How much more effecient are SPD's compared to flats?

SFB wrote

my position is scepticism

your position is to try to disprove anything anyone says, ever
because it gives you a semi

Have you ever whitnessed a train where the regulator is opened to fast?
Have you ever seen an unbalanced washing machine spin up, thats a non smooth power delivery as it takes more power/effort to move it.
There are plenty of walking machine efforts that shake them selves to peices when they try to move.

but these are completely different circumstances, and not even steady state. It's not enough to say "It must be so", you have to say why, and offering a lot of irrelevant examples isn't it. I agree that wheelslip is inefficient, but it's perfectly possible to pedal unevenly without that happening, in fact I think you're deluding yourself if you think you CAN pedal smoothly – look at the diagram for evidence!

Mind you i think sfb would argue that black was white just becuase.

no, I was just remembering something I read about 30 years ago about the staccatto power delivery of a single cylinder engine being better for grip off road. Of course, that may have been apocryphal too…

I freely admit I don't know the answer, but neither am I pretending I do while advancing specious justifications.

your position is to try to disprove anything anyone says, ever

I don't need to disprove things wot ent proved.

also traction engines and washing machines are highly atypical off road vehicles 🙂

QED

perfectly possible to pedal unevenly without that happening, in fact I think you're deluding yourself if you think you CAN pedal smoothly – look at the diagram for evidence!

I know i can pedal smoothly other wise my rear suspension bobs up and down if i mash the pedals round whilst it mat not be perfect it is smooth.
SO for a mtb example just try riding lumpy and watch even your fork bounce. This bounce is energy that is being used in your forks rather that to make you go forwards. You can even feel this on a ridged bike as the tyres will deform.

I know i can pedal smoothly other wise my rear suspension bobs up and down

but isn't that more to do with the movement of the body than the feet ?

Bees should not be able to fly they said. for years and years. Yet they could right in front of our eyes. No argument. Just sight.

Open your eyes and take those blinkers off.

dasnut – go suck sam hill off.

And sbf, who the hell are those two moose pigs you put on this thread?

You need to ride with some hot chicks .

simonfbarnes – Member

I know i can pedal smoothly other wise my rear suspension bobs up and down

but isn't that more to do with the movement of the body than the feet ?
if you want to go that why then riding in ridged spd shoes your feet dont move your legs do.

Open your eyes and take those blinkers off.

look at the diagram, the torque varies widely with the angle – in order to smooth it out you'd have to continuously vary the force with the angle to keep it the same.

And sbf, who the hell are those two moose pigs you put on this thread?

I shall tell them your opinion tomorrow, pretty boy…

if you want to go that why then riding in ridged spd shoes your feet dont move your legs do.

uh, if your feet don't move relative to the bike then neither would the pedals!

How much more efficient? About this much <————————->

SFB – it is so obvious to anyone who uses spds – the muscle that lifts my toe has developed significantly since I stated using spds. If you are using more muscles yo either put out more power – or the same power at a lower loading each muscle.

It makes a significant and easily noticed difference

If you are using more muscles yo either put out more power – or the same power at a lower loading each muscle.

except the limit once immediate glycogen stores are depleted is your metabolic rate, not your muscular power.

if you want to go that why then riding in ridged spd shoes your feet dont move your legs do.

uh, if your feet don't move relative to the bike then neither would the pedals!

Your feet don't move relative to the pedals the pedals rotate about an axis.
Lots of bits of your body are moving relative to the bike but your feet dont do anything other than go around and around. Your ankles move both relative to the bike and your body as do your legs this is the bit that you have to smooth out to get effficent energy transferotherwise you are just wasting it.

but your feet dont do anything other than go around and around

I'm not sure where this is going – do you mean in that case that the pedals and feet are irrelevant ?

simonfbarnes – Member

but your feet dont do anything other than go around and around

I'm not sure where this is going – do you mean in that case that the pedals and feet are irrelevant ?

