i have absolutely no idea. but there's a formula for you:

science says so

What utter mumbo-jumbo

Until the Vatican approve them I don't see how "science" knows better, do you?! 😡

i suspect although it's difficult to tell from the pics that the rings are not centred on the axis of the axle.

The cranks on handles to wind-up wells are shaped like that – I guess they lose less to bending.

actually forget that, it clearly is centred

As far as I can tell, what those test results are showing you is that the crank flexes. Because of the shape of the curve, it will turn the chainrings slightly due to flex when pushed straight down.

Strange how the graph only shows results for 0 to 60 degrees. I wonder what happens around the rest of the rotation – for instance at 180 degrees?

at 180 degrees theres no force is there?

i guess that depends very much on how smooth a pedaller you are. there will be a point where there is no force but it is only momentary. at this point the other crank will be (hopefully) applying more force due to the flex characteristics.

i might order some now 😆

at 180 degrees theres no force is there?

There is if there's a force at zero degrees 😉

29ers……singlespeeds we don't live in the dark ages…..flatties great is you want to fall over in the mud,lose 50% effiecientcy,and look like a american skater boy….coil shocks.heavy and crap…tubes….why not tubeless?….baggies…just plain silly.

rant over calm……..

flatties great is you want to fall over in the mud,lose 50% effiecientcy

😯

good rant

Why would flatties make you fall over in the mud?

bikerbruce reads MBR…

flat pedals lose about 15%-20% efficiency depending on the rider/shoe/pedal combination.

Given that the average ride isn't done at 100%, the disparity between fittesdt and least fit on a ride is probably massively more, tire choice probably makes a bigger difference, and im not racing its hardly a big deal?

And anyone who thinks they pedal perfect circles is sadly deluded, if you're sat in the saddle your still putting weight on your back foot. So the not "pulling up" only actualy loses you about 5%, the rest is through squidgey soles and crank/pedal flex.

The not pulling up loses you nothing at all, since at best you only unweight the back foot slightly. What loses you more is having to recruit extra muscles to keep your foot in place.

flat pedals lose about 15%-20% efficiency depending on the rider/shoe/pedal combination.

evidence, or just hand waving?

look you get the gist of what i'm saying……if you have carbon soled shoes with uberstiff soles then all is good.
thisisnotaspoon …dont get me started on tyres ;).
flatties rely on a flat sole to grip the pedal…so confuisus shoes with no grip maketh a man fall over in mud.
Bruce

I love internet 'truth'

flatties rely on a flat sole to grip the pedal…so confuisus shoes with no grip maketh a man fall over in mud.

they also have pins – cant say i've ever had a real problem.

flatties are superb in the mud – much better than SPD's when its really claggy 🙂

The not pulling up loses you nothing at all, since at best you only unweight the back foot slightly

Curious, not sure how I manage to pull my shoe out of the cleat on steep bits by slightly unweighting my foot!

It's hilarious that people genuinely believe that pulling up "saves" energy and the belief that pulling up doesn;t in itself use energy. Having flatties and NOT pulling up saves more energy ffs..

Curious, not sure how I manage to pull my shoe out of the cleat on steep bits by slightly unweighting my foot!

Because you're not pedalling efficiently.

Enfit – the pulling up uses different muscles. Not that it does not use energy but you are using more of the total muscle mass to provide thrust. Hence greater efficiency.

Only a minor effect tho for sure

Not pulling up does not save energy, because your trailing leg weighs quite a lot, and if you fail to lift it your front leg has to do that.

Because you're not pedalling efficiently.

What has efficiency got to do with it? How is it possible to pull your foot out of the pedal cleats if you are not pulling up on the pedals?

What has efficiency got to do with it?

Everything, since we're discussing how much less efficient flats are 🙄

Just resurecting it for an argument on a friday.

My masters dissertation was on putting sensors in sports gear so I read arround this stuff.

In summary-
Pedaling 'perfect circles' is more about keeping the tension in the chain as constant as possible, than actualy pulling up as hard as you push down.

Just try it, attach a 25kg weight to your foot (a 25kg sack of spuds maybe?) and try and lift that leg up as if your were pedaling.

A sprinter can put down arround 8x that force (arround 200kg per leg)!

If you could pedal a perfect circle you would detatch your lower leg from your upper leg with the strain on the ligaments.

SPD's are more efficient, but only 20% ish, 10-15% of that is down to shoe design, if you put 5.10 rubber on a set of SPD shoes you get back most of that loss. the remaining 5% is in lifting the dead weight of your foot, shoe and leg. But in most situations SPD riders are doing just the same and not pulling up.

Anyone on a tandem? If you try and ride with the pedals in phase and the second person is significanlty weaker than the other, they feel like the pedals are falling away from them, this is what your back leg experiences when you try and pedal perfect cicrcles, at best it barely adds anything to the torque, normaly it just lifts a fraction if its own weight.

n.b. those figures were based on running shoes which are soft and squidgy.

A stiff BMX shoe will be much closer to the hypothetical 5.10/cycling shoe combo.

since you resurected it and i'm in a taiwan hotel at the mo, the daftest thing i've seen this week are those stepper bikes. again. every f-in trade show you get people 'cruising' the aisles (ie as popular as riding your bike on a busy pavement at rush hour!) on bikes that use up-down motion steppers with a sprung ratchet chain to crank the wheel 🙂 kind of fun in a way but someone's really trying to sell them, still.

someone must have deep pockes to promote them cos show space isn't cheap and i've seen them at shows since year dot, but i've never seen one being used outside a show hall.

optimism can be both wonderful and a bit sad ) anyone ever seen one that may have been bought for real £??

v interesting spoon.

I think 5.10s w/the thinner flats are getting pretty good now. I'm interested in how getting your foot closer to axis of axle improves things, some SPDs are worse now I think.

What you say about pulling up you leg/foot is interesting.
I guess you can create a lot more force from your quads than your hamstrings, so maybe it's better to just use those.

spoon, how about on a fixed wheel, or even accelerating while spinning a fast cadence? that seems to work better when spinning cirles as much as you can. but interesting point about the downforce vs lifting the spuds, got me thinking..

if we could spin near-perfect circles we wouldn't need anti-squat in FS designs right?

Those Powercranks are brilliant for use as a training aid if one leg weaker through injury or disability or you are a professional sack racer and even if you just want to look like cock and have kids throw sticks at you !

For all the efficiency you may gain going up with SPD's if you then feel less comfortable going down (which is often cited by people as a reason for not using SPDs) and therefore go slower on the downhill section, over the whole ride it's not going to gain you any time/speed…personal choice imho.

Off topic though! 😉

Have we done Scott oilers yet?

Fixed gear doesn't make a difference, anyone should be able to pedal so theres always at least some tension in the chain.

IIRC the faster the cadence the less you pull up.

eg.
Stood up sprinting you pull up quite a bit. Which is where SPD's win.

Sat down your somehwere in between, your just about unweighting your leg, SPD's are of some but marginal benifit here.

Spinning at 120rpm+ most subjects were still pushing down well into the upstroke (i.e. past BDC), the downward force on the pedal was greater than what youd expect from just accelerating the weight of the leg.

I'm racking my brain/google trying to find the paper.