do not provided accurate location. And they'll bite yer leg at inconvenient moments :P

I can honestly say that even as a child I never had very much trouble finding the pedal or putting my foot on the part of it I wanted.

I'm being a bit of a devil's advocate, to be honest. I used strapless toe clips for years but once you make the move to stiff soled shoes and clipless, there's no point in going back, there really isn't.

Drilled flats don't work well with stiff-soled shoes, as they can't bite into the hard tread. Toe cups work fine with hard treads, though.

I would say you truly can't go back after riding clipless, because you lose proficiency with flat pedals.

itsbruce

snailracer wrote:

meanredspider wrote:

snailracer wrote:

Good running shoes do not absorb energy

Absolute rubbish! Try this experiment: put your "good running shoes" on and jump off a chair. See how high you bounce. Same height as the chair? 6"? 1"? Or nothing at all? Where's all that energy gone?

[/i]

OK, now jump off a chair with hard clipless shoes on and see if you bounce any higher.

Should I be holding the watermelon while I'm doing this?

itsbruce

snailracer wrote:

My usual post when this topic comes up:
http://www.bikeradar.com/gear/category/ ... s-10-35398

Stops your feet sliding around, no straps= foolproof release.

I never see any bikes with them because nobody knows they exist. Probably because they are cheap and don't make much money for the bikeshops.

They are also ugly, which is either good or bad, depending on your priorities.

Not only are they ugly, but they're not going to work well for people with small or large feet; the requirement to have the toes hooked under the clip would push their feet into an unnatural position.. I'd rather just go with flat pedals than have those forcing my feet into one particular place; I've always had a good pedalling technique on flats (although I prefer clipless).

snailracer wrote:

I would say you truly can't go back after riding clipless, because you lose proficiency with flat pedals.

Based on any actual evidence? I mostly ride fixed, these days, with A530s on the bike. Don't have any problems riding the bike with regular shoes on; clipless gives more control and better speed, particularly uphill, but I haven't lost any technique wrt flats. Quite the reverse.