They are largly in terms of a smooth delivery. The stiffness of the sole of the shoe will have much more of an impact on effecent energy transfer and hence road riders and xc racers having stiff soles. Downhillers have a slightly different set of priorites and are not looking for just peadling effeciency which is why they chose to use differnt type of shoe.

All of this is irrelevant for the average rider.
If the pedal you prefer gets you where you want to go and provides the confidence to let you ride the way you want to, it's already as efficient as it needs to be.

The stiffness of the sole of the shoe will have much more of an impact on effecent energy transfer

what tosh! If there were significant efficiency loss in the shoe it would heat up 🙂

it's already as efficient as it needs to be.

which is why I said 0% at the start 🙂

"Having said that, on spds, it is very very easy to spin well compared to flats, as they pull your feet round nicely and teach you to move your feet in nice circles. But you can develop a very efficient spin on flats with practice."

That's the argument I support.

I do bounce a little bit on flats when downhilling my HT, but only because I get stiff and lazy in the legs.

BTW. Black is not White; White is Black.

Yep, I got your point from the start SFB.
Unless you're an elite athlete, it makes no difference at all.
Extracting maximum performance to win nothing produces a bigger loser.

what tosh! If there were significant efficiency loss in the shoe it would heat up

it will heat up YOU just wouldn't notice it happening.
I'm now feed up of talking to a argumentative sod like you who will just stick to his tiny little point of view and not accept anything with out arguing even TJ will accept things.
Oh and the op doesn't ask about how efficent they are for the general rider but just how efficent they are.

I'll repeat for those of you who missed it.

clipped in?
you ****!

specially for burmaboy 😉

and for everyone, don't get so uptight, its only bike riding!

I have only read the first page, so sorry if that have already been said, but you don't pull up… Or if you do, well learn to pedal correctly. Pedalling is a circular motion. And obviously spd's allow you to provide continuous power through the circle.
As for the "how much efficiency do I gain", well it's going to depend. But if your mtbing doesn't involve cycling around a muddy field with no camel back and a flashy lycra shorts, you'll be surprise that there is much more things you can do to improve your efficiency than just riding spd's (getting a upy downy seat post to start with).

http://youtube.com/watch?v=dNpvASJDpms&feature=related

i certainly climb better being clipped in and on certail decents my feet feel more secure.look on wikipedia there are stats to show more efficiency up to 30%

Try riding SPDS in trainers with no cleats.

This just proves SPDs are useless.

Try getting home, still pedalling your bike, with a damaged leg with flats, **** useless

I did once ride back, alone, about a mile from a very isolated spot where I had broken my leg.

I was thankful in one sense that I had SPDs because that helped me pedal using just one leg. I tried gently using my other one, thinking I was probably exaggerating the injury, but all that happened was the leg went longer and shorter as I pedalled.

In another sense, I was less thankful that I had SPDs, because that was what caused the leg break in the first place.

I hate not being clipped in it is so much more efficient riding up hills with spd pedals as you pull on the up stroke.I never ride without clipless pedals

the leg went longer and shorter as I pedalled.

That makes me feel kinda sick.

It reminded me of a pump, going in and out. I wasn't feeling too chirpy either.

Oddly, because of the body's defence mechanism, I wasn't feeling any pain from the broken leg (spiral fracture of tib right down by the ankle plus snapped fib) at that time (certainly kicked in as soon as I knew I was safe) but my pedalling leg was aching like mad, doing all the work riding a mile or so through the gloop with the saddle down low.

If being attached to your pedals is no more efficient that not being attached to your pedals, why have road and track cyclists been using straps with cleats and then clipless pedals for years?

Thats a photo from circa 1936, from the Giro, all using toe clips, cleats & straps, must work otherwise why not as I'm certain there were no such things as crank based power meters or complicated human bio-mechanical analysis to disprove otherwise.

and look those bikes from 1936 have the same quick releae mechanism as some mountain bikes still have today – thats progress folks!
well if it worked for them…. 😀